Swine Flu Pandemic Update: Tamiflu-Resistant H1N1 Strain Surfaces in Denmark

The New York Times reported today that a case of Tamiflu-resistant H1N1 swine flu has surfaced in Denmark. The Danish patient in which Tamiflu-resistance developed ironically did not have an active case of H1N1 swine flu but was receiving prophylactic drug treatment after a close associate was diagnosed with H1N1 swine flu. He developed a drug resistant strain during treatment but fully recovered.

Tamiflu resistance is not uncommon and has already occurred with seasonal flu. Health authorities were anticipating the possibility that a Tamiflu resistant strain of H1N1 swine flu would develop. The strain identified in Denmark is weak, according to Danish health authorities, and unlikely to spread among larger populations. Tamiflu resistance also developed with H1N1 seasonal flu last year, but unlike the swine flu strain, the seasonal flu strain resistant to Tamiflu is widespread.

Tamiflu and Relenza are the only antivirals known to be effective against H1N1 swine flu.

Worldwide, the World Health Organization (WHO) reports that 311 people have died of confirmed cases of H1N1 swine flu while more than 70,000 have contracted the virus. Actual death tolls may be higher as some countries do not have the capacity for testing outbreak victims to confirm the cause of death.

On June 11, WHO raised the pandemic alert level to 6, indicating a full scale pandemic. WHO noted that while the majority of H1N1 swine flu patients have suffered moderate symptoms and fully recovered, one third to one half of the severe and fatal infections are occurring in previously health young people. H1N1 swine flu had been identified in 70 countries worldwide as of the date a full scale pandemic was declared.

The Wall Street Journal reported that a spokesman for Roche Holding AG, maker of Tamiflu asserted in the wake of this news from Denmark that Tamiflu remains effective in fighting H1N1 swine flu and called the development of a drug resistant strain unsurprising from a scientific point of view.

Of greater concern to scientists is widespread drug resistance developing if H1N1 swine flu combines with seasonal viruses. Health experts are watching the southern hemisphere, where winter is underway, closely for signs of new viral combinations.

Sources: http://www.nytimes.com/2009/06/30/health/30glob.html?hpw; http://news.bbc.co.uk/2/hi/health/8124987.stm; http://www.who.int/mediacentre/news/statements/2009/h1n1_pandemic_phase6_20090611/en/index.html; http://www.nytimes.com/2009/06/30/health/30glob.html; http://online.wsj.com/article/BT-CO-20090629-710385.html.