Archive for December 2011
By: Rebecca Cerio
Vaccines are one of the great triumphs of modern medicine. The ability to give someone an injection and protect them from diseases that used to claim millions of lives each year at low cost is a huge step forward in public health. They have helped us to turn polio, tuberculosis, measles, smallpox, and dozens of other diseases from major killers into preventable hurdles easily overstepped by a visit to the doctor.
HPV: A Vaccine Success Story
The human papillomavirus vaccines (Gardasil from Merck and Cervarix from GlaxoSmithKline) are two of the newest vaccine successes. Both are safe, with nearly all adverse events reported being minor and no serious complications causally lined to the vaccines. Gardasil, the most widely-used of the two, protects against infection with HPV 6, 11, 16, and 18, which are responsible for most types of cervical cancer and some vulvar, vaginal, head and neck, and anal cancers. Gardasil also protects against genital warts caused by HPV 6 and 11. In one of its major clinical trials, Gardasil’s ability to protect against cervical cancer was so overwhelmingly evident that the trial was stopped early on ethical grounds…so that women in the control group could also be given the vaccine.
Gardasil is a preventative vaccine and thus cannot prevent against any disease if it is given after initial HPV infection. Since HPVs are ubiquitous and extremely common sexually transmitted viruses, Gardasil and Cervarix are both most effective if given before sexual activity begins. Gardasil has been approved for use in adolescent girls for several years, but uptake has been sluggish.
There has been some use of the vaccine among college-age women, but depending on when sexual activity begins, this may be too late to prevent infection. Additionally, convincing young people of the dangers of cervical cancer, which usually only affects women decades after HPV infection, presents its own challenges.
The Cervical Cancer Vaccine: Not Just For Girls Anymore
HPV vaccination is remarkably effective at preventing new HPV 6, 11, 16, and 18 infections, and the CDC’s Advisory Committee on Immunization Practices has recommended these vaccinations as a public health measure for girls age 11 and up. Most recently, they have also recommended vaccination for boys. The rationale for giving boys a vaccine against cervical cancer is severalfold:
- Vaccination will protect boys from anal and possibly head and neck cancers.
- Gardasil can prevent genital warts in males as well as females.
- Prevention of HPV16 and 18 infection in men will prevent those men from infecting others and thus protect their unvaccinated male and female sexual partners.
The Choice Is Ours
Whether the CDC’s recommendation will cause a significant uptake of the HPV vaccines among adolescent boys is unclear. There are several concrete benefits to males being vaccinated, but the vaccination price and scheduling may hinder vaccination efforts. The recommended vaccination course costs almost $400 and requires three separate injections over 6 months (though recent studies have suggested that two doses give the same level of protection and even one dose gives some protection). There has also been some pushback from parents and social groups who are uncomfortable with vaccinating pre-teens of either sex for a sexually transmitted disease.
The slow uptake of the HPV vaccines is disheartening, considering its effectiveness. However, with over 40 million doses of Gardasil alone administered, we are already on our way to making the vast majority of cervical cancers a thing of the past. With the success of HPV vaccination, we have taken a huge scientific step. As Dr. William Schaffner of Vanderbilt University School of Medicine points out in a recent New York Times article, “This is cancer, for Pete’s sake. A vaccine against cancer was the dream of our youth.”
- Centers for Disease Control and Prevention, Vaccines and Preventable Diseases website. http://www.cdc.gov/vaccines/vpd-vac/default.htm
- Centers for Disease Control and Prevention, Reports of Health Concerns Following HPV Vaccination webpage. http://www.cdc.gov/vaccinesafety/vaccines/hpv/gardasil.html
- Centers for Disease Control and Prevention, HPV Vaccination webpage. http://www.cdc.gov/vaccines/vpd-vac/hpv/default.htm
- Harris, Gardener. ”Panel Endorses HPV Vaccine for Boys of 11″. New York Times online edition, October 25, 2011. Accessed 12/7/11. http://www.nytimes.com/2011/10/26/health/policy/26vaccine.html.
- “NIH study finds two doses of HPV vaccine may be as protective as full course”. National Institutes of Health press release, September 9, 2011. http://www.nih.gov/news/health/sep2011/nci-09.htm