Certain strains of the virus responsible for causing Genital Warts - human papillomavirus or HPV - are also likely to trigger Cervical cancer. Now comes news that a vaccine designed to combat four of these strains can dramatically reduce persistent infection and the risk of developing warts and cancer.

The findings are similar to results seen when a two-hit vaccine was tested in North America and Brazil last year. However, in that study, the vaccine targeted only HPV-16 and HPV-18, the main cancer-causing types, whereas the new four-strain ‘quadrivalent’ vaccine targets these types as well as HPV-6 and HPV-11, the ones most often linked to genital warts.

The study involved 552 young women who were not pregnant, had no history of abnormal Pap smears, and had had no more than four sexual partners. Women with previous HPV infection were not excluded from the study.

The women were given three shots of the quadrivalent vaccine or placebo injections over a period of six months. They were then followed for 36 months with regular gynecologic exams, cervical testing for HPV, and Pap smear tests.

Compared with placebo injections, the vaccine led to 90 percent fewer cases of persistent infection or disease due to HPV types 6, 11, 16, or 18, lead study author Dr. Luisa L. Villa, from the Ludwig Institute for Cancer Research in Sao Paulo, Brazil, and colleagues report in the medical journal Lancet Oncology.

The vaccine was 89 percent effective in preventing infection with the four HPV types, and 100 percent effective in preventing the diseases associated with these types, the investigators point out.

As well as preventing clinical disease caused by common HPV types, the vaccine was generally well tolerated, the authors state. “Large-scale studies are under way.”

The study was funded by Merck Research Laboratories, which is developing the vaccine.

SOURCE: Lancet Oncology, online April 7, 2005.