Old flu vaccine may protect against new virus
Wednesday October 7th, 2009
People
who were vaccinated against ordinary flu last winter may have been enjoying
protection against the new swine flu virus, researchers report today.
The findings come from Mexico where the new H1N1 virus originated.
Researchers said their findings need to be treated with caution - but they challenge the idea that H1N1 is so different from ordinary flu that existing vaccines were useless against it.
And they may provide an extra reason why elderly people have proved less susceptible to the new swine flu than others - as the elderly are most likely to be offered flu vaccine.
The Mexico City study, reported by the British Medical Journal, involved an analysis of just 240 patients.
Doctors compared swine flu victims with other patients who were in hospital for other diseases.
They found those without swine flu were by far the most likely to have undergone flu vaccination the previous winter. However many of these people suffered from chronic conditions, such as asthma and diabetes - which would have meant doctors giving them priority for flu vaccination.
The researchers say they used statistical techniques to allow for this bias and that there was still a significant link between being unvaccinated and contracting swine flu.
The study found that eight of the 60 who were treated for swine flu had received flu vaccination - compared with 53 of the 180 other patients. 18 of the swine flu patients died.
Researcher Dr Jose Luis Valdespino writes that the "results should be considered cautiously - and in no way indicate that seasonal vaccine should replace vaccination against pandemic influenza A/H1N1 2009."
Writing in the same journal, Dr Menno de Jong, of the University of Amsterdam, Netherlands, says the findings do not undermine the drive to introduce vaccines designed specifically for swine flu.
He warns: "Vaccinated people may be protected only after the peak of the pandemic has passed. To protect against seasonal and pandemic strains, vaccines and vaccine production need to improve."
British Medical Journal October 7 2009
Tags: Europe | Flu & Viruses | North America | Traveller Health | World Health
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