HPV Might Be a Sperm Killer

Young men might have another reason to get their HPV vaccine. New research this month has found that men infected by high-risk strains of the human papillomavirus have increased counts of dead sperm compared to others. The findings suggest that HPV can potentially worsen men’s fertility, the researchers say.

HPV is an incredibly common sexually transmitted viral infection, with just about every person expected to catch it during their lifetime. But there are more than 200 types of the virus out there, and there are important differences between them. Some types will cause no problems at all, while others will cause unseemly, if not dangerous, symptoms like genital warts. But high-risk HPV types can linger in the body, triggering changes in infected cells that raise the odds of several different cancers. High-risk HPV infections cause nearly all cervical cancer cases in women, but also cause the majority of penile cancer cases in men as well as most anal, throat, and mouth cancers in both men and women.

Scientists in Argentina conducted this latest research, hoping to better understand how high-risk HPV infections can affect men’s health. They analyzed sperm samples from over 200 men who visited the same urology clinic sometime between 2018 to 2021. About 20% of these men tested positive for HPV, with 20 clearly positive for a high-risk HPV infection.

Using conventional tests, the researchers initially found no major difference in sperm quality between the men with and without high-risk HPV. But their more sensitive testing found that high-risk HPV cases tended to have a higher percentage of dead sperm compared to men with low-risk HPV or no infections. High-risk HPV men were also more likely to have lower levels of white blood cells in their semen, along with greater oxidative stress. The team’s findings were published this month in Frontiers in Cellular and Infection Microbiology.

“We concluded that men infected with HR-HPV, but not men infected with LR-HPV, show increased sperm death due to oxidative stress and a weakened local immune response in the urogenital tract,” said senior study researcher Virginia Rivero, a professor at the Universidad Nacional de Córdoba in Argentina, in a statement from Frontiers, publishers of the study. “These results suggest that HR-HPV positive men could have impaired fertility.”

The findings are based on a very small sample size of men who might not represent the general population. So more research will be needed to confirm whether high-risk HPV can actually harm men’s sperm quality and fertility on a population level. The researchers also plan to investigate whether having other STIs in addition to HPV can further hamper men’s reproductive health.

Given the already well-known risks of these infections, though, getting any protection against infertility from the HPV vaccine would only be icing on the cake. The newest HPV vaccines are intended to prevent infections from the most common wart- and cancer-causing types. Currently, all children and young adults in the U.S. under the age of 26 are recommended to receive HPV vaccination (two or three doses depending on age), though people as old as 45 may still benefit from it.