relenza: mode of action, page-32

Was recently at the American Thoracic Society meeting in San Diego at which there were some interesting presentations about avian influenza.

There have been some mouse studies on a reconstituted 1918 virus looking at gene and protien expression at certain times after infection.

Essentially the mice had makers of death pre ordained at 24 hours after infection.The presenter a very well respected influenza virologist suggested the time frames for the experiment were wrong, they should have looked at 2, 6,12 and 24 hours after infection.

The implications of this are significant, it is my view that the only strategy which will work on large numbers of patients is prophylaxis.

The case reports of response to treatment to date in the field I suspect have more to do with individual patient genetics/immune system than any fortuitous response to treatment.

The concerns of larger scale resistance to any agent used as prophylaxis in a population sense are real, however as an individual if you are told this infection has a one in two chance of killing you, but if you take this medication there is a one in ten chance the virus will be resistant to it.Im sure individuals will make there own minds up about the odds here.

One concern expressed by others is the local vs systemic question.There are several issued here, if the virus is transmitted by droplet infection then an agent given by inhaler may work well.However if the infection can be transmitted by faeco-oral transmission then an agent given by inhaler may not help.

Also if the mechanism of pathogenesis of the virus is by cytokine mediated storm then it is too much to expect that an agent delivered by inhalation will have much effect in the brain for example.

Similarly all the rhetoric about vaccination in pandemic situation is in my view futile as the science of vaccination for H5N1 viruses has many short commings. It is only weakly immunogenic, they all require a booster dose, and only generate a response over 21-42 days, they require culture in egg media which will be wonderfully effective if the chicken poputation is slaughtered en mass to control local outbreaks.

Ultimately I am reassured by the practice of the only scientist approved by the CDC to handle 1918 reconstituted virus of taking Tamiflu EVERY time he works in the Level 4 laboritory. I am also reassured that Tamiflu is currently available from some pharmacies on private script in Australia

I do not find it reassuring that the same scientist does not take Relenza, I do not find it reassuring that Relenza can not currently be obtained on script anywhere