Early Data Favorable for H5N1 Vaccine from Tissue-Culture Substrate

http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/9805

VIENNA, June 12 -- An H5N1 whole-virus vaccine grown in tissue culture seems both safe and effective in a two-dose regimen against avian influenza, found a clinical trial of nearly 300 volunteers. Action Points
The vaccine was effective in inducing neutralizing antibody at either 7.5 μg or 15 μg doses in a two-dose regimen and worked best without the use of alum adjuvant, Markus Muller, M.D., of Medical University of Vienna, and colleagues reported in the June 12 issue of the New England Journal of Medicine.

The highest neutralizing-antibody response (78.2%) was obtained after the 7.5-μg second dose without adjuvant. This was "equivalent to a rate of seroconversion of 69% and represented an increase by a factor of four or more in the neutralization titer after two doses of vaccine," they wrote.

Those data were "also similar to the levels of immunogenicity reported in a study of an egg-derived whole-virus H5N1 vaccine."

The data also "showed that the whole-virus clade 1-based vaccine can induce a substantial cross-neutralizing response