| Fred Goodwin, CMA 2006-05-11, 1:26 am |
| Bird Flu Vaccine Looks Safe, Effective
http://www.healthday.com/view.cfm?id=532630
But it might not work against new strains of the virus, experts warn
By Amanda Gardner
HealthDay Reporter
WEDNESDAY, May 10 (HealthDay News) -- French researchers report that a
preliminary vaccine for the H5N1 strain of bird flu appears to be safe
and produced an immune response in healthy people.
It's not clear, however, that the vaccine would work in a real-life
situation, or if it would be effective against other strains of bird,
or avian, flu.
"The measures we used for the immune response are those used for the
seasonal vaccine and there's quite a lot of data that suggest that
these measures are likely to represent an effective vaccine," said Dr.
Melanie Saville, co-author of the study and influenza franchise leader
for clinical development at Sanofi Pasteur in Marcy l'Etoile, France.
"However, we don't know what level of antibody you need for protection
against H5N1," Saville said, "and we can't say whether the results we
see with the H5N1 vaccine would be similar for any other type of avian
strain."
Sanofi Pasteur sponsored the study, which appears online Thursday in
the journal The Lancet.
"This vaccine is more successful appearing than the last one that was
published but it's not an overwhelming immunological response and we
don't know if it works against cross strains," said Dr. Marc Siegel,
author of Bird Flu: Everything You Need to Know About the Next Pandemic
and clinical associate professor of medicine at New York University
School of Medicine. "This has potential but it's not an automatic
problem-solver."
The report came amid continued media and public frenzy over bird flu,
which was the subject of a grim ABC television network movie Fatal
Contact: Bird Flu in America, which aired Tuesday. The movie traces an
outbreak of the H5N1 bird flu virus that begins in a Hong Kong market
and mutates into a virus that's easily transmitted from human to human,
resulting in a worldwide pandemic.
The U.S. government went so far as to issue a viewer's guide to the
movie, stressing that the film was not a documentary and there is no
influenza pandemic in the world at this time.
In a bit of unintended irony, the movie's plotline contends that
researchers in France develop an effective vaccine -- but French
authorities refuse to give it to other countries.
The current H5N1 virus has generated more fear than normal because of
its virulence and ease of transmission among flocks of domesticated
birds.
So far, bird flu has killed more than 100 people in nine countries, the
lion's share in Vietnam, Indonesia and other parts of Asia. More than
200 million domestic fowl have been killed worldwide to help stem the
spread of the illness.
Human casualties remain largely confined to Asia and to people who have
had close and prolonged contact with infected birds, such as poultry
farm workers. But one-third of Americans polled said they personally
feared becoming infected with the bird flu.
That fear may be intensified with the looming threat that migrating
birds may soon bring the virus to American shores.
In any event, efforts to come up with an effective vaccine continue to
gather steam.
For the new trial, 300 healthy volunteers aged 18 to 40 received one of
six vaccine formulations at various doses and with or without an
adjuvant (a compound that increases the potency of other drugs).
Two doses of the vaccine (at either 30, 15 and 7.5 micrograms) were
delivered 21 days apart.
All the formulations appeared to be safe. The most effective
formulation was 30 micrograms with an adjuvant (66 percent of the
participants developed sufficient antibodies), the researchers said.
"We saw responses in all the groups, although the best response was
seen in 30 micrograms with the adjuvant," Saville reported.
For the smaller 7.5-microgram dose, more than 40 percent of volunteers
developed antibodies.
"This is interesting from a dose-sparing perspective because, in a
pandemic situation, you would want to have available as many doses as
you possibly can," Saville said.
The vaccine was produced under an accelerated manufacturing process
designed to make vaccine available as quickly as possible after a
pandemic outbreak. "With everything going full speed, we would
anticipate that it would take approximately three months to actually
produce the vaccine according to the necessary standards," Saville
said. "It's not business as usual."
U.S. Health and Human Services Secretary Mike Leavitt was recently
quoted as saying that, with current capabilities, it would take at
least six months to create a vaccine.
In an accompanying comment piece in the journal, Suryaprakash Sambhara,
scientist from the U.S. Centers for Disease Control and Prevention,
warned that it's unclear if the vaccine would work in the event of a
real pandemic, and also pointed out that the vaccine response level was
not optimal.
A growing chorus of experts, including Sambhara, are advocating that
new methods be tested for production of an avian flu vaccine.
Siegel said: "It underlines the need for more research on using updated
techniques. You can't see an emerging virus and start using this
technique. It would take six to nine months. This underlines the need
for more money and more research done on other methods."
More information
For more on bird flu, head to the U.S. Centers for Disease Control and
Prevention.
SOURCES: Melanie Saville, M.D., influenza franchise leader for clinical
development, Sanofi Pasteur, Marcy l'Etoile, France; Marc Siegel, M.D.,
author, Bird Flu: Everything You Need to Know About the Next Pandemic,
and clinical associate professor of medicine, New York University
School of Medicine, New York City; May 10, 2006, online edition, The
Lancet
Last Updated: May 10, 2006
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