Wednesday, July 1, 2009

Vaccine safety - preparing for the eventuality

I have posted on the topic of vaccines and vaccine safety before.

Here I want to highlight 2 recent scientific reviews on this topic which I think are important for us to consider as we hurtle down this road towards H1N1 mass vaccination programmes.

The first is a review in 2008, by Dr Fineberg in the Journal of Infectious Diseases (if you want the pdf of the original paper, just email me). This review was done when avian flu was a hot topic, and it draws upon lesson from the 1976 US mass vaccination programme for swine flu which resulted in a national fiasco where 25% of the poulation was vaccinated and no evidence of any pandemic. In the review, Dr Fineberg recalls the 7 features of the swine flu :

1. Overconfidence in theory spun from meager evidence.
2. Conviction fueled by preexisting agendas.
3. Zeal by health professionals to make lay superiors “do the right thing.”
4. Premature commitment.
5. Failure to address uncertainties.
6. Insufficient questioning of implementation prospects.
7. Insensitivity to media relations and to long-term credibility.

....and identifies 7 lessons today that we can learn from that fiasco:

1. Beware of overconfidence in models drawn from meager evidence.
2. Invest in a balanced portfolio of research and contemporary preparedness.
3. Clarify operational responsibilities in the federal government.
4. Refrain from overstatement of objectives and misrepresentation of risk.
5. Strengthen local capacity for implementation.
6. Communicate strategically.
7. Lay the basis for program review.

The second review is just hot off the press in the same august journal, entitled ""Prepandemic" Immunization for Novel Influenza Viruses, "Swine Flu" Vaccine, Guillain-Barré Syndrome, and the Detection of Rare Severe Adverse Events", by Dr Evans and his co-workers. (conclusions abstracted below)

"In summary, the risk of SAEs (serious adverse events) will remain important considerations in developing immunization policies for interpandemic use of novel influenza vaccines and implementing mass immunization programs. These issues are particularly challenging when the risks of severe illness or of a future pandemic are uncertain and, therefore, safety concerns more acute, as is the case in interpandemic vaccination. However, even if an association between SAEs and interpandemic vaccination could be discounted with confidence, the reality is that public perception of a link has the potential to undermine amass vaccination strategy over and above the scientific evidence, as clearly evidenced in the 1976 experience."

I will leave it to you to form your own impressions about our current approaches towards the H1N1 vis a vis the comments contained in these reviews. I would certainly recommend these as compulsory reading for those interested in vaccine safety, and also for our decision makers in MOH who may be contemplating a mass vaccination strategy.

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