External quality assessment for influenza antiviral susceptibility for the European Reference Laboratory Network for human influenza : 2015.
Date: 2017-01-19
Institutions: European Centre for Disease Prevention and Control
Subjects: disease prevention, health care system, health control, infectious disease, public health, research body, research report, scientific cooperation

TECHNICAL REPORT

External quality assessment 
scheme for influenza antiviral 
susceptibility for the European 
Reference Laboratory Network for 
Human Influenza
2015

www.ecdc.europa.eu

ECDC TECHNICAL REPORT 

External quality assessment scheme for 
influenza antiviral susceptibility for the 
European Reference Laboratory Network 
for Human Influenza 

2015 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
This report was commissioned by the European Centre for Disease Prevention and Control (ECDC), coordinated by 
Cornelia Adlhoch (ECDC) and produced by Ian Harrison, with assistance from Angie Lackenby and Catherine 
Thompson, Public Health England, London, UK, and Adam Meijer, RIVM, the Netherlands, on behalf of the 
European Reference Laboratory Network for Human Influenza (ERLI-Net). 

Catherine Thompson and Joanna Ellis, Public Health England, London, UK, and the contractor’s management team 
contributed to the design and planning of the exercise. The panel was produced by the Respiratory Virus Unit, 
Public Health England, London, UK. 

Data services were provided by Quality Control for Molecular Diagnostics (QCMD), Glasgow, UK. Analysis of the 
data was conducted by QCMD and Ian Harrison. 

Suggested citation: European Centre for Disease Prevention and Control. External quality assessment scheme for 
influenza antiviral susceptibility for the European Reference Laboratory Network for Human Influenza – 2015. 
Stockholm: ECDC; 2016. 

Stockholm, October 2016 

ISBN 978-92-9193-987-9 

doi 10.2900/032579 

Catalogue number TQ-04-16-846-EN-N 

© European Centre for Disease Prevention and Control, 2016 

Reproduction is authorised, provided the source is acknowledged 

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External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Contents 

Abbreviations ............................................................................................................................................... iv 
Executive summary ........................................................................................................................................ 1 

Introduction .................................................................................................................................................. 2 
Objectives ................................................................................................................................................ 2 
Study design ............................................................................................................................................ 3 
Organisation ........................................................................................................................................ 3 
Participation ......................................................................................................................................... 3 
Panel description .................................................................................................................................. 3 
Testing ................................................................................................................................................ 3 
Data reporting ...................................................................................................................................... 3 
Data analysis ........................................................................................................................................ 3 
Initial report ......................................................................................................................................... 4 

Results .......................................................................................................................................................... 5 
Panel composition and expected results ...................................................................................................... 5 
EISN-AV15 participation ............................................................................................................................ 5 
Results of phenotypic testing ..................................................................................................................... 7 
Genotypic testing for NA gene substitutions ................................................................................................ 9 
Training ................................................................................................................................................. 11 

Discussion and conclusion ............................................................................................................................. 12 

Recommendations ....................................................................................................................................... 14 
Phenotypic characterisation ..................................................................................................................... 14 
Genotypic characterisation ....................................................................................................................... 14 

References .................................................................................................................................................. 15 

Annex 1. Definition of phenotypic classification ............................................................................................... 16 
Annex 2A. Oseltamivir phenotypic IC50 results presented by laboratories ........................................................... 16 
Annex 2B. Zanamivir phenotypic IC50 results presented by laboratories ............................................................. 18 
Annex 3A. Genotypic results presented by individual laboratories – influenza A(H1N1)pdm09 samples ................. 20 
Annex 3B. Genotypic results presented by individual laboratories – influenza A(H3N2)pdm09 samples ................. 23 
Annex 3C. Genotypic results presented by individual laboratories – influenza B samples ..................................... 26 
Annex 4. List of participating laboratories ....................................................................................................... 29 
Annex 5. List of training activities .................................................................................................................. 30 

Figures 

Figure 1. Panel composition ............................................................................................................................ 5 
Figure 2. Participating laboratories: antiviral susceptibility testing, EISN-AV15 EQA panel ..................................... 5 
Figure 3. Methods used for antiviral susceptibility testing ................................................................................... 7 
Figure 4A. Analysis of phenotypic antiviral susceptibility per sample in the AV15-EQA panel .................................. 7 
Figure 4B. Individual laboratories results for phenotypic antiviral susceptibility testing .......................................... 8 
Figure 5. Assay platforms used for phenotypic testing ....................................................................................... 9 

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TECHNICAL REPORT 

Abbreviations 

AANI 

AARI 

AAHRI 

AV 

AV15 

CNRL 

EISN 

EQA 

No amino acid substitution previously associated with highly reduced inhibition  

Amino acid substitution previously associated with reduced inhibition 

Amino acid substitution previously associated with highly reduced inhibition 

Antiviral 

Influenza antiviral susceptibility external quality assessment panel of ERLI-Net 

Community Network of Reference Laboratories for Human Influenza in Europe 

European Influenza Surveillance Network 

External quality assessment 

ERLI-Net  

European Reference Laboratory Network for Human Influenza 

EU  

GISRS 

HA 

HRI  

IC50 

European Union 

Global Influenza Surveillance and Response System 

Haemagglutinin 

Highly reduced inhibition 

50% inhibitory concentration 

MUNANA 

2'-(4-methylumbelliferyl)-α-D-N-acetylneuraminic acid sodium salt hydrate 

NA 

NAI 

NI  

PCR 

PHE 

QC  

Neuraminidase 

Neuraminidase inhibitors 

Normal inhibition 

Polymerase chain reaction 

Public Health England 

Quality control 

QCMD  

Quality Control for Molecular Diagnostics, Glasgow, UK 

RI  

RIVM 

SNP 

WHO 

Reduced inhibition 

National Institute for Public Health and the Environment, the Netherlands 

Single nucleotide polymorphism 

World Health Organization 

WHO-CC 

World Health Organization Collaborating Centre for Reference and Research on Influenza 

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External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Executive summary 

In June and July 2015, an influenza virus antiviral susceptibility external quality assessment (EQA) was held for 
European reference laboratories. This was the third antiviral EQA panel distributed by the European Reference 
Laboratory Network for Human Influenza (ERLI-Net; previously called CNRL) since the European Influenza 
Surveillance Network (EISN) was established in 2008.  

The objectives of the exercise were to provide participants with an independent mechanism to check performance, 
to provide information for the entire network on capacity (i.e. the number of laboratories having the capability to 
conduct phenotypic and/or genotypic antiviral tests) and on capability (i.e. the ability of individual laboratories to 
conduct such tests), and to accurately report test results to TESSy, The European Surveillance System. 

Overall results for the exercise were broadly encouraging. Twenty-four laboratories from 19 European countries 
participated in the exercise while 14 laboratories opted out as they did not perform assays capable of determining 
antiviral susceptibility. This represents increased capacity (24 laboratories) across the network, compared to the 
first EQA exercise in 2010 (20 laboratories). 

Phenotypic antiviral susceptibility results were encouraging. Eighteen of the 24 laboratories (75%) returned 
phenotypic results, with only nine incorrect results out of a total of 261 (3.4%). One laboratory, using a NA-STAR-
based assay failed to detect the mixed A(H1N1)pdm09 NA-H275Y sample, a problem that has been noted before. 
Three laboratories incorrectly reported ‘normal inhibition’ for zanamivir on the influenza type B NA-I221L [1] 
sample, all using kit-based assays (1 NA-STAR, 2 NA-FLUOR). With regard to the wild type specimens, five reports 
from three laboratories incorrectly interpreted viruses as ‘reduced’ or ‘highly reduced’ inhibition: one such error was 
due to a fold change just over the reduced inhibition threshold, three errors were caused by using the NA-FLUOR 
kit, and one error was merely an incorrect interpretation of an otherwise correct IC50 value. 

All 24 laboratories participating in the EQA used some form of genetic characterisation. Depending on the 
laboratory and the sample involved, techniques varied from pyrosequencing, single nucleotide polymorphism PCRs 
to Sanger sequencing of the neuraminidase (NA) gene. Depending on the method employed, interpretations of 
antiviral susceptibility varied notably.  

