Have all the current strains of H5N1 become resistant to the Amantedines?
in a pandemic they probably will. When many people are treated with
Amantanes, and the virus walks through several of these hosts,
selection will create the resistance.
But, more realistically, assume that half of viruses are resistant
and half of people are treated with Amantanes.
After one virus-host-generation 2/3 are resistant, then 4/5,
8/9,16/17,… even when we discard that resistance can emerge
within a patient.
I believe I read that in at least one instance the resistance was already in the strain being examined. I brought this topic up up before and at that time there was still value to using amantadine. The problem is that for resistance to happen it only takes one of of three possible mutations for complete resistance. These mutations are highly volatile meaning that with any pressure they will surely happen. At least with tamiflu there is only one mutation that can cause resistance and its a much more stable part of the genome. Personally I do not put any stock in amantadine in a pandemic scenario. It might work in the immediate beginning but by the time you would likely get exposed to the pandemic it would be worthless. Find the other thread all this is discussed in detail.
This is a very rough delineation: Most of the strains in Asia including Indonesia are resistant. But the Qinghai strain and its offsprings in Europe and probably Africa are sensitive.
Webster and a few other scientists advocate combination therapy with oseltamivir and amantadine.
Yes - last i heard - months ago, H5N1 Qinghai was sensitive.
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