U.S. experts concerned about effectiveness of Tamiflu

LOS ANGELES, July 8 (Xinhua) -- Amid reports of Tamiflu-resistant H1N1 cases, health officials are concerned about how quickly a new strain of the virus resistant to the drug Tamiflu will spread, or how dangerous it might become.

A man leaves a school, attended by children  from the five new confirmed cases of  influenza A (H1N1), after collecting a box  of Tamiflu in south London May 4, 2009.  (Xinhua/Reuters File Photo)

Although, isolated cases of the A/H1N1 virus, seem mild for now, but future remains uncertain, the Health Day News reported on Wednesday

So far, three people have been stricken in recent weeks by a resistant strain of the new H1N1 flu virus -- one in the United States, one in Denmark and one in Japan, according to earlier press reports.

In all three cases, the illnesses were mild and all of the patients recovered.

More widespread resistance could come from one of two scenarios, John J. Treanor, professor of medicine and of microbiology and immunology at the University of Rochester Medical Center in New York, said in remarks published by Health Day News.

The first would be if the virus develops mutations in people who are being treated with Tamiflu and then spreads to others, Treanor said.

The second would involve a random genetic reassortment, in which the new swine flu and the seasonal flu exchange genes, he said.

"The current seasonal viruses are resistant to Tamiflu," Treanor noted. "We could see a get-together resulting in a hybrid which ... potentially could be able to infect people more easily."

"This is not unexpected, but it's very unpredictable whether this will end up spreading," said Treanor.

"There is certainly a potential for the novel H1N1 viruses to develop resistance to oseltamivir (Tamiflu) and for those resistant viruses to become widespread," he added.