NEW YORK (Reuters Health) - The use of a quadrivalent vaccine can dramatically reduce persistent infection, cervical cancer and genital warts associated with human papillomavirus (HPV), according to a report in the April 7th online issue of The Lancet Oncology.
The new findings are similar to those seen when a bivalent vaccine was tested in North America and Brazil (see Reuters Health report November 11, 2004). However, in that study, the vaccine only targeted HPV-16 and HPV-18, the main oncogenic types, whereas the 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 a lifetime history of no more than four sexual partners. Women with previous HPV infection were not excluded from the study.
The subjects were randomized to receive the quadrivalent vaccine or placebo at day 1, month 2, and month 6. The subjects were then followed for 36 months with regular gynecologic exams, cervical testing for HPV DNA, and Pap testing.
Compared with placebo, use of the quadrivalent vaccine was associated with a 90% drop in the combined incidence of persistent infection or disease with HPV-6, -11, -16, or -18, lead author Dr. Luisa L. Villa, from the Ludwig Institute for Cancer Research in Sao Paulo, Brazil, and colleagues note.
The vaccine was 89% effective in preventing infection with the four HPV types, but 100% effective in preventing the diseases associated with these types, the investigators point out.
“This study has shown that a candidate HPV-6, -11, -16, and -18 vaccine was generally well tolerated, induced high titres of serum antibodies to HPV types, and effectively prevented acquisition of infection and clinical disease caused by common HPV types,” the authors state. “Large-scale studies are under way.”
The study was funded by Merck Research Laboratories, which is developing the vaccine.
Source: Lancet Oncol 2005. [ Google search on this article ]
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