Swine flu science update: 5 October 2009
Genetic similarities between the swine flu virus — influenza A(H1N1) — and other circulating viruses may explain the unexpected effectiveness of a single dose pandemic vaccine.
Scientists testing A(H1N1) vaccines have been mystified to find people developing protective antibodies after just one shot rather than the expected two for a new virus, New Scientist reported last month (17 September).
But this apparent partial immunity may be the result of A(H1N1) sharing some gene segments with a recently circulating H1N1 virus and a currently circulating H3N1 virus, according to a report in The New England Journal of Medicine (10 September).
The WHO expects to send the first batches of donated vaccine to developing countries next month, said Marie-Paule Kieny, director of the WHO Initiative for Vaccine Research, at a press conference last month (24 September). Two pharmaceutical companies have agreed to donate 150 million doses to low-income countries and ten rich nations have pledged ten per cent of their stocks.
The WHO puts worldwide production capacity for pandemic vaccines at three billion doses per year, at best.
A WHO funding request for US$1.5 billion to prevent the flu pandemic spiralling into a global disaster is not being met with enthusiasm by some scientists and health policymakers, the Associated Press reported (24 September).
The money is being requested for vaccination programmes, antivirals and health system support in developing countries. But critics say the WHO is using A(H1N1) as a convenient fund-raiser.
"WHO is peddling an alarmist, unscientific agenda to raise funds," said Philip Stevens, health programme director at the UK-based International Policy Network.
The WHO has recommended that seasonal H1N1 flu be dropped from the 2010 Southern hemisphere vaccine programme as it has caused few outbreaks since A(H1N1) emerged in April, according to ScienceInsider (23 September).
Whether or not the Southern Hemisphere will need separate vaccines for next winter's seasonal and pandemic influenzas will be debated later this month by the WHO's Strategic Advisory Group of Experts.
An international collaboration of eminent scientists has called for improved surveillance of influenza A(H1N1) in developing countries to better understand how the virus is circulating globally and affecting rates of illness and death.
Writing in Science (2 October), the scientists said extra surveillance would address the knowledge gaps about the virus, including the role of antibodies, immune cells and immune memory. They also proposed that influenza vaccines should be added to vaccination programmes in tropical countries.
Research to be published soon in the Journal of the American Medical Association finds surgical facemasks almost as effective as disposable respirators in preventing flu in healthworkers.
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In a study of 450 Canadian nurses caring for patients with respiratory disease, influenza infection occurred in 24 per cent of carers wearing regular masks compared with 23 per cent wearing N-95 respirators, which filter out small particles.
Up to half of unexpected flu deaths happen to patients with pre-existing heart disease, according to research published in The Lancet Infectious Diseases (October). The researchers reviewed 39 studies of heart patients and found consistent associations between influenza and heart attacks. They call for everyone with heart disease to be vaccinated.