Immune Response Strong as H1N1 Influenza Vaccines are Well Tolerated

by Rajashri on Sep 14 2009 8:25 PM

Health experts in the US have revealed that early results from various clinical trials of 2009 H1N1 influenza vaccines in healthy adults seem to be quite encouraging.

The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health in the U.S., has revealed that the early data from these trials suggest that 2009 H1N1 influenza vaccines are well tolerated, and induce a strong immune response in most healthy adults, when administered in a single unadjuvanted 15-microgram dose.

It has even congratulated the companies that have carried out these trials, which it claims are an important part of the ongoing worldwide effort to develop vaccines to protect the public from 2009 H1N1 influenza.

The National Institute of Allergy and Infectious Diseases is also conducting clinical trials of 2009 H1N1 influenza vaccines, produced by Sanofi Pasteur and CSL Limited.

The trials are testing two different dosages-15 micrograms versus 30 micrograms-and evaluating the immune response to one and two doses of these vaccines.

More than 2,800 people are said to be participating in the ongoing NIAID trials of these vaccines.

The institute says that preliminary analyses of early data from its trials align with the recently announced findings, and those to be announced imminently by other companies.

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," the institute said in a press release.

"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," the institute added. (ANI)