relenza: mode of action

For those interested in how Relenza works, this Tamiflu web site provides some good simple information.

http://www.pharmasquare.org/flash/Tamiflu.html

The only difference with Bird Flu from the Tamiflu presentation is that the H5N1 virus cannot bind to cells high in the respiratory tract. H5N1 binds to specific receptors on cells that are only found deep in the lung. Therefore, it is difficult to catch the virus unless you have significant exposure and some of the virus makes it deep into the lung.

Nasal exposure to H5N1 is unlikely to make you ill. There have been reports of people being found to have H5N1 antibodies (appear to have contracted the virus) but have not been ill. It is thought that the virus may have infected a lone, or small number, of cells high in the respiratory tract but since there were few other nearby cells capable of becoming infected, the immune system defeated the virus with few if any symptoms.

The pandemic concern springs from the fact that viruses can mutate, or combine with other human flu viruses, and become capable of binding to receptors higher in the respiratory tract. Cases of human to human transmission do not necessarily mean that the virus has mutated. Some human to human transmission should not be unexpected if the infected humans have very close contact.


Cheers

Mick