Sanofi Pasteur claims H5N1 vaccine breaktrhough
Scientists are claiming a breakthrough in the
battle to produce a vaccine against the deadly H5N1 strain of bird flu. Their
findings were published in an on-line report from The Lancet medical
French scientists from the pharmaceutical company Sanofi Pasteur are
developing a vaccine based on a modified strain of the virus.
experimental vaccine has been produced and has passed its first clinical hurdle,
with a phase one trial involving 300 volunteers proving conclusively that the
vaccine can trigger a safe immune response in people.
is no evidence yet that H5N1 can spread from person-to-person, a reliable
vaccine will be a vital weapon if the virus mutates into a pandemic form. The
virus is highly virulent, with a fatality rate of up to 70%.
Melanie Saville and colleagues reported on an assessment of whether the vaccine
is safe and capable of producing neutralising antibodies in
In the trial, volunteers received one of six vaccine
formulations at various doses with or without the addition of a "helper"
adjuvant compound, aluminium hydroxide.
The scientists found that a
two-dose regimen of 30 micrograms of the vaccine induced the highest antibody
response after 42 days.
Vaccines given with aluminium hydroxide
worked better than those without. However, the level of antibodies needed to
offer protection against H5N1 was currently unknown.
accompanying article, US experts Dr Suryaprakash Sambhara, from the Centres for
Disease Control and Prevention in Atlanta, Georgia, and Dr Gregory Poland, from
the Mayo Clinic College of Medicine in Rochester, Maryland, warned that a
vaccine powerful enough to hold back a pandemic was still
"We do not know if these vaccines are sufficient to protect
individuals in the event of an influenza pandemic," they wrote.
added that vaccine stockpiling options were also limited with the new vaccine
because two doses at 30 micrograms per dose were required. This restricted the
number of doses of vaccine it was currently possible for global manufacturers to
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