Avian influenza vaccine moderately effective
High doses of an experimental subvirion influenza A (H5N1) vaccine can induce immune responses typically associated with protection against influenza in over half of recipients, according to research published
in The New England Journal of Medicine last month (2006;354:1343).
John Treanor, University of Rochester, New York, and colleagues conducted
a
double-blind randomised controlled trial in 451 healthy adults.
The volunteers were given two intramuscular doses of egg-grown, inactivated
subvirion H5 vaccine at doses of 7.5µg, 15µg, 45µg,
90µg or placebo. The two doses were given 28 days apart and after
56 days volunteers were tested for H5 antibody. The researchers found
that only the 90µg dose was associated with antibody responses
in more than half the volunteers (54 per cent). The 45µg dose resulted
in antibody response in 43 per cent. The lower doses were much less immunogenic
(22 per cent and 9 per cent, respectively). The vaccine was generally
well tolerated at all doses, say the researchers.
“The need for a vaccine with a total dose of 180µg would
pose a considerable barrier to rapid production of a supply that would
be adequate
to meet the world’s requirements should a pandemic occur,” the
researchers note. They suggest that dose-sparing approaches, such as
the use of adjuvants and intradermal administration of vaccine, should
be pursued aggressively. |
The
Pharmaceutical Journal
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