Human papillomavirus (HPV)

Human papillomavirus (HPV) is the most common sexually transmitted infections in the United States. Sexually transmitted HPVs, common in adults and sexually active adolescents, more often than not are harmless and come and go without causing any symptoms. However, there is a subset of 19 high-risk HPV types that can lead to the development of cervical cancer and genital warts. Whereas genital warts can cause discomfort and psychosocial trauma, cervical cancer, if not detected in the early stages, can be deadly. Therefore, a vaccine that would protect against these diseases, especially cervical cancer, would be beneficial indeed.

In 2006, the FDA approved the first preventive HPV vaccine marketed by Merck and Co. under the trade name Gardasil. Gardasil, a recombinant vaccine (contains no live virus), is a preventive rather than a therapeutic vaccine and is recommended for women who are between 9 and 25 years old who do not have HPV.

The vaccine will not protect a woman it she has been infected with HPV types prior to the vaccination, indicating the importance of getting immunized before potential exposure to the virus (before initiation of sexual activity). A series of three shots over a six-month period was shown to offer 100 percent protection against the development of cervical precancers and genital warts caused by the HPV types in the vaccine. The protective effects of the vaccine are expected to last a minimum of four and a half years after the initial vaccination.

The vaccine represents a significant advance in the protection of women's health.
There are, however, a couple of drawbacks to the vaccine that have sparked debate.

First, the vaccine is expensive. Second, the vaccine offers no protection against other specific types of HPV that also can cause cervical cancer (there are more than 120 known HPV types, and 27 are known to be transmitted through sexual contact). The vaccine targets two of the most common high-risk HPVs, type 6 and 18, which cause 70 percent of all cervical cancers, and HPV types 6 and 11, which cause about 90 percent of all cases of genital warts. Third, it is unknown whether the vaccine's protection against HPV-16, in particular, is long lasting. Fourth, because the vaccine works only against specific kinds of HPV, regular Pap tests should still be performed. And, fifth, the vaccine is targeted only to females, leaving males to serve as an asymptomatic reservoir for the virus.

Perhaps the most contentious issue of HPV vaccination is the recommendation to vaccinate young girls. Social conservative religious groups have publicly opposed the concept of making HPV vaccination mandatory for preadolescent girls because they fear that this might send a subtle message that sexual intercourse is acceptable, thus detracting from their abstinence-based position. Other critics question mandating the vaccine for young girls.[42, 43] They argue that the vaccine does not address a public health threat as serious as polio, measles, or other childhood illnesses and contend that the vaccine is too new for its long-term safety and effectiveness to be known. Adverse events related to Gardasil use have been reported, raising public concern, but the CDC and FDA recently determined that the serious events were not due to vaccination and that Gardasil was safe.[44, 45]