Strict marking criteria were applied to the interpretation of genotypic results in order to avoid a number of 
problems that had previously been identified in relation to the routine reporting of antiviral susceptibility data to 
TESSy. Overall, laboratories were able to identify nucleotide polymorphisms. A few issues were noted, e.g. results 
from samples for which only partial genetic information was available were over-interpreted, especially when 
polymorphisms associated with reduced susceptibility were missing (e.g. partial sequencing or SNP PCR). In some 
of these cases, laboratories incorrectly reported ‘normal inhibited’ instead of ‘no interpretation possible’. Several 
laboratories used the wrong assays for the samples, e.g. by using SNP PCR on viruses with the N2 NA; SNP PCR is 
designed primarily for viruses with the N1 NA. These issues were addressed during the training webinars. 

The 2015 EQA showed a general improvement in the technical ability of network laboratories, but also identified 
topics for future training and monitoring. Continued issues with incorrect interpretations of partial genetic 
information were addressed in two webinar training sessions. Some improvement has been seen in this area, 
although further training and support is required. 

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TECHNICAL REPORT 

Introduction 

Influenza viruses cause a highly contagious acute respiratory disease that can spread rapidly and cause high levels 
of morbidity and mortality. With the advent and increased clinical use of antiviral drugs against influenza the 
prevention and treatment of influenza has improved. The neuraminidase inhibitors (NAI) oseltamivir and zanamivir 
were developed through structure-based drug design to mimic the neuraminidase's natural substrate, sialic acid. 
The close similarity to the natural substrate was predicted to limit the emergence of resistance. WHO has 
standardised the terminology used to describe the susceptibility of influenza viruses in terms of the inhibitory effect 
of NAI on the NA enzyme activity as measured by the IC50 of a NAI: normal inhibition (NI), reduced inhibition (RI) 
and highly reduced inhibition (HRI). WHO also uses these three categorised for all amino acid substitutions [2,3]. 
ERLI-Net later adopted these categories.  

Emergence of antiviral resistance is closely monitored through virological surveillance. Very few cases of resistance 
to NAIs were found during clinical trials and post-licensure surveillance. Amino acid substitutions in the NA gene 
associated with highly reduced inhibition or reduced inhibition to NAI were seen in a few cases of clinical 
resistance. In 2007, naturally occurring oseltamivir HRI due to a histidine-to-tyrosine amino acid substitutions at 
position 275 in the N1 NA (H275Y) was observed in former seasonal A(H1N1) viruses, and the oseltamivir HRI virus 
rapidly spread across Europe and worldwide [4,5]. NAI resistance in other influenza A subtypes and influenza B has 
not been widely observed. During the 2009 H1N1 pandemic, oseltamivir was commonly used for treatment and 
post-exposure prophylaxis. A relatively small number of A(H1N1)pdm09 viruses with HRI to oseltamivir, due to the 
H275Y substitution, have been observed since the emergence of this virus. On a few occurrences such viruses 
were detected in larger outbreaks that did not lead to global spread [6,7]. The situation is closely monitored by 
ERLI-Net and the WHO Global Influenza Surveillance and Response System (GISRS) [7,8,9,10]. 

The H275Y substitution in the A(H1N1) subtype is the most common mutation, and the only single polymorphism 
unequivocally considered to confer clinical resistance to oseltamivir in the absence of compensatory or secondary 
amino acid substitutions. Other (H)RI pathways have been described for A(H1N1) viruses so the absence of H275Y 
does not preclude (H)RI via alternative amino acid substitutions. While the H275Y substitution is relatively easily 
targeted by laboratory assays, the situation for the A(H3N2) subtype and influenza B virus is different because 
several substitutions were identified which generate RI [11]. For these viruses, a broader testing strategy is 
required. The gold standard phenotyping test requires isolated and propagated viruses and is therefore not as 
widely performed [12]. Phenotyping tests (IC50 assay) can detect changes in NAI susceptibility (RI/HRI) due to 
previously known – but also unknown – amino acid substitutions in influenza A and B viruses. 

This report presents the results of the influenza virus antiviral susceptibility EQA. EQA panels were distributed in 
June 2015 by Public Health England. Quality Control for Molecular Diagnostics (QCMD) collated the results and 
performed the initial analyses.  

This is the third EQA for influenza antiviral susceptibility conducted for EISN ERLI-Net and laboratories associated 
with the the former EISN Community Network of Reference Laboratories for Human Influenza in Europe. The first 
EQA was conducted in 2010 [13], the second one in 2013 [15,16]. As with all other aspects of influenza 
surveillance, it is essential that the accuracy of influenza antiviral susceptibility testing methods is assessed through 
effective quality control. EQAs are an integral part of quality control and provide a means of externally evaluating 
both individual laboratory performance and performance of the network as a whole. 

Objectives 

The specific objectives of the 2015 EISN influenza antiviral susceptibility testing EQA panel were to measure 
individual laboratory performance in four areas. 

 

 

 

 

To test the participants’ ability to detect nucleotide mutations in the NA gene; these mutations result in 
amino acid substitutions known to confer RI/HRI by NAI in a panel of influenza A and B viruses by 
genotypic and/or phenotypic antiviral susceptibility methods. 
To provide participating laboratories with an independent mechanism to assess the performance of their 
influenza antiviral susceptibility testing methodology. 
To gain insights into the performance of different techniques used for influenza antiviral susceptibility 
testing in European laboratories, thus helping ERLI-Net and ECDC to determine training priorities and 
produce guidelines on the reporting of results and on how to harmonise the interpretation of antiviral data. 
To evaluate test results and assess the quality of data uploaded to TESSy. 

EQA testing also promotes the following overall  objectives: 

Assessment of the general performance standards  
Assessment of the effects of analytical procedures (method, principles and techniques) 
Evaluation of individual laboratory performance 

 
 
 

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TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

 
 

 

Identification and justification of problem areas 
Providing continuing education (testing against samples of known status) and enabling comparisons with 
other laboratories 
Identification of training needs  

Study design 

Organisation 

The EQA panel was designed by staff from Public Health England, together with members of the contractor’s 
management team and several ERLI-Net network members. The panel was prepared and tested by the Respiratory 
Virus Unit at Public Health England, London. Further pre-testing was performed by the WHO-CC at the Francis 
Crick Institute at Mill Hill, London, and the France South National Influenza Centre, Lyon, France. Data provided by 
the participating laboratories were collected online and managed by Quality Control for Molecular Diagnostics 
(QCMD). The panel contents were distributed frozen on dry ice and by specialist courier.  

Participation 

All influenza laboratory contact points in the ERLI-Net were notified in advance of the EQA exercise. Laboratories 
were given the option to opt out of the EQA if they were not equipped for antiviral susceptibility testing. Annex 4A 
lists all EQA participants. 

Panel description 

The panel consisted of two simulated samples containing viruses with amino acid substitutions conferring NAI 
(H)RI alongside eight samples used for the Influenza_2015 (IFN15) panel of which the included viruses did not 
contain amino acid substitutions conferring NAI H(RI). Two simulated clinical samples were provided, containing 
inactivated influenza A(H1N1)pdm09 and influenza B viruses. These inactivated samples contained a viral load that 
allowed direct measurement of IC50 without a virus isolation and propagation step.  

Virus type and subtype were provided for each sample to guide the selection of appropriate tests and analysis. 
Viruses were inactivated with Triton X-100 retaining functional NA enzyme activity [14], aliquoted and stored frozen 
at ˗80° C until dispatched. Laboratories were required to also characterise the eight samples and viruses that had 
been isolated and tested as part of the INF15 panel. One panel was thawed and pre-tested at Public Health 
England using in-house methods. Panels were sent frozen on dry ice to two independent laboratories for pre-
testing. The final panel contents were shipped frozen on dry ice by specialist courier (DG Global Forwarding) on 
15 June 2015, and all were received within two days. The deadline for reporting results was within 28 days of 
receipt of the panel.  

