HPV vaccine does not encourage less common HPV strains, study finds
|July 26, 2012|
A new study led by researchers at UNC Gillings School of Global Public Health strengthens the argument for human papillomavirus (HPV) vaccination in men. The research showed that the vaccine, which targets the two most common strains of the virus (HPV 16 and 18) likely would not cause other cancer-causing HPV strains to develop and thrive in a vaccinated person.
Jennifer Smith, PhD, research associate professor of epidemiology at the School and member of the UNC Lineberger Comprehensive Cancer Center, is the study’s senior author.
Published June 18 in the Journal of Infectious Diseases the study examined a group of 2,228 Kenyan men in a “nested” trial within a larger study and found little evidence for potential HPV type competition. Viral type competition occurs when different types of a particular virus compete for dominance.
The study presents the first epidemiological data in men on the type-specific associations between prevalent HPV infections and future acquisition of other HPV types.
The virus is the primary cause of cervical cancer in women and is responsible for genital cancers, including anal and penile carcinoma, in men. Between 20 and 73 percent of males infected with HPV have been observed to be co-infected with multiple HPV types. Such multiple infections have been associated with acquisition of other HPV types and increased HPV persistence in men and cervical precancerous lesions in women.”We found no evidence for competition between different HPV types over time in high-risk men from Kenya,” Smith said. “While these data are based only upon non-vaccinated men, our findings are of potential importance because they suggest that HPV types generally are acting independently from one another. Thus, it is unlikely that HPV type-replacement will occur following large-scale vaccination programs of young male adolescents.”
The U.S. Centers for Disease Control and Prevention (CDC) recommends HPV vaccination to teenage girls and, more recently, to teenage boys. With the recent approval of prophylactic HPV vaccination of young men, data are needed to understand if patterns of HPV acquisition differ among men with specific HPV type infections as compared to men without these HPV infections. The effect of current vaccine-relevant HPV infections on the subsequent acquisition of different HPV types could impact the long-term potential for HPV type replacement following population-based HPV vaccination.
Other UNC authors are Anne Rositch, PhD, now a postdoctoral fellow in epidemiology at Johns Hopkins University; Michael Hudgens, PhD, associate professor of biostatistics at the public health school; and Danielle Backes, PhD, now a postdoctoral fellow at Brown University. Other authors are from the universities of Nairobi, Illinois and Manitoba; Johns Hopkins Bloomberg School of Public Health; and the Vrije Universiteit Medical Center in Amsterdam, the Netherlands.
Funding for the research was provided by the National Institutes of Health and its National Cancer Institute, UNC Center for AIDS Research, Canadian Institutes of Health Research and a National Institutes of Health predoctoral training grant.