Gardasil

Gardasil is a widely available vaccine against certain types of the human papillomavirus (HPV), a virus that infects skin and mucous membranes in humans. Gardasil was developed by Merck, and is effective against four types of HPV: types 6 and 11, which are responsible for 90 percent of cases of genital warts in females, and types 16 and 18, which are responsible for approximately 70 percent of cervical cancer cases.

The vaccine consists of virus-like particles very similar to HPV, that, when injected, cause an immune response that generates antibodies against HPV. When administered appropriately (three doses within a six-month period) Gardasil is nearly 100 percent effective in preventing the development of precancerous cervical cells. Gardasil is effective for at least four years, and some preliminary studies suggest its protective effects probably last much longer. Since it only prevents (rather than treats) HPV infection, it is most effective if given before becoming sexually active, typically between the ages of 11 and 25 years. [Page 597]However, when Gardasil is given to women already infected with one HPV type, the vaccine still protects them from the other types.

It is currently approved for use in females and has recently been approved for males aged 9 to 26. The four types of HPV targeted by Gardasil are associated with other genital cancers in both men and women, including vulvar, vaginal, anal, and penile cancer. In rare cases, HPV is associated with head, neck, throat, and lung cancers. Although uncommon, HPV can be passed from mother to newborn, particularly if she has an outbreak of genital warts at the time of delivery.

Despite the fact that Gardasil is not advertised to do so, it clearly has the potential to reduce rates of these other diseases. Both the U.S. Food and Drug Administration (FDA) and the U.S. Centers for Disease Control and Prevention (CDC) consider Gardasil to be safe, and it has been approved for use in more than 112 countries. Side effects from the vaccine are considered minor, and include headache, fatigue, and soreness around the injection area. Because the vaccine does not contain a complete virus, only virus-like particles, there is no chance of the virus reproducing in the body and causing disease.

Merck and some legislators have suggested making Gardasil mandatory for school attendance. However, some groups are concerned that vaccination with Gardasil will stop women from getting Pap smears, and that it might give young girls a false sense of security regarding safer sex practices. Vaccination against HPV is a cost-effective healthcare strategy. In addition to reducing the incidence of cervical cancer by 70 percent, fewer HPV infections means fewer biopsies following uncertain Pap test results, and a reduced need for long-term management of genital warts. However, achieving mass vaccination may be difficult since the vaccine currently costs $360 ($120/dose plus any additional physician fees) and is not covered by all insurance companies.