|
Quarter of American Women 14-59 May Have HPV, Some Forms of Which Are Tied to Cervical Cancer
By Jaclyn Eisenberg
Human papillomavirus (HPV) is known to be the causative agent of cervical cancer, and nearly one-quarter of the female population, ages fourteen through fifty-nine, may have the sexually transmitted infection human papillomavirus (HPV). These data, reported in the February 28 issue of the Journal of the American Medical Association (Dunn et al, "Prevalence of HPV Infection Among Females in the United States"), are the first to provide a national estimate of HPV infection that accurately represents the extent of HPV infection in American women.
This study confirms the commonly accepted wisdom that HPV is the most prevalent sexually transmitted infection in the United States. In fact, the authors of the study state, "Our data indicate that the burden of prevalent HPV infection among women was higher than previous estimates." When extrapolated to the current U.S. population, these numbers mean that nearly 25 million women are currently infected with HPV. The prevalence of infection increases significantly in women with each year from fourteen to twenty-four years of age, peaking at 45% in women ages twenty to twenty-four. In women older than twenty-four, however, the authors noted a gradual decline in infection rates.
Fortunately, most of the hundred-odd strains of HPV are harmless; this is good news considering nearly 50% of American women can expect to be infected at some point in their lives. However, in addition to causing genital warts, the more virulent strains can also cause cervical and anal cancer (HPV is believed to be responsible for 99% of cervical cancers). Gardasil, Merck's recently approved and much-debated vaccine for HPV, targets the two types of the virus responsible for 90% of genital warts cases, as well as two types that are responsible for 70% of cervical cancers. These four types together (6, 11, 16, and 18) were detected in 3.4% of the study's participants, translating to a whopping 3 million American women.
Released on the heels of the heated debate surrounding the possibility of mandating Gardasil vaccinations in young girls, these numbers simply underscore the importance of this vaccine from a public health perspective. Despite controversies over when to administer the vaccine, this study makes the case that 3 million American women (and millions more men and women worldwide) can potentially benefit from Gardasil's administration. Concerns voiced by some that this vaccine might promote early sexual activity seem unscientific and more politically-based than public-health-generated. As has been previously proven, preventative measures taken against STDs do not increase the likelihood of sex.
As for the timing of the shots: if the immunity produced by the vaccine wanes after several years, a booster would likely be effective at that time. Further research also needs to be done on the possible benefits of giving the vaccine to boys as well, both to protect them from HPV-induced genital warts and to reduce the likelihood of transmission of the cancer-causing varieties to their female partners.
A related Journal of the American Medical Association editorial underscores the need for continued research on the prevalence of HPV in women older than twenty-six. The CDC currently recommends the vaccine for girls eleven and twelve years old and encourages "catch-up vaccinations" for women between thirteen and twenty-six years of age. Further research could reveal if the strains of HPV common in older women are the same as those most common in the younger population, therefore helping to determine whether older women will benefit from this vaccine.
Jaclyn Eisenberg is a research associate at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).
|
