Men infected with HPV16, the type responsible for most HPV-related cancers, are 20 times more likely to be re-infected with the same type of HPV after one year. That is according to a new study published this month in the Proceedings of the National Academy of Sciences. The article shows the same effect in both men who are sexually active and celibate, suggesting that they are not reacquiring the virus from another sexual partner.
HPV is the most common sexually transmitted infection. It is estimated that 79 million Americans are currently infected by HPV, and most don’t know they have it. There are often no symptoms and the virus goes away on its own without causing health issues. Vaccination can protect against as many as nine of the most common types of HPV, but there are more than 200 genetically distinct HPV types.
The new study took a closer look at the many types of HPV and why they coexist. The research team, including Anna R. Giuliano, PhD, co-director of the Center for Infection Research in Cancer at Moffitt Cancer Center, analyzed data from the human papillomavirus in men (HIM) study, which tracked more than 4,000 unvaccinated men in Florida, Mexico and Brazil over a five-year period.
The new analysis of the HIM study data suggested the diversity of HPV types may stem from recurring infections of particular types within individuals. While only a small number of people are infected with any one type, the high overall HPV prevalence occurs because nearly half the adult population carries at least one type of HPV. The risk of reinfection is high, possibly due to auto-inoculation, spreading the infection by repeated contact between different sites on the body, or reactivation of a latent virus, or both.
The study was supported by grants from the National Institutes of Health (F30AI124636 and T32GM007281). Additional authors include Sylvia L. Ranjeva, Edward B. Baskerville, Greg Dwyer and Sarah Cobey from the University of Chicago; Vanja Dukic from the University of Colorado; Luisa L. Villa from the Universidade de São Paulo in Brazil; and Eduardo Lazcano-Ponce from the Instituto Nacional de Salud Pública in Mexico.
Source: Moffitt Cancer Center