Was H1N1 leaked from a laboratory?

391 cases of H1N1 were confirmed in the UK yesterday bringing the total number of confirmed cases to 6929. In Argentina, the state of Buenos Aires has declared a health emergency, with schools closing for their winter breaks early – the city’s mayor has called for families not to “treat this as extra holidays for the kids” and more of a “time for the children to stay at home as much as possible”. Meanwhile Australia now has 4568 confirmed  cases (198 more yesterday) and 9 deaths.

Swine flu leak hits the headlines
The Independent and the Daily Mail are worried that swine flu might be a man-made disaster. The Mail says this:

The swine flu pandemic may have been caused by an accidental leak from a laboratory three decades ago, scientists have claimed.

I knew it! Tell me more…

An investigation into the genetic make-up of flu viruses claims the pandemic may not have occurred, had it not been for the accidental release of the same strain of influenza virus from a research lab in 1977.

Does that mean it’s been leaking for 32 years?

The study in the New England Journal of Medicine said: “Careful study of the genetic origin of the (1977) virus showed that it was closely related to a 1950 strain, but dissimilar to influenza ‘A’ (H1N1) strains from both 1947 and 1957.”

This finding suggested that the 1977 outbreak strain has been preserved since 1950. The re-emergence was probably an accidental release from a laboratory source.

Ok, but what’s that got to do with the current pandemic? I’ve read the article (and the one in the Independent several times now and can’t find the answer. I’d better move on though, or I’ll be accused of having a “lofty attitude” towards media health coverage.

The NEJM article on which this claim is based is well worth a read. It gives a comprehensive and fascinating history of Influenza A (H1N1) viruses. What they really say about the source of the current outbreak is less of a headline grabber, but just as interesting:

Although the immediate genetic event that led to the emergence of the new pandemic threat was a reassortment between two influenza A (H1N1) swine viruses, these two viruses were actually the products of at least four independent avian-to-mammalian cross-species transmissions, with at least four previous reassortments of gene segments among avian, human, and swine-adapted viruses.

If you prefer your theories more conspiratorial though, try this.

Tom Nolan is the clinical community editor of doc2doc, the BMJ’s professional networking community.