Widespread vaccination against cervical cancer could reduce the need for burdensome screenings, U.S. and Finnish researchers said on Tuesday.
A study published in the journal Lancet Oncology show that GlaxoSmithKline’s Cervarix vaccine, which protects against two strains of human papillomavirus, or HPV, was more than 93 percent effective in preventing precancerous lesions in women who had never been infected and completely protected young women from the strains of virus targeted by the vaccine. The vaccine also reduced cancer risk for women who had already been infected by HPV, but was far less effective.
A second study found that Cervarix can protect against rarer strains of HPV that also cause cancer. Neither study looked at Gardisil, the other licensed HPV vaccine, which protects against four strains of HPV—including the two targeted by Cervarix.
The efficacy of vaccination adds fuel to two debates: how often women need to undergo cervical cancer screenings, and how important it is to reach girls—and boys—with HPV vaccinations before they become sexually active.
The U.S. Preventive Services Task Force, American Cancer Society, and other clinical groups have agreed that the pap smear—the screening for cervical cancer—does not need to be done every year for most women, and suggest that screenings begin at age 21. For vaccinated women, the need for screening might be further reduced.
“Provided that organised vaccination programmes achieve high coverage in early adolescents before sexual debut, HPV vaccination has the potential to substantially reduce the incidence of cervical cancer, probably allowing modification of screening programmes … when conducted alongside vaccination strategies,” Matti Lehtinen of the University of Tampere, Finland, wrote in one of the studies, which followed 20,000 young women.
"We believe that increasing coverage, particularly of sexually naive adolescent females, is now the most important public-health issue in HPV vaccination efforts," Mark Schiffman and Sholom Wacholder of the National Cancer Institute wrote in a commentary.
The Centers for Disease Control and Prevention already recommends that young girls receive HPV vaccinations before they become sexually active—ideally, at age 11 or 12.
The Advisory Committee on Immunization Practices, which advises the CDC, also recommends that young boys receive the vaccine, in order to protect themselves and others from a range of cancers, including head and neck cancer and anal and penis cancer, all of which can be caused by HPV.
But not everybody's happy about children receiving vaccinations against a sexually transmitted disease, even if it's a disease that causes cancer. Rep. Michele Bachmann, R-Minn., caused a ruckus on the presidential campaign trail two months ago when she alleged that the HPV vaccine might cause mental retardation and condemned those who would force a "government injection" upon “innocent little 12-year-old girls."
Cervical cancer kills 4,000 women each year.