By Ned Stafford

FRANKFURT (Reuters Health) Oct 15 - Adults who as children were vaccinated against smallpox and/or tuberculosis are at less risk for melanoma than those who were not vaccinated, according to findings from study conducted by a team of researchers assembled by the Brussels-based European Organisation for the Research and Treatment of Cancer.

The leader of the study, Dr. Klaus Koelmel, of the University Hospital in Goettingen, Germany, told Reuters Health that 11 institutions in 6 European countries and in Israel participated in the study. In a population-based case-control design, 603 people with melanoma and 627 without melanoma were matched with respect to sex, age, and ethnic origin.

As reported in the latest issue of The Journal of Investigative Dermatology, the odds ratio for melanoma associated with a history of vaccinia and bacille Calmette-Guerin vaccination was 0.44 compared with no history of either vaccination.

The study results showed that adults under 50 years old who as children had been vaccinated against either tuberculosis or smallpox had about a 25% lower risk of melanoma than those not vaccinated, Dr. Koelmel said. In the under-50 group, no additional effect was seen for those who had been given both vaccinations as children.

For people older than 50 with only one of the vaccinations, the protection against melanoma, was smaller than with the under 50-year-olds, in line with the notion that the effectiveness of smallpox vaccination decreases with age, he said. However, unlike the under-50 group, those in the older age group who had both vaccinations as children had increased protection against melanoma, he said.

Dr. Koelmel said that the protective effect probably stems from an "unspecified immunological mechanism," which probably "extends to other cancers." He said that the findings of the study are plausible, but that future studies are necessary to confirm them.

J Invest Dermatol 2002:119:570-575.

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