Study: Gardasil does not cause autoimmune disease

There have been anecdotal reports that Gardasil, Merck's ($MRK) human papillomavirus vaccine, causes autoimmune disease. A study of almost 200,000 women over two years may finally scotch this rumor, or at least offer some scientific data to balance out the argument.

The two-year study, carried out by Kaiser Permanente researchers, tracked 189,629 Californian women and girls between 9 and 26 years of age with no sign of autoimmune disease for 6 months after they received each dose of Gardasil, and compared them with a control group that had never received the vaccine. The results showed no increase in 16 autoimmune diseases, including lupus, rheumatoid arthritis, Type 1 diabetes and multiple sclerosis, and no autoimmune safety concerns.

"These findings offer some assurance that among a large and generalizable female population, no safety signal for autoimmune conditions was found following HPV4 vaccination in routine clinical use," said study lead author Chun Chao, a research scientist at Kaiser Permanente.

Gardasil is designed to protect against genital warts, the most common sexually transmitted infection in the U.S., as well as cervical cancer, which can arise after HPV infection. Clinical trials can be small and focused on a selected population. Although Merck funded this study, it has been published in a peer-reviewed journal, the Journal of Internal Medicine. Because of this, and because the group of women was large and included a mixture of ethnic backgrounds and ages, it may offer more reassurance to parents deciding whether to allow their daughters to receive the vaccine, which will offer them long-term protection against HPV and cervical cancer.

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