Review for 10.1186/1471-230X-11-87 (2011)

Reviewer's report
Title:An Australian Audit of Vaccination Status in Children and Adolescents with
Inflammatory Bowel Disease
Version: 1Date:27 April 2011
Reviewer: Petar Mamula
Reviewer's report:
The manuscript by Crawford et al. reports the results of their assessment of
vaccination rates among children with inflammatory bowel disease in the
Australian state of Victoria from July to November 2007. They used several
instruments in their study: 1) the Australian Childhood Immunization Register,
which contains information on children up to 7 years of age; 2) hospital record
audit for vaccination records; 3) telephone interviews with consenting parents; 4)
primary care physician questionnaires; and 5) review of hospital records for
evidence of obtained serology testing. Of a total of 534 patients in the Victorian
database with inflammatory bowel disease, they randomly selected 101 patients,
of whom 51 had to be excluded, mostly due to lack of response. Of the remaining
subjects, 42 completed interviews. The authors found that 90% of those
interviewed were up-to-date with primary immunizations. However, they found
that only 5% had received a pneumococcal vaccine booster and 10% have ever
received a seasonal influenza vaccine (out of the original total of 101 subjects).
Based on these findings, they submit that vaccination rates among children with
IBD remain low and that additional efforts need to be made to improve
vaccination rates.
Conflicts of interest: Two of the authors (NWC and AGC) declared specific
interactions with corporations that have an interest in vaccine development. The
Murdoch Childrens Research Institute has received conference travel
reimbursement from a corporation for a vaccine conference presentation.
Ethical issues: None. Study was approved by local Human Research Ethics
Committee.
Originality: While this is not the first time in the literature that this topic has been
addressed, it does highlight an important issue in the care of children with
inflammatory bowel disease.
Comments by section
• Abstract
o No specific concerns.
• Background
o Since a significant portion of the readership may not necessarily be very
familiar with how the Australian health care system operates and in order to
better define the study population, this section may benefit from more information
on how IBD patients are managed (i.e., are all managed by pediatric
gastroenterologist, or are some patients managed by their pediatricians? Are any
adolescents seen by adult gastroenterologist? Are there any other pediatric
centers or private gastroenterologists outside of the two mentioned tertiary care
centers that see pediatric patients with IBD?).*
o The second paragraph states that pediatric gastroenterologists are responsible
for recommending vaccinations in IBD patients. Are the vaccinations actually
delivered by pediatric gastroenterologists or by the pediatricians?
• Methods
o This section would benefit from a fuller discussion of the local care environment
managing children with IBD. E.g. how many practitioners are working in the
gastroenterology centers mentioned? Do these centers have vaccination
programs in place for these at-risk populations, or is it up to each individual
practitioner to recommend and implement?*
o If these data were available, the study would have benefited from an
examination of the rate of vaccine-preventable diseases in those who were
vaccinated versus those who were not. Additionally, a comparison to a control
group of non-IBD patients would have strengthened the study.
o The authors mention this in their discussion, but the study was limited by the
fact that they did not survey practitioners about their own vaccination practices.
o Could the authors provide more information about how the sample size
calculation was done? From the text, it appears that 101 subjects were randomly
chosen based on their calculated sample size. Does this number refer to
minimum subjects needed to sufficiently power the study, or is this taking into
account the significant attrition they encountered due to various factors, such as
inability to obtain a response from subjects’ families? It might be useful to
mention the total number of the patients entered in the database in this section
since it is only mentioned in the table.*
• Results
o In paragraph 1, when the authors mention that 39 subjects were on active
therapy at the time of the audit, does this include 5-ASA medications (not listed
later in the sentence), and is this out of the 101 randomly selected subjects, or is
this out of the 42 who eventually completed the survey?*
o Throughout this section, a number of different denominators are used to
calculate percentages, which makes it difficult to compare these numbers.
o In the second paragraph, when the authors state “In those whom a complete
immunization history was obtained…”, what do they mean by this? Does this
refer to subjects who had hospital records, ACIR records, and survey results?*
o In paragraph three, regarding the reasons for not having received an influenza
vaccine, why is it that the percentages do not add up to 100%?*
o In paragraph four, with regard to the hepatitis B vaccination history, how many
of the patients on infliximab had serology, in addition to a positive history of
vaccination obtained?*
o Table 1: What do the asterisks refer to?
o Table 2: What does the asterisk refer to? Not clear if the information about
blood transfusion is helpful (assuming that this is addressing the issue of
transfusions confounding serology results; information here does not allow
discrimination of whether this might have been an issue in these four patients).
o Table 3: Given the many different denominators, it is not clear that this table
adds particularly useful information. We would recommend deleting it.*
o Figure: Could the authors explain why 50 patients were not on the register (i.e.
should not all patients have an ACIR record, even if they were older than 7 years
at the time of the study?)? In the box “Patients Excluded”, the n should equal 51,
not 52.
• Discussion
o Limitations of the study were appropriately addressed.
o Overall, this section would have benefited from a fuller discussion on what
should be done to improve vaccination rates in children with IBD. Less space
could be dedicated to discussing opt-out consent.*
Conclusion: Although the study has a number of limitations that are common for
this type of study, this manuscript adds to our knowledge base regarding
vaccination rates in pediatric IBD, and it is an important reminder of the
deficiencies that continue to exist in adequately protecting this population from
vaccine-preventable diseases.
The comments marked with an asterix are Major Compulsory Revisions.
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.