Testing 

Laboratories were expected to only use those genotypic and/or phenotypic methods for antiviral susceptibility 
testing which were readily available in their facility. Laboratories were not penalised for reporting ‘not tested’ if they 
had no suitable testing methods available for one of more samples in the panel. Laboratories were assessed on 
their final interpretation of the obtained results (‘normal’, ‘reduced’, ‘highly reduced inhibition’ or ‘no interpretation 
possible’, based on genotypic and/or phenotypic data).  

Data reporting 

For genotypic characterisation, participants were asked to report the predicted amino acid substitutions based on 
nucleotide sequence detected in the sample and their interpretation of the impact on NAI susceptibility (amino acid 
substitutions associated with (highly) reduced inhibition (AARI, AAHRI), or no amino acid substitution previously 
associated with highly reduced inhibition (AANI)). For phenotypic characterisation, participants were asked to 
report the IC50 value measured and submit their interpretation of the data (‘reduced’, ‘highly reduced’ or ‘normal’ 
inhibition (RI, HRI, NI)). Participants were asked to report if an interpretation was not possible with the used 
methodology, or if a negative result was obtained. Data on the genotypic and phenotypic methods used in the 
participating laboratories were collected online and managed by QCMD.  

Data analysis 

WHO phenotypic classification definitions are shown in Annex 1 [2]. The phenotypic scoring system awards a 
maximum of one point for each analysed sample, irrespective of whether the participating laboratory tested for 
both oseltamivir and zanamivir, or oseltamivir alone. One point was deducted for each incorrect result. No 
distinction was made between samples that were classified as HRI and samples that were classified as RI. The 
maximum achievable score for phenotypic characterisation was 9 points. The genotypic scoring system awarded 

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TECHNICAL REPORT 

one point for a ‘correctly interpreted’ result if the results were obtained through an appropriate test and an equally 
appropriate interpretation. If present, amino acid substitutions associated with reduced inhibition had to be 
correctly identified and reported. The maximum score for genotypic characterisation was 27 points.  

Initial report 

QCMD and Ian Harrison worked jointly to perform an initial analysis of the submitted data. The report of the initial 
analysis along with the expected results were published by QCMD. Copies of these documents can be found on the 
ECDC extranet. 

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External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Results 

Panel composition and expected results 

The influenza type, subtype, strain characterisation and antiviral susceptibility profile with associated amino acid 
substitutions in the NA protein for each sample in the EQA panel are shown in the table below. (Figure 1). Amino 
acid numbering corresponding to the relevant NA subtype is used throughout. The influenza subtype was identified 
in the description of each inactivated panel sample so that participants could target subtype-specific tests 
appropriately. The virus type and subtype for samples tested as part of the Rapid Detection, Isolation and 
Characterisation panel were determined by the receiving laboratories as part of the routine laboratory testing 
workflow. 

Figure 1. Panel composition 

Sample code 

Subtype 

Designation 

Amino acid 
substitutions 
associated with 
(H)RI 

Oseltamivir 
 interpretation 

Zanamivir  
interpretation 

EISN_INF15-01  B-Yam 

B/England/531/2014 

none 

EISN_INF15-02  A(H3N2) 

A/Switzerland/9715293/2013  none 

EISN_INF15-03  n/a 

n/a 

EISN_INF15-04  A(H3N2) 

A/England/599/2014 

EISN_INF15-05  A(H3N2) 

A/England/215/2011 

EISN_INF15-06  A(H1N1)pdm09  A/ENG/579/2014 

EISN_INF15-07  A(H1N1)pdm09  A/England/226/2010 

EISN_INF15-08  B-Vic 

B/England/197/2014 

n/a 

none 

none 

none 

none 

none 

No inhibition 

No inhibition 

n/a 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

n/a 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

No inhibition 

AV15-01 

AV15-02 

A(H1N1)pdm09  H275Y mix 

275H/Y 

(Highly) reduced inhibition 

No inhibition 

B-Vic 

B/Lyon/CHU/15.216/2011 

I221L 

Highly reduced inhibition 

Reduced inhibition 

AV15-01 and AV15-02 participants were provided with information on type/subtype of samples. AV15-01 reduced susceptibility to 
oseltamivir as a result of viruses with mixed NI and HRI NAI phenotypes.  

An ‘expected results letter’ with strain designations was sent to all laboratories after testing was completed. The 
strain designations together with the complete gene sequences (downloadable from GISAID) allowed the 
laboratories to check the specificity of primers and probes used for testing. 

EISN-AV15 participation 

The number of laboratories participating in the 2015 antiviral susceptibility EQA (EISN-AV15) is shown in Figure 2, 
alongside the participation data for the previous two EQA panels in 2010 and 2013. After an increase in 
participation in 2013, the number of laboratories reporting antiviral susceptibility results has remained relatively 
stable at approximately 24. The number of laboratories using phenotypic characterisation has increased from 12 to 
18 while the number of laboratories using genotypic characterisation has increased from 20 to 24 since 2010 
(Figure 2).  

The number of laboratories using phenotypic, genotypic or a combination of antiviral susceptibility testing methods 
is shown in Figure 3. Six laboratories used only genotypic analysis while 18 laboratories used a combination of 
genotypic and phenotypic analysis. No laboratory used phenotypic analysis if genetic analysis was not possible.  

Figure 2. Participating laboratories: antiviral susceptibility testing, EISN-AV15 EQA panel 

2010 

2013 

2015 

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Belgium 

Bulgaria 

Croatia 

Cyprus 

Czech Republic 

Denmark 

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External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

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2010 

2013 

2015 

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Finland 

France – Lyon 

France – Paris 

Germany 

Greece – Athens 

Greece–Thessaloniki 

Hungary 

Iceland 

Ireland 

Italy 

Latvia 

Lithuania 

Luxembourg 

Malta 

Netherlands – Bilthoven 

Netherlands – Rotterdam 

Norway 

Poland 

Portugal 

Romania 

Slovak Republic 

Slovenia 

Spain – Barcelona 

Spain – Madrid 

Spain – Valladolid 

Sweden 

UK – Belfast 

UK – Cardif 

UK – Glasgow 

UK – London 

Participating laboratories were identified by a unique anonymised participant ID code (Annex 4). Green shading indicates 
participation in AV15. Grey shading indicates non-participation in the panel (i.e. no results returned or no panel requested). 
Participation over the last three EQA panels (2010, 2013, 2015) is shown. 

12 

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External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Figure 3. Methods used for antiviral susceptibility testing 

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Number of laboratories reporting the use of phenotypic, genotypic or a combination of both techniques for the analysis of the 
EISN-AV15 panel  
Black: phenotypic; dark grey: genotypic and phenotypic; light grey: genotypic 

Figure 4A. Analysis of phenotypic antiviral susceptibility per sample in the AV15-EQA panel 

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H1 [275H/Y] H1 sgp 6B

H1 gp 6

H3 3C.3a

H3 3C.2a

H3 3C

B-Vic [I221L]

B-Yam 3

B-Vic 1A

Overview of AV15 phenotypic results, with the number of laboratories reporting the correct result depicted in colour and incorrect 
results shown with black fill. The number of laboratories reporting results for each sample is shown. Samples are divided and 
colour coded into virus type/subtype. Oseltamivir results are in bold fill and zanamivir results are in hatched fill.  

Results of phenotypic testing 

Eighteen of the 24 (75%) ERLI-Net laboratories that participated in the AV15 panel used phenotypic testing to 
determine the susceptibility of the EQA panel against oseltamivir. Seventeen of the participants also determined the 
susceptibility of the EQA panel to zanamivir. Analysis of the phenotypic results presented by individual laboratories 
(Figure 4A) shows that phenotypic testing was generally accurate. Figure 4B shows the results presented by 
individual laboratories; in total, nine errors were reported; one was associated with a laboratory using the NA-Star 

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TECHNICAL REPORT 

assay which failed to detect the mixed NI/HRI population of A(H1N1) due to the NAI mutation H275Y. Three 
laboratories incorrectly reported ‘NI’ for zanamivir on the influenza B NA-I221L sample. The remaining five errors 
were with wild-type samples, one with an A(H3N2) sample and four with influenza B specimens. 

