Tamiflu Resistant Pandemic H1N1 in Denmark Raises Concerns
Recombinomics Commentary 16:11
June 29, 2009
The first case in the world of resistance to influenza drug Tamiflu in people with influenza H1N1 has been found in Denmark. The person is now healthy, and there is no further evidence of infection with resistant virus, according to Statens Serum Institut.
We do not expect that the longer exist, says Nils Strandberg Pedersen, Managing Director, Statens Serum Institut, and refers to the mutated form of H1N1. The infected Dane had been in close contact with another infected person, and was therefore prevented treatment with Tamiflu.
Yet the person had flu symptoms and are instead treated with another type of flu drugs, Relenza.
The above translation describes the detection of oseltamivir (Tamiflu) resistance in a patient infected with pandemic H1N1. Although details of this breaking news are sketchy, it sounds like resistance (likely H274Y) develop during prophylactic treatment, much like the first reported case of resistance in H5N1 in Vietnam in 2005.
In Vietnam, the sister of an infected patient was given a prophylactic dose of oseltamivir and developed symptoms. Resistance (H274Y and N294S) was found in isolates from the contact. However, she recovered after the treatment dose was increased, and the resistant H5N1 did not spread.
However H274Y was subsequently found in seasonal H1N1, which was evolutionarily fit and did spread worldwide.
The latest results with pandemic H1N1 do not address fitness if the first patient did not have resistant H1N1, and the ability of a pandemic H1N1 with H274Y or N294S is unclear. However, the description appears to rule out acquisition of resistance via reassortment with seasonal flu with H1N1.
More detail on the above case, as well as the sequence of the resistant H1N1, as well as H1N1 from the contact, would be useful.