Bird flu vaccine with adjuvant shows encouraging results
An avian influenza vaccine including an adjuvant was well tolerated
and initiated an antibody response in over two-thirds of recipients in
a phase I trial published online in The
Lancet (11 May 2006).
The trial involved 300 volunteers who received one of six formulations
of egg-grown, inactivated split-virion influenza (H5N1) vaccine: 7.5µg,
15µg or 30µg, with or without aluminium hydroxide adjuvant.
Volunteers received a two-dose regimen (day 0 and day 21) and immune
response was measured 21 days after each dose.
The researchers found that the adjuvanted 30µg formulation induced
the greatest response rate (67 per cent). Adjuvant did not improve the
response to the lower doses of vaccine. Non-adjuvanted 7.5µg, and
adjuvanted and non-adjuvanted 15µg formulations seroconverted 43
to 44 per cent of
recipients.
All formulations were well tolerated, with no reports of serious adverse
events, severe injection site reactions or febrile episodes, the researchers
say. Most participants reported at least one reaction to the vaccine,
which mainly comprised mild-to-moderate injection site reactions or headache,
they add.
The researchers note that the level of post-vaccination antibodies needed
to achieve protection against mortality and severe disease is unknown,
and limited manufacturing capacity implies the need to adopt dose-sparing
strategies. They observed encouraging results with lower doses of antigen
but further studies are needed, they conclude. |
The
Pharmaceutical Journal
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