Can HPV infection be prevented?
The surest way to eliminate risk for genital HPV infection is to refrain from any genital contact with another individual.4
For those who are sexually active, a long-term, mutually monogamous relationship with an uninfected partner is the strategy most likely to prevent HPV infection.4 However, it is difficult to determine whether a partner who has been sexually active in the past is currently infected.
Research has shown that correct and consistent condom use can reduce the transmission of HPV between sexual partners.5 However, because areas not covered by a condom can be infected by the virus4, they are unlikely to provide complete protection against transmission of infection.
The Food and Drug Administration (FDA) has approved two vaccines to prevent HPV infection: Gardasil® and Cervarix®. Both vaccines are highly effective in preventing infections with HPV types 16 and 18, two high-risk HPVs that cause about 70% of cervical and anal cancers. Gardasil also prevents infection with HPV types 6 and 11, which cause 90% of genital warts.6
What are Gardasil and Cervarix?
The Gardasil vaccine is produced by Merck & Co., Inc. It is called a quadrivalent vaccine because it protects against four HPV types: 6, 11, 16, and 18. Gardasil is given through a series of three injections into muscle tissue over a 6-month period.
The FDA has approved Gardasil for use in females for the prevention of cervical cancer, and some vulvar and vaginal cancers, caused by HPV types 16 and 18, and for use in males and females for the prevention of anal cancer and precancerous anal lesions caused by HPV types 16 and 18. Gardasil is also approved for the prevention of genital warts caused by HPV types 6 and 11. The vaccine is approved for these uses in females and males ages 9 to 26.
The Cervarix vaccine is produced by GlaxoSmithKline (GSK). It is called a bivalent vaccine because it targets two HPV types: 16 and 18. This vaccine is also given in three doses over a 6-month period. The FDA has approved Cervarix for use in females ages 9 to 25 for the prevention of cervical cancer caused by HPV types 16 and 18.
Both Gardasil and Cervarix are based on technology developed in part by NCI scientists. NCI licensed the technology to two pharmaceutical companies—Merck and GSK—to develop HPV vaccines for widespread distribution.
Neither of these HPV vaccines has been proven to provide complete protection against persistent infection with other HPV types, although some initial results suggest that both vaccines might provide partial protection against a few additional HPV types that can cause cervical cancer.
Overall, about 30% of cervical cancers will not be prevented by these vaccines. Also, in the case of Gardasil, 10% of genital warts will not be prevented by the vaccine. Neither vaccine prevents other sexually transmitted diseases, nor do they treat HPV infection or cervical cancer.
Because the vaccines do not protect against all HPV infections that cause cervical cancer, it is important for vaccinated women to continue to undergo cervical cancer screening. There could be some future changes in recommendations for vaccinated women.