The prevalence of four HPV types that cause most genital warts and cervical cancers is comparable among unvaccinated, sexually experienced men who have sex with men, or MSM, and women, according to recently published study findings.
Research showed both groups had significantly higher HPV seroprevalence than men who have sex only with women (MSW) — a difference that may be explained by biological characteristics at the anatomic site where patients are exposed, Rayleen M. Lewis, MPH, a researchers from the CDC’s Division of Viral Diseases and contractor at Synergy America, Inc., and colleagues wrote.
HPV is the most common STD in both men and women, the researchers noted. Vaccination can protect against multiple types of HPV, including the two (6 and 11) that cause most genital warts and the two (16 and 18) that cause most cervical cancers.
According to Lewis and colleagues, antibody development after HPV infection differs among women and varies by HPV type, though seroconversion may provide protection against later infection of the same type. Seroconversion is rarer in men than in women, they noted, with little evidence that they are naturally protected from subsequent infections.
“Differences in HPV seroprevalence by sex have been observed, likely due to differences in the anatomic site of HPV exposure. Seroconversion may be more likely after exposure at nonkeratinized (mucosal) compared to keratinized epithelium,” Lewis and colleagues wrote. “We compared seroprevalence among self-identified gay/bisexual MSM and females, two groups more likely exposed at the mucosal epithelium, and MSW, a group likely exposed primarily at keratinized epithelium, using data from the [CDC’s] National Health and Nutrition Examination Survey from 2003 to 2010.”
For the study, Lewis and colleagues estimated the weighted seroprevalence of HPV 6/11/16/18 among MSM, MSW and women aged 18 to 59 years who were unvaccinated and sexually experienced. According to the authors, seroprevalences were compared using prevalence ratios adjusted for sexual behavior.
Results of the study showed that HPV seroprevalence among MSM and women was comparable at 42.6% and 37.1%, respectively. Seroprevalence among MSW was 13.2%. Additionally, the researchers found that seroprevalence increased with the number of lifetime sexual partners in all groups.
“Few studies have been able to estimate serology separately for MSM, MSW, and females. Even after accounting for sexual behavior, we found significant differences in HPV seroprevalence that may be explained by biological characteristics at the anatomic site of exposure,” Lewis and colleagues concluded. “If naturally acquired antibodies provide protection, variation in seroprevalence among these groups may indicate differences in susceptibility to future infection. Future research could explore whether differences in seropositivity following infection result in differential protection from future infection.” – by Caitlyn Stulpin
Disclosures: The authors report no relevant financial disclosures.