Two fundamental assay platforms can be used for phenotypic testing: chemiluminescence-substrate-based assays 
(e.g. NA-Star and NA XTD Kit) and fluorescent-substrate-based assays (e.g. MUNANA in-house method and NA 
Fluor Kit). Figure 5 represents the number of laboratories using each of the assay formats; 14 use fluorescent-
substrate-based assays while four laboratories use chemiluminescence assays.  

Figure 4B. Individual laboratories results for phenotypic antiviral susceptibility testing 

A(H1N1)pdm09 

A(H1N1)pdm09 
sgp 6B 

A(H1N1)pdm09 
gp 6 

A(H3N2) 3C.3a 

A(H3N2) 3C.2a 

A(H3N2) 

B-Vic [I2221L] 

B-Yam 3 

B-Vic 1A 

Score  Out of 

D

I

t
n
a
p
i
c
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r
a
P

75 

1174 

1299 

1323 

1456 

1534 

1643 

2001 

2126 

2271 

3442 

4213 

r
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RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

HRI 

HRI 

RI 

RI 

r
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NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

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NI 

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NI 

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NI 

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NI 

NI 

NI 

NI 

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NI 

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NI 

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NI 

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NI 

NI 

NI 

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NI 

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NI 

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NI 

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NI 

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RI 

NI 

NI 

NI 

NI 

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HRI 

HRI 

RI 

HRI 

HRI 

RI 

HRI 

HRI 

HRI 

HRI 

HRI 

HRI 

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RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

RI 

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NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

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NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

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NI 

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NI 

NI 

NI 

NI 

NI 

NI 

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NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

NI 

2 

2 

8 

9 

9 

9 

5 

8 

9 

9 

8 

9 

2 

2 

8 

9 

9 

9 

5 

9 

9 

9 

8 

9 

Above: Phenotypic antiviral susceptibility testing, MUNANA assay 

A(H1N1)pdm09 

A(H1N1)pdm09 
sgp 6B 

A(H1N1)pdm09 
gp 6 

A(H3N2) 3C.3a 

A(H3N2) 3C.2a 

A(H3N2) 

B-Vic [I2221L] 

B-Yam 3 

B-Vic 1A 

Score  Out of 

% 
score 

100 

100 

100 

100 

100 

100 

100 

89 

100 

100 

100 

100 

% 
score 

D

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95 

200 

1159 

1402 

2125 

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RI 

RI 

RI 

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2276 

HRI 

NI 

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NI 

NI 

NI 

NI 

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NI 

NI 

NI 

NI 

NI 

r
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NI 

NI 

NI 

NI 

r
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HRI 

HRI 

HRI 

HRI 

HRI 

HRI 

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NI 

NI 

RI 

NI 

RI 

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NI 

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RI 

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NI 

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NI 

NI 

NI 

NI 

r
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RI 

NI 

HRI 

NI 

NI 

r
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NI 

NI 

RI 

NI 

6 

1 

9 

6 

9 

9 

9 

2 

9 

9 

9 

9 

67 

50 

100 

67 

100 

100 

Above: Phenotypic antiviral susceptibility testing, other assays  

HRI: highly reduced inhibition, RI: reduced inhibition, NI: normal inhibition 

Participating laboratories are identified by a unique anonymised participant ID code. Oseltamivir and zanamivir interpretations are 
presented per panel sample for each laboratory that returned results. Shaded cells indicate incorrect or incompletely correct 
results. Blacked out cells indicate that no result was submitted. The scoring system used was as follows: a maximum of one point 
was awarded for each sample, irrespective of whether the participating laboratory tested for both oseltamivir and zanamivir, or 
oseltamivir alone. One point was deducted for each incorrect answer.  

8 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Figure 5. Assay platforms used for phenotypic testing 

NA XTD Kit
NA-Star
NA Fluor Kit
MUNANA in-house

1

3

2

12

20

18

16

14

12

10

8

6

4

2

0

s
e
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a
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b
a

l

f
o
r
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b
m
u
N

Number of laboratories using each of the assay platforms for phenotypic antiviral susceptibility testing. Blue fill denotes 
fluorescence-based assays (MUNANA and NA Fluor); black fill denotes chemiluminescence (NA-Star and NA-XTD).  

Of a total of 88 samples tested by 12 laboratories with the MUNANA assay, only one error was recorded (1.1% of 
all tests); five errors were recorded out of a total of 11 samples tested by the two laboratories which used NA Fluor 
(45.5%); three errors were recorded out of a total of 27 samples tested by the three laboratories which used NA-
STAR (11.1%); one laboratory tested a total of nine samples with the NA XTD kit and reported no errors.  

As previously stated, one of the three laboratories that used NA-Star encountered errors with a sample that 
contained a mixed population of NI/HRI viruses. The reduced sensitivity of the NA-Star assay for mixed-phenotype 
samples had previously been noted. 

Genotypic testing for NA gene substitutions 

Twenty-four laboratories (100%) participated in at least one aspect of the genotypic testing. A correct genotypic 
characterisation was defined as results obtained through an appropriate test with appropriate interpretation. Where 
present, amino acid substitutions associated with reduced inhibition must be correctly identified and reported, 
which requires an appropriate assay and interpretation.  

Participants were not given a score if a result was over-interpreted. For example, the detection of H275 in an 
A(H1N1)pdm09 sample by single nucleotide polymorphism (SNP) PCR can only be interpreted as ‘no interpretation’ 
for oseltamivir susceptibility because we do not know what other amino acid substitutions might be present. 
Laboratories that only use pyrosequencing or SNP PCR are therefore more restricted in the interpretation of results. 
Participants were also asked to identify the amino acid substitutions that they considered important for antiviral 
susceptibility. 

Figure 6 provides an overview of the laboratories which reported genetic results for each sample in the EISN-AV15 
panel; the figure also indicates whether the antiviral susceptibility interpretation for oseltamivir and zanamivir was 
correct. Annex 3 shows the raw data by individual laboratory and the technique used to analyse the sample and 
any amino acid substitutions associated with (highly) reduced inhibition (AARI, AAHRI). If the sample contained no 
amino acid substitution previously associated with highly reduced (AANI), this is also mentioned.  

9 

 
 
 
 
 
 
 
 
 
 
  
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Approximately 15 laboratories reported antiviral susceptibility data for the influenza A(H3) and influenza B samples. 
Over 20 laboratories reported data for the influenza A(H1) samples, but the number of errors increased with the 
number of laboratories which over-interpreted SNP and pyrosequencing results for A(H1N1) samples where no 
amino acid substitutions associated with (highly) reduced inhibition had been detected. 

Figure 6. Genotypic characterisation of antiviral susceptibility per sample in the EISN-AV15 EQA 

s
e

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H1

H1 sgp 6B H1 gp 6 H3 3C.3a H3 3C.2a

H3

B-Vic

B-Yam

B-Vic

Overview of AV15 genotypic results, with the number of laboratories reporting the correct result depicted in colour and incorrect 
results shown with black fill. The number of laboratories reporting results for each sample is shown. Samples are divided and 
colour coded into virus type/subtype. Oseltamivir results are in bold fill and zanamivir results are in hatched fill.  

A correct genotypic characterisation is defined as results obtained through an appropriate test with appropriate interpretation. 
Where present, amino acid substitutions associated with reduced inhibition must be correctly identified.  

To determine whether the technical ability of the network has improved, we compared the ability of laboratories to 
detect NAI-associated nucleotide mutation in a sample containing mixed NI/HRI viruses. The last three EQA panels 
all contained a similar sample, i.e. a mixed population of A(H1N1)pdm09 virus containing the NAI-associated 
nucleotide mutation H275Y. The number of laboratories returning results increased from 20 in 2010 to 24 in 2013 
and then decreased to 23 in 2015. Figure 7 shows the number of laboratories which detected 275H/Y within a 
mixed virus population. The percentage of laboratories which detected 275H/Y within a mixed virus population 
increased from 45% in 2010 to 71% in 2013 and then to 90% in 2015. The proportion of laboratories who were 
able to detect H275 genotype associated with AANI for this mixed sample dropped from 20% in 2010 to 13% in 
2013 and then to 0% by 2015. Together these results suggest that that the quality of genetic analysis has 
improved over the last three EQA panels. 

