Demographic, Behavioral Factors in Non-Vaccine HPV Infections in Sexually Active Women and Teens
Published December 19, 2017 | Vaccine
Concerns have been raised that human papillomavirus (HPV) vaccine introduction in communities may lead to type replacement, an increase in non-vaccine-type HPV due to the “ecological niche” created by the reduction in vaccine-type HPV. Differences in the risk factor profiles of vaccinated and unvaccinated women also play a role, according to recent findings from the Division of Adolescent and Transition Medicine.
The HPV vaccine was introduced in the U.S. in 2006. Since then, a team led by Jessica Kahn, MD, MPH, has been following the epidemiological impact in Cincinnati.
In 2016, the team demonstrated vaccine effectiveness as evidenced by a reduction in vaccine-type HPV among vaccinated women, and herd protection among unvaccinated women. However, the team also found an unexpected increase in non-vaccine-type HPV infections in unvaccinated women.
One possible explanation is type replacement. But the Cincinnati Children’s team had another hypothesis.
Co-authors Lili Ding, PhD, and Lea Widdice, MD, worked with Kahn to study data from 1,180 women. They found “significant differences” in demographic and behavioral characteristics between unvaccinated and vaccinated women that also appear to affect HPV risk.
For example, unvaccinated women treated at city-run clinics tended to be older and more likely to be uninsured. Unvaccinated teens seen at the hospital’s Teen Health Center were more likely to have multiple recent sex partners.
“Surveillance studies that examine changes in non-vaccine type HPV prevalence after vaccine introduction should exercise caution in attributing any increase in non-vaccine-type HPV to type replacement,” the study authors say.
