Saturday, December 18, 2010

News? No. Vaccines with adjuvants induce stronger immune responses, but SAFETY is the issue/ Reuters

Reuters makes big news of a study showing that Glaxo's swine flu vaccine (which contains ASO3 adjuvant) induced a stronger immune response than an unadjuvanted Baxter vaccine.

This is nothing to crow about.  Everyone agrees that adjuvants boost the immune response; the question is how much increased autoimmune illness or other adverse events occur as a result of the adjuvant boost.  Norman Baylor, director of FDA's Office of Vaccine Research and Review, told Science magazine that antigen-sparing strategies [using a cheaper adjuvant to reduce the amount of antigen in vaccine--Nass] benefit populations, not individuals. "You have to think about those trade-offs," Baylor said.

Another issue is whether the "stronger immune response" actually prevents flu in more people.  Data from many studies of flu vaccines show that the vaccines are up to 75% effective at preventing flu, when the vaccine strains match the common circulating flu strain(s).  So far, there is no evidence that adjuvanted vaccines do better than 75%.

Furthermore, flu vaccines do not lead to reduced hospitalizations or complications from influenza (which is what causes flu-related deaths) and there is no evidence adjuvanted vaccines do either.  So the higher levels of antibodies achieved with adjuvanted vaccines may not produce any clinical beneft whatsoever.

Remember, every medical intervention is associated with cost and with risks and benefits. The extent of the benefit must exceed the risk.  That has not been shown for ASO3 or other novel adjuvants.  Reuters can cheerlead all it wants to, but these adjuvants are not ready for prime time.  Until we have a much better idea of the adverse event profile of last year's adjuvanted swine flu vaccines (used in most countries in 2009 but not in the US due to safety concerns) it is premature to use these products in mass vaccination programs.  [A joint FDA-NIH conference on how to study the safety of adjuvants was held in December 2008 and can be accessed here.]

Where are the data from the US and the rest of Europe and Australia on narcolepsy incidence following swine flu vaccinations?  Why have Sweden and Finland seen a steep rise in cases?  What other neurologic disorders, if any, have occurred at increased incidence?  These are only some of the questions that must be answered prior to adopting novel adjuvants for general use.

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