The first sign of potential resistance to Tamiflu has emerged in Denmark. A patient with influenza A(H1N1) appeared to show resistance to the antiviral drug, which has been used to prevent the virus spreading in communities. But David Reddy — executive director of Roche Holding AG, who confirmed the case — says that there are no other signs of a Tamiflu-resistant strain of influenza A(H1N1) circulating in the community.
Meanwhile, a small US pharmaceutical company says it has developed a vaccine against swine flu, using insect cell technology, the Agence France-Presse (AFP) said.
Dan Adams, CEO of the Connecticut-based Protein Sciences Corporation, said his company had produced 100 000 doses of the vaccine on a US $35 million contract from the US Department of Health and Human Services.
AFP said Protein Sciences made the flu vaccine by infecting caterpillar cells with a baculovirus carrying the gene for hemagluttinin, a molecule that sticks out of the surface of the influenza virus. Insect cell technology does not need a "seed strain", which is used in the normal production of vaccines.
Elsewhere, French drug maker Sanofi-Aventis announced that it has begun production of a vaccine for swine flu at its facilities in the United States and France. The vaccine has been developed using conventional egg-based vaccine technology, the company said.
In India, scientists have begun to issue warnings about the widely held fears that a second, more deadly wave of the disease may occur later this year.
In an interview with the Times of India Naresh Gupta — a senior doctor at Maulana Azad Medical College in New Delhi — pointed out that the 1918 Spanish influenza pandemic began with a mild wave in March followed by a more lethal second wave later in the year, going on to kill 40 million people.
Gupta's comments were reinforced by Vineet Chawdhry — joint secretary in the Ministry of Health and Family Welfare — who told the newspaper that a second wave of the flu would be "more potent".
Nature China reports that a researcher from the University of Hong Kong, working with British scientists, has found further evidence that the virus developed over a number of years. The researchers concluded that the virus originated from several viruses in pigs and that it contained "genetic elements of avian, human and classical swine origins".
Meanwhile, researchers studying who is most at risk from severe illness as a result of swine flu infection say in the New England Journal of Medicine that prevention efforts should be focused on younger people, if resources or vaccines are limited. They have produced evidence showing that those exposed to strains of H1N1 that were circulating around the world before 1957 seem to have some protection against severe illness.