The Food and Drug Administration approved Gardasil vaccine, manufactured by Merck and Co. in June of 2006 for the prevention of cervical cancer and genital warts (See Reference 2). The Centers for Disease Control and Prevention recommended that girls and women between the ages of 11 and 26 receive a 3-dose vaccination (See Reference 1).
Cervical Cancer
The CDC reports that every year nearly 12,000 women are diagnosed with cervical cancer and approximately 4,000 die from this cancer in the United States (See Reference 1). The CDC estimates that cervical cancer causes the deaths of 233,000 women worldwide every year. The Pap smear is a screening tool used to detect abnormal cell growth in the cervix and its use has significantly decreased the mortality associated with cervical cancer. Gardasil vaccination is not a replacement for Pap smear screening.
Human Papilloma Virus
Human papilloma virus, or HPV, infection is the most common sexually transmitted infection in men and women. There are more than 40 different types of sexually transmitted HPVs. In most infections, the immune system eradicates the virus and the infection disappears. Persistent infections may cause changes in normal cell growth in the cervix that can lead to the development of genital warts and cervical cancer. The CDC reported that greater than 70 percent of cervical cancers are caused by infection with HPV types 16 and 18. HPV infection can also cause vulvar, penile, vaginal, anal and some head and neck cancers.
Vaccine
Gardasil was the first vaccine approved in the United States to prevent cervical cancer. The Gardasil vaccine contains proteins that resemble those on certain HPV types. These viral like proteins cannot cause cancer like the virus, but do elicit the production of antibodies, which protect the body from future infections. Gardasil contains viral-like proteins from HPV types 16, 18, 6, and 11 and only protects against infection from these HPVs. However, 70 percent of cervical cancers are caused by HPV types 16 and 18 and 90 percent of genital warts are caused by HPV types 6 and 11 (See Reference 3).
Efficacy
The National Cancer Institute stated that studies have demonstrated that Gardasil prevents almost 100 percent of precancerous cervical cell growth that is caused by the particular HPV types that the vaccine targets (See Reference 3). The NCI also reported that widespread vaccination could reduce the deaths attributable to cervical cancer by two-thirds and significantly decrease medical care costs associated with biopsies and invasive surgical procedures that are required to remove abnormal cervical cell growths (See Reference 3). The CDC stated that the vaccine is most effective when administered in 3 doses and in girls that have not been previously sexually active. Although, women who have not already been infected by all HPV types contained within the vaccine are protected against the remaining viruses.
Safety
The FDA and CDC utilize the Vaccine Adverse Event Reporting System to closely monitor adverse effects associated with vaccines (See Reference 1). Between the dates of approval of Gardasil and December of 2008, 12,424 adverse events were reported and 94 percent of these were considered not to be serious (See Reference 4). The most common side effects reported were pain and redness at the site of injection, nausea dizziness, headache and fainting. The incidence of adverse events reported was approximately 54 per 100,000 distributed doses. 32 deaths were reported, but the CDC stated there was not a pattern to suggest they were caused by the vaccine.
