Swine flu science update: 22 September 2009
A group of rich nations has pledged to donate ten per cent of its swine flu — influenza A(H1N1) — vaccine supplies to poor countries.
The move follows pressure from WHO director-general Margaret Chan over concerns that developing countries would have little or no access to vaccines.
Australia, Brazil, France, Italy, New Zealand, Norway, Switzerland, the United Kingdom and the United States have pledged either vaccine or a cash equivalent, The Financial Times reported last week (18 September). The aim is to provide 300 million vaccines doses.
A genetic mutation could explain why some people suffer severely or even die from swine flu while others experience only mild symptoms.
The early results of a multi-hospital study of severe A(H1N1) cases suggest severity is linked to a genetic variation in the immune system, New Scientist reported this month (September 9). This could explain why some ethnic groups are more affected by flu.
Trial coordinator, Anand Kumar, an intensive-care expert at Canada's University of Manitoba, told a meeting in Winnipeg last week that extreme A(H1N1) cases were "the sickest people I've ever seen".
Rewiring the 'packaging signals' in the genetic material of the influenza virus can stop it recombining with other influenza strains to make a new, stronger virus, researchers have found.
Swapping the genes that control the way influenza gene segments are packaged prevents viruses exchanging genetic material, say Qinshan Gao and Peter Palese, from the Mount Sinai School of Medicine in New York, writing in the Proceedings of the National Academy of Sciences this month (8 September).
Researchers at Nagasaki University in Japan have found that a single dose of an intravenous influenza drug is as effective as a course of Tamiflu capsules taken over five days.
Results from a trial of the experimental drug, peramivir, were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco this month (12–15 September).
The Associated Press reports that peramivir cleared flu symptoms in 78 hours compared with 82 hours for Tamiflu. Adverse drug reactions were also less common with peramivir.
The A(H1N1) virus was circulating undetected in pigs for almost a decade and had been affecting humans for several months before it was first diagnosed, according to virus specialist Michael Worobey of the University of Arizona. He told a meeting of flu experts last week (15 September) that the virus is now mutating 1.5 times faster than it was in pigs.
The goal of creating a single repository for sharing data on influenza is in jeopardy after a dispute between the co-founders of the EpiFlu database, the Global Initiative on Sharing Avian Influenza Data (GISAID) and the Swiss Institute of Bioinformatics (SIB).
Scientific American reported last week (14 September) that GISAID has now launched its own version of EpiFlu, after SIB withdrew access to the database from the GISAID website last July.
GISAID's database contains information from EpiFlu as well as new data contributed by organisations such as the UN Food and Agriculture Organization.