Smallpox clue to AIDS battle

Tuesday May 18th, 2010

The world needs to learn the lesson from smallpox eradication to combat the threats to 21st century health, a global gathering was told yesterday.

Smallpox was declared ended 30 years ago after a concerted international campaign.

But one new analysis today says the success may have had an unintended consequence - opening the way for the HIV virus.

The smallpox vaccine was the first ever discovered - by Edward Jenner.

Scientists in Virginia, USA, say the smallpox vaccine seems to protect against HIV - and may have held back the outbreak of the virus for decades.

If the theory is correct, it could also mean that the smallpox vaccine could be adapted to protect against HIV.

Researchers conducted laboratory studies of white blood cells taken from people vaccinated against smallpox and found that HIV spread much less fast in these cells than in samples from unvaccinated people.

The findings are reported in the journal BMC Immunology.

Researcher Dr Raymond Weinstein, of the George Mason University, Manassas, Virginia, said: "While these results are very interesting and hopefully may lead to a new weapon against the HIV pandemic, they are very preliminary and it is far too soon to recommend the general use of vaccinia immunisation for fighting HIV.

He added: "There have been several proposed explanations for the rapid spread of HIV in Africa, including wars, the re-use of unsterilised needles and the contamination of early batches of polio vaccine. However, all of these have been either disproved or do not sufficiently explain the behaviour of the HIV pandemic.

"Our finding that prior immunisation with vaccinia virus may provide an individual with some degree of protection to subsequent HIV infection suggests that the withdrawal of such vaccination may be a partial explanation."

Speaking at the World Health Assembly in Geneva, Switzerland, yesterday, World Health Organisation director general Dr Margaret Chan said: "Smallpox eradication was a single-disease initiative. That killing, blinding, disfiguring disease never had a cure. The cornerstone of the campaign was prevention at a time when most health systems around the world were designed to deliver curative care.

"An initiative that broke every single chain of virus transmission in every corner of the world was the ultimate example of universal coverage. This tells us what collective action for a common cause can achieve."

Significantly Reduced CCR5-tropic HIV-1 Replication in vitro in Cells from Subjects Previously Immunized with Vaccinia Virus. Raymond S Weinstein, Michael M Weinstein, Kenneth Alibek, Michael I Bukrinsky and Brichacek Beda: BMC Immunology (in press)

Tags: Flu & Viruses | North America | World Health

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