Bird Flu Vaccine Protects Half The People Who Take It

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Main Category: Bird Flu / Avian Flu
Also Included In: Immune System / Vaccines
Article Date: 30 Mar 2006 - 17:00 PDT

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According to researchers, a new experimental bird flu (avian flu) vaccine protects 54% of people who get two shots at a very high dose (90 micrograms). This dose is twelve times higher than that needed for protection from normal human flu.

You can read about this research in the New England Journal of Medicine (NEJM).

451 volunteers took part in this trial.

70% of those who got the shot had some kind of immune response, however, it was not possible to know how protective this response might be, said the researchers.

According to Dr. J Treanor, University of Rochester, New York, even at such a high dose, the vaccine seems to be completely safe for humans. He also added that as nearly all humans have not been exposed to H5N1 at all, developing an immune response takes time.

Whether or not a third dose may up the immune response of more participants remains to be seen. The scientists say they plan to administer a third dose. They also said that by adding such chemicals as alum or MF59, it may be possible to lower the dose.

As there are now two types of H5N1 virus strains, it is not known whether this vaccine offers protection from both.

The vaccine is made by Sanofi-Aventis and was developed from a H5N1 virus strain obtained in Vietnam two years ago.

For a human to become ill as a result of H5N1 infection, the virus has to make its way deep into the lungs. This is why humans cannot catch bird flu easily and cannot easily transmit it to other humans. An infected person who coughs or sneezes expels hardly any of the viruses (because they are too deep inside the lungs). If the virus mutates, so that it can easily be transmitted from human-to-human, it will need to attack the upper parts of the lungs. If it manages to do this, it will be much easier to treat.

Written by: Christian Nordqvist
Editor: Medical News Today
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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