Vaccine effective in preventing infection with oncogenic HPV

In a study conducted in North America and Brazil, a bivalent vaccine was effective in preventing infection with the two most common oncogenic human papillomavirus (HPV) types — HPV-16 and HPV-18. The researchers are hopeful that the vaccine will greatly reduce cervical cancer rates.

“Our findings indicate that the vaccine could contribute substantially to reducing worldwide rates of cervical cancer,” lead author Dr. Diane M. Harper, from Dartmouth Medical School in Lebanon, New Hampshire, said in a statement. Still, she adds that further studies with long-term follow-up are needed to verify that vaccination prevents this malignancy.The findings, which appear in the November 13th issue of The Lancet, are based on a study of 1113 women, between 15 and 25 years of age, who were randomized to receive three doses of the vaccine or placebo. The subjects were followed for up to 27 months for HPV infection with cervical cytology and testing of self-obtained cervicovaginal samples.Depending on the method of analysis and the type of infection, vaccine efficacy against HPV-16/18 ranged from 91.6% to 100%. The vaccine was slightly more effective against persistent infection compared with incident infection. The vaccine was 92.9% effective in protecting against cytologic abnormalities.Although no serious adverse events were linked to the vaccine, injection site symptoms, including pain, swelling, and redness, occurred significantly more often with the vaccine than with placebo. No significant difference in general symptoms or study withdrawal due to side effects was seen between the groups.Serologic testing revealed that treatment with the vaccine induced a robust anti-HPV-16/18 antibody response, the authors note.In a related editorial, Dr. Matti Lehtinen, from the National Public Health Institute in Helsinki, and Dr. Jorma Paavonen, from the University of Helsinki, comment that while the HPV vaccine shows great promise, the question of how vaccination should be implemented in national programs to “guarantee high coverage in adolescents before they become sexually active” remains to be answered.(Source: Lancet 2004;364:1731,1757-1765: Reuters Health: Oncolink: November 2004.)