10 

 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Figure 7. Comparison of the analysis and interpretation for relatively conserved A(H1N1)pdm09 
samples containing mixed populations of NAI NI and RI viruses across three EQA panels: number and 
proportion of correctly interpreted genotypic results from similar A(H1N1)pdm09 275H/Y samples 
tested in 2010, 2013 and 2015  

Detection of 275H/Y mix

275Y

275H/Y

275H

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25

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0

2010

2013

2015

Number of laboratories reporting either 275Y or 275H/Y (AARI/AAHRI) or 275H (AANI).  
Sample compositions:  
2010: A/England/1434/2009 and A/California/7/2009 
2013: A/England/428 and A/England/356 mix 
2015: A(H1N1)pdm09 mixed 275H/Y 

Training 

Three wet-laboratory training courses covering the techniques of sequencing and bioinformatics tools were held in 
November 2010, November 2011 and October 2013. The ability to sequence the NA gene is fundamental to the 
accurate interpretation of NAI susceptibility; especially in non-A subtypes where SNP and pyrosequencing assays 
are constrained by more limited interpretations. A wet-laboratory course and a webinar on antiviral susceptibility 
monitoring were held in July 2011 and January 2015, respectively, and an additional webinar was held in January 
2016. Both webinars discussed the results from the 2013 and 2015 EISN-AV EQA panels and included extensive 
discussions on issues such as over-interpretation of molecular testing results. A full list of all training activities can 
be found in Annex 5.  

11 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Discussion and conclusion  

In the 2015 EQA, participating laboratories showed a reasonable level of competence with regard to antiviral 
susceptibility testing. Twenty-four laboratories participated (out of a potential 38), which represents 63% of the 
network laboratories invited to join the EQA exercise – an increase compared to 2010.  

The panel contained a range of samples encompassing both wild-type strains and samples with amino acid 
substitutions affecting NAI susceptibility most likely to be encountered during surveillance. The panel also 
represented a diverse selection of type/subtype, including influenza A(H1N1)pdm09, A(H3N2), B(Victoria) and 
B(Yamagata). It also included a range of possible phenotypes represented by samples with NI, RI and HRI to both 
oseltamivir and zanamivir. As participants had the option to use phenotypic and/or genotypic testing, samples for 
addressing quality for all possible techniques for antiviral susceptibility testing were available in the AV15 EQA 
panel. 

Eighteen laboratories used phenotypic testing on the EQA panel for oseltamivir susceptibility, and seventeen for 
zanamivir susceptibility; as phenotypic testing can identify novel resistance mechanisms it is encouraging that 75% 
of the network laboratories returning antiviral susceptibility results can use this testing method.  

Neuraminidase enzyme inhibition assays have a second benefit for laboratories because the neuraminidase enzyme 
activity measuring component of the assay can be used to detect positive virus isolation from cultures, especially 
with influenza A(H3) specimens that might fail in the traditionally used haemagglutination inhibition assay.  

The fact that 18 laboratories used phenotypic testing in 2015 represents an increase from the number of 
laboratories using phenotypic testing in 2010 (12) and 2013 (17). A number of laboratories only tested the 
inactivated samples, which were distributed in sufficient quantity for direct analysis, but did not test samples that 
required prior virus isolation and propagation. In some cases this was due to failed virus isolation whereas in other 
examples this appeared to be due to specific sample processing workflows in the laboratory.  

Overall, phenotypic testing was very accurate (Figure 4), with only a single error recorded for the A(N1N1)pdm09 
sample containing a mixed population of NI and HRI viruses. This error was reported by a laboratory using a 
chemiluminescent-based assay (NA-Star), which may explain the mistake. Fourteen of the 18 laboratories (78%) 
that performed phenotypic testing used fluorescence-based assays, which are more sensitive at detecting mixed 
populations of NI and RI viruses within a sample (Figure 5). Seven of the nine phenotypic errors were related to 
interpretation of influenza B samples, with three errors associated with incorrect interpretation of zanamivir 
susceptibility for influenza B virus carrying NA I221L mutation. Of the remaining five errors in ‘wild-type’ samples, 
one was attributed to an A(H3) sample while the remaining four were in influenza B samples. A combination of 
incorrect interpretation and IC50 fold-changes close to the NI/RI threshold (Annex 1) appears to have caused the 
errors. 

Genotypic analysis was generally of a satisfactory standard. Unlike phenotypic testing, where the number of 
laboratories returning results remained stable regardless of the virus type, results for genotypic testing fluctuated 
depending on the virus type. Fifteen to 16 laboratories returned genotypic results for samples that contained the 
influenza A(H3) and B viruses, slightly more than for phenotypic testing. Even more laboratories (21) returned 
results for the samples containing influenza A virus, which probably reflects the ease of performing some of the 
SNP-based assays available for influenza A virus.  

Concerns have been raised that the quality of data uploaded to TESSy could be compromised by the over-
interpretation of genotypic data. For this reason, strict marking rules were employed to point out earlier over-
interpretations.  

It is encouraging that only 11% of influenza B and 12% of influenza A(H3N2) virus genotypic results were 
incorrect. This number increased to 20% for the samples that contained influenza A(H1N1) virus, highlighting the 
problem of over-interpretation of SNP and partial sequencing assay results.  

Two training webinars addressed over-interpretation of genotypic results, particularly when only partial genetic 
information is available. Although the number of errors in the reported genotypic results is still too high, 
interpretations seem to have improved compared to 2013. Other training activities delivered through the 
framework contract addressed sequencing and genetic data analysis (Annex 5), techniques that are essential for 
successful antiviral analysis by whole or partial gene sequencing. We believe that these training activities 
contributed towards a general improvement in the network’s capability and capacity to perform antiviral testing; 
however, directly linking training to improvements is always difficult. 

As the aim of the first antiviral susceptibility EQA in 2010 differed from later EQAs, it is difficult to compare global 
genotypic results. In 2010, the focus was on evaluating whether participating laboratories could apply genotypic 
methods to detect amino acid substitutions affecting NAI susceptibility. In 2013 and 2015, the focus shifted to 
evaluating the interpretation of the genotypic results; particularly whether participating laboratories had a sound 
knowledge of the methodological limitations, especially of those methods targeting SNPs as opposed to 

12 

 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

full segment length sequencing. Common to both the 2010, 2013 and 2015 exercises was the inclusion of a sample 
containing a mixture of oseltamivir HRI (H275Y) and NI viruses. A comparison of reporting on this sample type 
across the three panels provided an indication of how the technical ability of the network has developed (Figure 8). 
The number of laboratories returning genotypic results for this sample has increased since the first EQA panel. The 
proportion of laboratories that detected the 275H/Y mixed amino acid substitution increased from 45% (2010) to 
71% (2013) and reached 91% in 2015. This is a significant improvement in capability because samples with a 
(highly) reduced inhibited virus quasispecies are a common scenario for laboratories which receive samples from 
patients as part of a surveillance programme. 

The 2015 EISN-AV EQA panel has provided evidence of the continued improvements in the technical capacity to 
perform both phenotypic and genotypic antiviral testing across the ERLI-Net network. The quality assessment has 
confirmed the gradual improvements in the quality of genotypic data reported to the TESSy system.  

There is, however, further work required, particularly with regard to the limitations of specific assays and over-
interpretation of results. Training courses to address this issue were already held, but need to be repeated within 
laboratories to ensure a unified and robust level of genotypic interpretation. 

13 

 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Recommendations 

Phenotypic characterisation 

 

 

Eighteen laboratories utilised phenotypic characterisation; an increase in this number would arguably be 
beneficial for ERLI-Net. Either method-specific training courses or twinning activities may help increase the 
number of laboratories using this technique. 
A number of laboratories incorrectly interpreted zanamivir IC50 data for samples containing influenza B 
virus, suggesting that a refresher webinar might be beneficial for data interpretation. 

