Swine flu science update: 24 November 2009
The WHO is scheduled to start shipping swine flu — influenza A(H1N1) — vaccine to developing countries at this end of this month [44kB], the director of its Initiative for Vaccine Research has announced.
Marie-Paule Kieny told a press briefing last week (19 November) that the WHO hopes to send vaccine to all 95 eligible countries in the next three months. The first delivery will go to 35 "or slightly more" countries.
Novartis announced last week (17 November) that half a dose of its A(H1N1) vaccine is enough to provide immunity to the virus. Reuters reported that this could quadruple the drug company's vaccine supply. An adjuvant — an additive used to boost the body's immune response — was also found to be well tolerated.
The common cold may prevent A(H1N1) infection by activating the body's antiviral defence system, researchers have told New Scientist (12 November).
Reports from several countries show that a rise in the number of infections with the cold-causing rhinovirus — which often happens when schools open — matches a fall in the incidence of influenza A(H1N1). But this effect is not strong enough to fight off A(H1N1) if someone is repeatedly exposed.
Catching seasonal flu could also confer a degree of immunity against influenza A(H1N1) [0.98kB], possibly resulting in a less severe infection, say scientists from the La Jolla Institute for Allergy and Immunology in the United States.
The researchers found that the immune system recognises the parts of A(H1N1) shared with seasonal flu — but the A(H1N1) vaccine is still needed to protect against unique markers on the A(H1N1) surface. The results were published last week (17 November) in the Proceedings of the National Academy of Sciences.
People born before 1950 are more likely to have pre-existing immunity to A(H1N1) than those born after 1980, a study published in the New England Journal of Medicine (12 November) has shown.
Researchers found that 34 per cent of samples from people born before 1950 had immunity, compared with four per cent from people born after 1980. The study also reported that seasonal flu vaccines induced little or no immunity to A(H1N1) in any age group.
The WHO has stated that the influenza A(H1N1) vaccine was not to blame for 41 deaths associated with the jab, Reuters reported last week (19 November).
Marie-Paule Kieny told a press briefing that although some investigations were still being carried out, results already obtained ruled the vaccine out as a cause of the deaths. She also voiced concern that some members of high-risk groups, such as pregnant women, are avoiding the vaccine for fear of side effects.
Chinese doctor Zhong Nanshan has been quoted in the Southern Metropolis Daily, a newspaper in China's Guangdong province, as saying he suspects the country has had more A(H1N1) deaths than have been officially reported.
The newspaper quoted Zhong as saying: "Some areas have not been testing deaths from severe [pneumonia] and treating them as cases of ordinary pneumonia without a question".
Reuters said (18 November) that Zhong was respected in China for his candour and work in fighting severe acute respiratory syndrome (SARS) in 2003.
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