Additional data from the NIAID trials are forthcoming. However, on the basis of these strong early data, our results are consonant with other reports that a single 15-microgram dose of unadjuvanted 2009 H1N1 influenza vaccine is well tolerated and induces a robust immune response in healthy adults between the ages of 18 and 64. For adults aged 65 and older, the immune response to 2009 H1N1 influenza vaccine is somewhat less robust, as is the case with seasonal influenza vaccines.

We note that the slight discrepancies seen in our trials between the Sanofi Pasteur and CSL Limited vaccines may be due to technical differences in the preliminary measurement of the amounts of antigen in the doses used in the clinical trial lots and the relatively limited numbers of samples studied to date, as well as the fact that our data are drawn from a very early time point after immunization.

NIAID will continue to provide timely updates on these trials as well as those in children and in pregnant women, which began later. We will join colleagues from across HHS for the weekly H1N1 briefing to be held this week at HHS on Friday at 1:00 PM.

Information from the NIAID studies will help inform the development of recommendations for immunization schedules, including the optimal dosage and number of doses for different age groups.

Source: NIH/National Institute of Allergy and Infectious Diseases