Genotypic characterisation 

Two webinar theoretical training courses on genotypic data interpretation and TESSy reporting were held. 
Improvements have been seen, however the message needs further reinforcement: 

 

 

 

The use of appropriate assays; SNP-based assays may be suitable for screening of A(H1N1)pdm09 because 
the majority of HRI viruses have H275Y) or A(H3N2) because the majority of HRI viruses have R292K or 
E119V. SNP is less appropriate for influenza B viruses due to the number of different amino acid 
substitutions which have been described to impact NAI susceptibility, all of which occur infrequently. 
Interpretation of genotypic data without over-interpretation; if SNP-based data or partial sequencing data 
are used, interpretations for wild-type viruses are not possible. 
Data reporting; if reporting a HRI/RI virus, the associated amino acid substitutions must also be reported as 
soon as possible, especially if the sequencing is performed by a third party. 

Training courses should be delivered as a webinar training sessions and supplemented by written material on the 
extranet.  

14 

 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

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2.  Wold Health Organization. Laboratory methodologies for testing the antiviral susceptibility of influenza viruses: 

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Virol. 2013 Mar;56(3):212-8. 

14. Jonges M, Liu WM, van der Vries E, Jacobi R, Pronk I, Boog C, et al. Influenza virus inactivation for studies of 

antigenicity and phenotypic neuraminidase inhibitor resistance profiling. J Clin Microbiol. 2010 Mar;48(3):928-40. 

15. European Centre for Disease Prevention and Control. External quality assessment for influenza antiviral 

susceptibility for the European Reference Laboratory Network for human influenza – 2013. Stockholm: ECDC; 
2014. Available from: http://ecdc.europa.eu/en/publications/Publications/influenza-EQA-antiviral-susceptibility.pdf  

16. European Centre for Disease Prevention and Control. External quality assessment scheme for influenza virus 
detection, isolation and culture for the European Reference Laboratory Network for Human Influenza – 2013. 
Stockholm: ECDC; 2014. Available from: http://ecdc.europa.eu/en/publications/Publications/influenza-virus-
detection-isolation-culture-EQA-2013.pdf  

15 

 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Annex 1. Definition of phenotypic 
classification  

Category 

Fold IC50 change* 

Type A viruses 

Type B viruses 

Normal inhibition (NI) 

Reduced inhibition (RI) 

Highly reduced inhibition (HRI) 

<10 

10–100 

>100 

<5 

5–50 

>50 

* Fold change against the median/mean IC50 for the (sub)type, previous or current season, after removal of obvious outliers, or 
against a known wild type virus of the same subtype. 

Annex 2A. Oseltamivir phenotypic IC50 
results presented by laboratories 

16 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Individual laboratories’ IC50 (nM) for each sample of the AV15 panel are shown. Interpretation based on the IC50 in comparison 
to controls is indicated by the colour of the data point (red; RI/HRI or green; NI). 

17 

 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Annex 2B. Zanamivir phenotypic IC50 results 
presented by laboratories 

18 

 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Individual laboratories’ IC50 (nM) for each sample of the AV15 panel are shown. Interpretation based on the IC50 in comparison 
to controls is indicated by the colour of the data point (red; RI/HRI or green; NI). 

19 

 
 
 
 
 
 
 
 
 
 
 
  
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Annex 3A. Genotypic results presented by 
individual laboratories – influenza 
A(H1N1)pdm09 samples 

Participant ID 

Method 

NucAA range 

NA 
mutation 

Oseltamivir 

Zanamivir 

points 

out 
of 

EISN_AV15-01 

Score 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

Full gene sequencing 

117; 119; 136; 151; 155; 199; 223; 247; 275; 293; 295; 
313; 334; 427 

H275Y 

AAHRI 

AANI 

SNP 

SNP 

SNP, partial gene 
sequencing 

Full gene sequencing 

- 

Full gene sequencing 

SNP 

Full gene sequencing 

Full gene sequencing 

Partial gene sequencing 

Full gene sequencing 

Full gene sequencing, 
pyrosequencing 

275 

H275Y 

275H/Y 

AARI 

H275Y 

AAHRI 

275H/Y and 1-339 

275H/Y 

AAHRI 

1-305 

465 

14-469 

0-471 AA 

262-320 

1-457 aa 

275H/Y 

AAHRI 

- 

- 

275H/Y 

AAHRI 

275H/Y 

AARI 

275H/Y 

AAHRI 

119E, 275Y 
(mixed H/Y) 

275H/Y 

275H/Y 

AARI 

AAHRI 

AAHRI 

No 
interpretation 

AANI 

AANI 

AANI 

- 

AANI 

No 
interpretation 

AANI 

AANI 

AANI 

AANI 

Complete NA reading frame, focused on  
known resistance sites  
275 

275Y 

AAHRI 

AANI 

2 

3 

1 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

1643 

Full gene sequencing 

1-462 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

SNP, partial gene 
sequencing 

Full gene sequencing 

SNP 

SNP 

SNP, full gene sequencing 

SNP 

SNP, full gene sequencing 

Partial gene sequencing 

SNP, full gene sequencing 

SNP 

275 position only and range covering all known aa 
substitutions previously associated with reduced antiviral 
susceptibility: 19-456 

1-469 

275 SNP test 

1-470 

H275Y H1N1pdm09 

275 and full gene 

35-462 and 35-462 

275H; 275Y 11-466 

275H 

116V; 119E; 
136Q; 
155Y; 
199D; 223I; 
247S; 262K; 
275H/Y; 
295N 

AAHRI 

AANI 

3 

3 

275H/Y 

AAHRI 

AANI 

275H/Y 

AARI 

AANI 

H275Y 

AAHRI 

274Y 

275H/Y 

275Y 

AAHRI 

AAHRI 

AAHRI 

mix 275H/Y 

AANI 

275 H/Y 

275H/Y 

275H/Y 

AAHRI 

AAHRI 

AARI 

No 
interpretation 

Not tested 

AANI 

Not tested 

AANI 

AAHRI 

AANI 

AANI 

3 

3 

2 

1 

3 

1 

2 

2 

3 

2 

3 

3 

3 

2 

3 

2 

3 

3 

3 

3 

20 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

EISN_INF15-06 

Score 

NucAA range 

NA 
mutation 

Oseltamivir 

Zanamivir 

points  out of 

Participant ID 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

Method 

Full gene 
sequencing 

SNP 

SNP 

SNP, full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing, 
pyrosequencing 

Full gene 
sequencing 

117;119;136;151;155;199;223;247;275;293;295;313;334;427 

I117M 

AANI 

AANI 

275 

H275Y 

275 1-470 

1-305 

1-469 

465 

14-469 

0-471 AA 

262-320 

1-457 aa 

None 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

None 

AANI 

119E, 275H 

AANI 

None 

AANI 

None 

AANI 

No 
interpretation 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

Complete NA reading frame, focused on known resistance 
sites275 

275H 

AANI 

AANI 

1-462 

116V; 119E; 
136Q; 155Y; 
199D; 223I; 
247S; 262K; 
275H; 295N 

AANI 

AANI 

SNP, partial gene 
sequencing 

275 position only and range covering all known aa substitutions 
previously associated with reduced antiviral susceptibility: 1-345 

None 

AANI 

AANI 

Full gene 
sequencing 

- 

SNP 

SNP, full gene 
sequencing 

SNP 

SNP 

Partial gene 
sequencing 

SNP, full gene 
sequencing 

SNP 

1-469 

1-470 

H275Y H1N1pdm09 

275 

35-462 

275H; 275Y and  11-466 

275H 

- 

NO 274Y 

No 

275H 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

Not tested 

- 

Not tested 

AANI 

Not tested 

AANI 

AANI 

AANI 

3 

2 

1 

3 

3 

3 

3 

3 

3 

1 

3 

3 

3 

3 

2 

1 

3 

1 

1 

3 

3 

1 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

2 

2 

3 

3 

3 

21 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Participant ID 

Method 

NucAA range 

NA 
mutation 

Oseltamivir 

Zanamivir 

points 

out 
of 

EISN_INF15-07 

Score 

Full gene sequencing 

117;119;136;151;155;199;223;247;275;293;295;313;334;427 

None 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

SNP 

SNP 

SNP, full gene sequencing 

Full gene sequencing 

Full gene sequencing 

Full gene sequencing 

- 

Full gene sequencing 

Full gene sequencing 

Partial gene sequencing 

Full gene sequencing 

275 

H275Y 

275 1-470 

1-305 

1-469 

465 

14-469 

0-471 AA 

262-320 

1-457 aa 

Full gene sequencing, 
pyrosequencing 

Complete NA reading frame, focused on known resistance 
sites275 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

