The subject of vaccines can raise emotional responses in some circles, and the Merck vaccine for cervical cancer, Gardasil, is no exception. The fact that the vaccine targets a sexually transmitted virus, the human papilloma virus (HPV), and the vaccine is given to girls as young as nine adds to the controversy.
Questions about the necessity, expense and safety of the HPV vaccine have fueled media attention on this fairly new vaccine. Given in three injections over a period of six months, the full vaccine costs about $360, much more than most other vaccines. Some physicians question the cost benefit of Gardasil considering that not all young women who become infected with HPV will go on to develop cervical cancer.
The vaccine targets four subtypes of HPV that have been shown to cause mutations in cells of the cervix as well as benign genital warts. While HPV infection is clearly linked to the development of cervical cancer, it’s not completely understood how the viral infection promotes cancer formation in some women and not in others.
Since the vaccine was approved in 2006 for girls and young women between the ages of nine to 26, nearly 16 million doses have been distributed in the U.S. About 25% of the nation’s teenage girls were vaccinated in 2007.
“For a new vaccine, 25% is really very good,” stated Lance Rodewald of the National Centers for Disease Control (CDC) in a Los Angeles Time article. “We need to see that rate every year if we are going to meet our goal of having 90% of teenagers (protected against cervical cancer),” he added.
Gardasil is a preventative vaccine; it has to be given before a girl or woman is exposed to the strains of HPV that are known to cause cervical cancer. That’s why the FDA and CDC authorize its use to girls before they become sexually active. As more young girls are vaccinated and become immune to the virus, medical researchers believe that the number of women diagnosed with cervical cancer will eventually drop.
Isolated reports of girls becoming serious ill or dying after receiving the shots raised concerns and fueled fears that the manufacturer should re-evaluate the risks of taking this vaccine. However, it’s difficult to know if the vaccine was truly the cause of the reported health issues. Experts believe almost all reports of serious adverse effects occurred by chance around the time a patient received the vaccine.
Since 2006, “the great majority (94%) of adverse events (reported to the manufacturer) have not been serious. These include fainting, pain at the injection site, headache, nausea and fever,” states the CDC, the governmental agency that monitors health problems and epidemics throughout the United States.
A more careful review of the 6% of reported cases involving serious illness or death, led the CDC to conclude that there was no common pattern linking those incidents to the vaccine.
“Gardasil continues to be safe and effective, and its benefits continue to outweigh its risk. We will continue to closely monitor the safety of Gardasil, that will potentially benefit the health of millions of women by providing protection against HPV,” according to the CDC website.
Up to 12,000 women are diagnosed with cervical cancer each year in the U.S., and nearly 4,000 women die annually from the disease.
Article Links:
US Food & Drug Admin., 2008. “Information from the CDC and FDA on the Safety of Gardasil Vaccine,” : http://www.fda.gov/CBER/safety/gardasil071408.htm
Maugh, T., 2008. “25% of girls vaccinated for cervical cancer, US study says.” LA Times article: http://articles.latimes.com/2008/oct/10/science/sci-gardasil10
Related Links:
Mayo Clinic, 2009: z’Cervical Cancer Vaccine: Who Needs It and How it Works,”
http://www.mayoclinic.com/health/cervical-cancer-vaccine/WO00120