# Presentation: 888965

## U.S. Influenza Surveillance Update, 2007-8 Season

**Joseph Bresee MD**
**Epidemiology and Prevention Branch, Influenza Division, CDC**
**VRBPAC Meeting**
**Feb 21, 2008**
**Gaithersburg, MD**

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## 21 states and the District of Columbia reported sporadic influenza activity

**26 states reported no influenza activity    ****▪   ****3 states reported local activity**

## 33 states and the District of Columbia reported sporadic influenza activity

**13 states reported no influenza activity    ****▪   ****4 states reported local activity**

## 3 states reported no influenza activity    ▪   9 states reported local activity

**3 states reported no influenza activity    ****▪   ****9 states reported local activity**
**5 states reported regional activity**

## 10 states and Puerto Rico reported sporadic influenza activity

**17 states and the District of Columbia reported local activity**
**17 states reported regional activity    ****▪  6 states reported widespread activity**

## 4 states and Puerto Rico reported sporadic influenza activity

**9 states and the District of Columbia reported local activity**
**26 states reported regional activity    ****▪  11 states reported widespread activity**

## 2 states and the District of Columbia reported local activity

**17 states reported regional activity    ****▪  31 states reported widespread activity**

## 1 state and the District of Columbia reported local activity

**Puerto Rico reported sporadic activity**
**5 states reported regional activity    ****▪  44 states reported widespread activity**

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## U.S. WHO/NREVSS Collaborating LaboratoriesNational Summary, 2007-08

**Since Sept 30-**
**14%**** ****of**** ****109,089**** ****specimens tested positive for influenza viruses**
**  ****83% A**
**  ****17% B**
**of 28% ****of A viruses subtyped:**
**-37%**** ****A (H1) viruses**
**-63%**** ****A (H3) viruses**

## U.S. WHO/NREVSS Collaborating LaboratoriesNational Summary, 2007-08

**In most recent week-**
**34%**** of 6,889 specimens tested positive for influenza viruses**
**  ****79% A**
**  ****21% B**
**of 23% of A viruses subtyped:**
**-****11%**** A (H1) viruses**
**-****89%**** A (H3) viruses**

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## Pneumonia and Influenza Mortalityfor 122 U.S. CitiesWeek Ending 02/16/2008

- Epidemic Threshold

- Seasonal Baseline

- Pneumonia and Influenza Mortalityfor 122 U.S. CitiesWeek Ending 02/16/2008

- 2005

- 2006

- 40      50     10      20      30     40       50      10       20      30     40      50     10     20     30     40      50      10      20      30       40       50      10

- 2007

- 2004

- 2008

## Number of Influenza-Associated Pediatric Deaths by Week of Death:  2005-06 season to present

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## Percentage of Visits for ILI & ARI Reportedby Sentinel Providers and BioSense Outpatient Facilities,National Summary

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## EIP Influenza Laboratory-Confirmed Cumulative Hospitalization Rates for Children Aged 0-4 and 5-17 yrs, 2007-2008 and Previous 2 SeasonsSeptember 30 – February 2, 2008

## Seasonal Influenza

- Geographic Spread
- Virus Monitoring
- Mortality
- Outpatient Illness
- Hospitalizations
- Antiviral Resistance

## Oseltamivir resistance, 2007-8 Influenza Season, U.S.

**5.7% (27/471) of influenza isolates tested were oseltamivir-resistant**
**27 (8.1%) of 312 H1N1 resistant (all with H274Y mutation)**
**0 / 76 H3N2**
**0 / 83 B**
**All regions of the country**
**No travel history known for any case**
**No oseltamivir exposure known**
**Apparent typical clinical illness and severity**
**All H1N1 oseltamivir-resistant viruses tested susceptible to zanamivir and adamantanes**
**31% (88/282) influenza A viruses tested resistant to adamantanes**
**99% of H3N2 viruses and 7.2% of H1N1 viruses**

## A (H1N1) oseltamivir resistance – Europe, Canada, Asia(as of 14 February 2008)

- Global *–* 14% (237 / 1703)
- Europe – 20% (202 / 987)
- 13 of 22 countries with resistant H1s
- Asia  - 2.1% (7 / 319)
- 2 of 7 countries (no resistance in Japan)
- Africa – 0% (0 / 18)
- Americas
- Canada – 	6% (8/128)
- Latin America – 	0% (0/9)

**WHO data**

## Oseltamivir resistance – Plans to address

- Enhanced Surveillance
- Increased numbers of viruses for testing
- Collect detailed clinical, epi data on each case
-  Standard reporting form that is sent to SHDs
- Communications
- Talking points and Q&As developed and distributed
- Share materials with international and national partners (e.g. WHO, ECDC, CSTE, APHL, ACIP)
- Press briefings
- Policy
- No change in policy for use of antivirals at this point
- ACIP Influenza WG discussed antiviral policy

## Interim Estimation of Influenza Vaccine Effectiveness During the 2007-08 Season

**CDC partnered to develop capacity to provide annual VE estimates**
**This season, will conduct studies to provide VE estimates during the season**
**Methods**
- Population: People recommended by ACIP to receive annual vaccination
- Outcome:   Medically attended influenza diagnosed by RT-PCR
- Exposure:   Vaccination status confirmed by validated vaccine registry
**Status**
- From Jan 21 through Feb 8, 616 (69%) of 896 eligible patients were tested
- 191 (31%) were PCR-positive for influenza; 144 (75%) of those had influenza A
- Preliminary results indicates vaccine provides
- Some protection against infections with influenza A viruses
- No protection against infections with influenza B viruses
**Plans**
- Continue enrollment
- Type/subtype data pending – for type/subtype-specific analyses
- Report of data during the season

## Draft ACIP Agenda:  Influenza Session Feb 27, 2008

- Influenza vaccine effectiveness among 6-23 month old children, 2005-6 and 2006-7 seasons
- Influenza vaccine strain selections 2008-09
- Oseltamivir-resistant influenza A (H1N1)
- Expanding influenza vaccination recommendations to include all 5-18 year old children
- Influenza vaccination recommendations, 2008
- Vote
- VFC Vote