No 
interpretation 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

3 

2 

1 

3 

3 

3 

3 

3 

3 

1 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

AANI 

AANI 

3 

3 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

Not tested 

- 

Not tested 

AANI 

Not tested 

AANI 

AANI 

AANI 

3 

2 

1 

3 

1 

1 

3 

3 

1 

3 

3 

2 

3 

2 

2 

3 

3 

3 

None 

- 

None 

119E, 275H 

None 

None 

275H 

116V; 
119E; 
136Q; 
155Y; 
199D; 223I; 
247S; 
262K; 
275H; 295N 

None 

- 

No 274Y 

No 

275H 

1643 

Full gene sequencing 

1-462 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

SNP, full gene sequencing 

275 position only and  1-468 

Full gene sequencing 

- 

SNP 

SNP, full gene sequencing 

SNP 

SNP 

Partial gene sequencing 

SNP, full gene sequencing 

SNP 

1-469 

1-470 

H275Y H1N1pdm09 

275 

35-462 

275H; 275Y 12-466 

275H 

22 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Annex 3B. Genotypic results presented by 
individual laboratories – influenza 
A(H3N2)pdm09 samples 

Participant ID 

EISN_INF15-02 

Score 

NucAA range 

NA mutation 

Oseltamivir 

Zanamivir 

points 

out of 

119;136;148;151;222;224;245;246;247;248;276;292;294;371 

None 

Method 

Full gene 
sequencing 

SNP 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

SNP,Full gene 
sequencing 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

- 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

119, 292 

1-470 

1-440 

469 

15-460 

0-471 AA 

15-342 

1-457 aa 

AANI 

AANI 

- 

AANI 

AANI 

- 

AANI 

No 
interpretation 

- 

AANI 

AANI 

- 

AANI 

AANI 

- 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

- 

- 

- 

None 

119E, 292R 

AANI 

None 

None 

AANI 

AANI 

Complete NA reading frame, focused on known resistance 
sites 

1-463 

AANI 

AANI 

AANI 

AANI 

119E; 136Q; 
151D; 152R; 
222I; 224R; 
226Q; 276E; 
292R; 294N; 371R 

119 and 292 position 1-469 

None 

AANI 

AANI 

1-469 

1-470 

Full gene 

1-469 

No PCR amplification 

- 

- 

- 

No 

- 

AANI 

Not tested 

- 

- 

- 

- 

AANI 

AANI 

- 

AANI 

AANI 

- 

AANI 

AANI 

No 
interpretation 

No interpretation 

- 

- 

3 

2 

3 

3 

3 

3 

3 

1 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

23 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Participant ID 

EISN_INF15-04 

Score 

Method 

NucAA range 

NA mutation 

Oseltamivir 

Zanamivir  points 

Full gene 
sequencing 

119; 136; 148; 151; 222; 224; 245; 246; 247; 248; 276; 292; 
294; 371 

T148K; D151G/N 

AANI 

AANI 

out 
of 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

3 

3 

3 

2 

119, 292 

1-469 

1-440 

469 

15-460 

0-471 AA 

- 

- 

148K 

- 

None 

AANI 

- 

No 
interpretation 

- 

AANI 

AANI 

AANI 

AANI 

- 

- 

AANI 

AANI 

3 

3 

- 

- 

AANI 

AANI 

None; sample did not amplify 

No 
interpretation 

No interpretation 

119E, 292R 

AANI 

AANI 

1-457 aa 

None 

AANI 

AANI 

Complete NA reading frame, focused on  
known resistance sites 

1-463 

119E; 136Q; 151D; 
152R; 222I; 224R; 226Q; 
276E; 292R; 294N; 371R 

AANI 

AANI 

AANI 

AANI 

119 and 292 position  and   1-469 

None 

AANI 

AANI 

1-469 

1-470 

1-469 

No PCR amplification 

- 

- 

- 

- 

No 

- 

AANI 

Not tested 

- 

- 

- 

- 

AANI 

AANI 

3 

3 

- 

- 

- 

- 

AANI 

AANI 

3 

3 

No 
interpretation 

No interpretation 

- 

- 

SNP 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

SNP, full gene 
sequencing 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

24 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Participant ID 

Method 

NucAA range 

NA 
mutation 

Oseltamivir 

Zanamivir 

points  out of 

EISN_INF15-05 

Score 

Full gene 
sequencing 

119; 136; 148; 151; 222; 224; 245; 246; 247; 248; 276; 292; 
294; 371 

T148I; 
D151G/N 

AANI 

AANI 

AANI 

No interpretation 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

SNP 

- 

Partial gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

SNP,Full gene 
sequencing 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

119, 292 

1-343 

1-440 

469 

15-460 

0-471 AA 

- 

- 

148I 

- 

None 

- 

AANI 

AANI 

- 

AANI 

- 

AANI 

119E, 292R, 

AANI 

- 

AANI 

AANI 

- 

AANI 

- 

AANI 

AANI 

None; sample did not amplify 

No interpretation  No interpretation 

1-457 aa 

148T/I 

AANI 

Complete NA reading frame, focused on  
known resistance sites 

AANI 

AARI 

AANI 

1-463 

119E; 136Q; 
151D; 152R; 
222I; 224R; 
226Q; 276E; 
292R; 294N; 
371R 

AANI 

AANI 

3 

3 

119 and 292 position and  1-469 

None 

AANI 

AANI 

3 

2 

1 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

3 

1-469 

1-470 

1-469 

8-469 

- 

- 

- 

- 

No 

- 

AANI 

Not tested 

- 

- 

- 

- 

AANI 

AANI 

3 

3 

- 

- 

AANI 

AANI 

- 

- 

- 

AANI 

AANI 

- 

3 

3 

3 

3 

25 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Annex 3C. Genotypic results presented by 
individual laboratories – influenza B samples 

Participant 
ID 

EISN_AV15-02 

Score 

Method 

NucAA range 

NA mutation 

Oseltamivir 

Zanamivir 

points 

out 
of 

Full gene 
sequencing 

105; 117; 138; 139; 140; 144; 145; 150; 197; 200; 221; 245; 
273; 292; 294; 360; 374; 395; 407; 432 

I221L 

AAHRI 

AARI 

3 

3 

SNP 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Partial gene 
sequencing 

SNP 

- 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

150, 197, 294 

1-467 

- 

- 

- 

AANI 

AANI 

1-430 and 1-430 

I221L 

AAHRI 

AARI 

466 

1-498 

0-467 AA 

17-336 

88-244 aa 

- 

221L 

- 

221L 

- 

- 

AAHRI 

AARI 

- 

- 

AAHRI 

AARI 

150R, 197D, 221L 

AAHRI 

AARI 

221L 

AAHRI 

AARI 

I221L 

AAHRI 

AARI 

Complete NA reading frame, focused on known resistance sites 

221L 

AAHRI 

AARI 

1-493 

117E; 150R; 
197D; 221L; 
292R; 294N; 
374R; 407G 

AAHRI 

AARI 

Range covering all known aa substitutions previously associated 
with reduced antiviral susceptibility: 111-431 

I221L 

AAHRI 

AARI 

42-191 

AANI 

Not tested 

152, 198 and 222 SNP tests 

R152; D198; 
I222L 

AAHRI 

AARI 

- 

- 

- 

1- 466 

I221L 

AAHRI 

AARI 

1-466 

1-467 

- 

- 

- 

- 

- 

- 

221L 

AAHRI 

AAHRI 

I221L 

AAHRI 

AARI 

- 

- 

- 

0 

3 

3 

3 

3 

3 

3 

3 

3 

3 

0 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

3 

3 

3 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

26 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Participant 
ID 

EISN_INF15-01 

Score 

Method 

NucAA range 

NA mutation 

Oseltamivir 

Zanamivir 

points 

Full gene 
sequencing 

105; 117; 138; 139; 140; 144; 145; 150; 197; 200; 221; 245; 
273; 292; 294; 360; 374; 395; 407; 432 

None 

AANI 

AANI 

75 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

1432 

1456 

1534 

1643 

2001 

2125 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

SNP 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

- 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Full gene 
sequencing 

Partial gene 
sequencing 

Partial gene 
sequencing 

- 

- 

Full gene 
sequencing 

- 

- 

Full gene 
sequencing 

Full gene 
sequencing 

- 

150, 197, 294 

1-467 

1-430 and 1-430 

1-305 

466 

1-498 

0-467 AA 

17-197 

1-467 aa 

42-191 

1- 466 

1-466 

1-467 

Complete NA reading frame, focused on known resistance sites 

AANI 

AANI 

1-493 

117E; 150R; 
197D; 221I; 
292R; 294N; 
374R; 407G 

AANI 

AANI 

Range covering all known aa substitutions previously 
associated with reduced antiviral susceptibility: 111-431 

None 

AANI 

AANI 

AANI 

- 

No inter-
pretation 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

- 

AANI 

AANI 

No 
interpretation 

No interpretation 

- 

- 

None 

150R, 197D, 221I 

AANI 

AANI 

None 

None 

AANI 

AANI 

AANI 

AANI 

out 
of 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

2 

3 

3 

3 

3 

3 

1 

3 

3 

3 

3 

0 

- 

- 

- 

- 

AANI 

Not tested 

- 

- 

- 

- 

AANI 

AANI 

3 

3 

- 

- 

- 

- 

No 

AANI 

AANI 

AANI 

AANI 

- 

- 

- 

3 

3 

3 

3 

27 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Participa
nt ID 

EISN_INF15-08 

Score 

Method 

NucAA range 

NA mutation 

Oseltamivir 

Zanamivir 

points 

75 

Full gene sequencing 

105; 117; 138; 139; 140; 144; 145; 150; 197; 200; 221; 245; 
273; 292; 294; 360; 374; 395; 407; 432 

None 

AANI 

AANI 

- 

- 

None 

150R, 197D, 221I 

None 

None 

117E; 150R; 
197D; 221I; 
292R; 294N; 
374R; 407G 

95 

117 

200 

1159 

1174 

1262 

1299 

1323 

1402 

SNP 

- 

Full gene sequencing 

Full gene sequencing 

Full gene sequencing 

Full gene sequencing 

- 

Full gene sequencing 

Full gene sequencing 

1432 

Partial gene sequencing 

Full gene sequencing 

1456 

1534 

150, 197, 294 

1-467 

1-430 

1-466 

466 

1-498 

0-467 AA 

17-333 

1-449 aa 

Full gene sequencing  Complete NA reading frame, focused on known resistance sites 

1643 

Full gene sequencing 

1-493 

2001 

Partial Gene sequencing 

Range covering all known aa substitutions previously associated 
with reduced antiviral susceptibility: 111-431 

None 

2125 

Partial gene sequencing 

42-191 

2126 

2253 

2271 

2272 

2276 

2306 

3442 

4213 

- 

- 

Full gene sequencing 

- 

Full gene sequencing 

Full gene sequencing 

Full gene sequencing 

- 

1-466 

Full gene 

1-466 

17-467 

- 

- 

- 

No 

- 

out 
of 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

2 

3 

3 

3 

3 

3 

3 

1 

3 

3 

3 

3 

1 

3 

3 

3 

3 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

No 
interpretatio
n 

- 

AANI 

AANI 

AANI 

AANI 

- 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

AANI 

- 

- 

AANI 

- 

AANI 

AANI 

AANI 

- 

AANI 

Not tested 

- 

- 

AANI 

- 

AANI 

AANI 

AANI 

- 

Participating laboratories are identified by a unique anonymised participant ID code. Participants’ genotypic assay types are 
categorised as ‘Sequencing’, ‘partial gene sequencing’, ‘SNP/Pyro’ or both SNP and sequencing ‘Both’. Oseltamivir and zanamivir 
interpretations are presented per panel sample for each laboratory that returned results. Shaded cells indicate incorrect result. 
Scores per sample are indicated to the right of each drug interpretation column. 

28 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TECHNICAL REPORT 

External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015 

Annex 4. List of participating laboratories 

Austria  
Belgium 
Czech Republic  
Denmark 
Finland  
France  
France  
Germany 
Greece  
Greece  
Hungary  
Ireland  
Italy 
Latvia 
Netherlands 
Netherlands 
Norway 
Portugal 
Romania 
Spain 
Spain 
Sweden 
United Kingdom 
United Kingdom 

Vienna 
Brussels 
Prague 
Copenhagen 
Helsinki 
Paris 
Bron Lyon 
Berlin 
Athens 
Thessaloniki 
Budapest 
Dublin 
Rome 
Riga 
Bilthoven 
Rotterdam 
Oslo 
Lisbon 
Bucharest 
Madrid 
Barcelona 
Solna 
London 
Glasgow 

AKH Wien – Medical University of Vienna 
Institute of Public Health 
National Institute of Public Health 
Statens Serum Institute 
National Institute for Health and Welfare 
CNR de la Grippe – Institute Pasteur 
CNR Virus Influenza – HCL Lyon 
Robert Koch Institute 
National Influenza Center for S Greece 
National Influenza Centre for N Greece, Aristotle University of Thessaloniki 
Országos Epidemiológiai Központ 
University College Dublin 
Istituto Superiore di Sanita (NIH) 
National Microbiology Reference Laboratory, NIC of Latvia 
RIVM 
Erasmus MC 
Norwegian Institute of Public Health 
Instituto Nacional de Saúde Doutor Ricardo Jorge 
Cantacuzino Institute 
Instituto de Salud Carlos III 
Hospital Clinic i Provincial de Barcelona 
Folkhälsomyndigheten 
Public Health England 
Gartnavel General Hospital 

29 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
External quality assessment scheme for influenza antiviral susceptibility – ERLI-Net 2015  

TECHNICAL REPORT 

Annex 5. List of training activities 

Country 

Influenza 
surveillance 

Sequencing 
and 
bioinformatics 
tools 

AntiViral 

Sequencing 
and 
bioinformatics 
tools 

Virus culture  Virus culture 

Sequencing 
and 
bioinformatics 
Tools 

Virus 
characterisation 

AntiViral 

NGS 
Bioinformatics 

EQA + season 
start 

Jun 2010 

Nov 2010 

Jul 2011 

Nov 2011 

Nov 2012 

Apr 2013 

Oct 2013 

Dec 2014 

Jan 2015 

Jan 2016 

Jan 2016 

Sweden 

Netherlands-
Rotterdam 

UK – Cardiff 

UK – Glasgow 

Denmark 

Iceland 

Austria 

Belgium 

Finland 

France – Paris 

Germany 

Hungary 

Ireland 

Italy 

Luxembourg 

Norway 

Spain – Madrid 

Spain – Valladolid 

Netherlands – 
Bilthoven 

Czech Republic 

UK – London 

Latvia 

Estonia 

Cyprus 

Greece – Athens 

Greece – 
Thessaloniki 

Malta 

Romania 

Slovak Republic 

Slovenia 

Spain – Barcelona 

Croatia 

Bulgaria 

Portugal 

UK – Belfast 

Lithuania 

France – Lyon 

Poland 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

xx 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

x 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

* 

** 

** 

** 

** 

** 

* 

* 

* 

** 

* 

* 

** 

** 

* 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

** 

Training courses offered to ERLI-Net (CNRL) laboratories. Attendance of a wet training course is marked with an X.  
Webinar training courses are marked with ** for countries who dialled into the live presentation.  
Countries that expressed an interest and received the video of the presentation are marked with an asterisk (*).  

Countries with access to the ECDC extranet can view the recorded presentations online. 

30 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Prevention and Control (ECDC)

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