Boys vaccinated against HPV have nearly half the chance of developing an HPV-related cancer as adults compared to those who were not vaccinated. That is the conclusion of a study published in JAMA Oncology in April 2026, covering more than one million men and representing the largest investigation of this question to date. The finding carries political weight: worldwide, HPV vaccination is still recommended primarily for girls and women, even though HPV causes more than 90 percent of all anal cancers and over 70 percent of cancers of the throat and oropharynx.
The Study in Detail
Researchers compared 510,260 vaccinated with 510,260 unvaccinated men aged 9 to 26, following them for up to ten years. The groups were made comparable through statistical adjustment. Result: vaccinated men had 46 percent fewer HPV-related cancers overall than unvaccinated men. Among boys vaccinated between ages 9 and 14, the risk fell by 42 percent. Among men vaccinated later, between ages 15 and 26, the reduction reached 50 percent, because cancer rates in that age group are higher overall and the absolute protective effect is therefore more measurable.
The study evaluated only the nonavalent HPV vaccine, which protects against nine different HPV types and is currently the standard vaccine. Approved in 2015, it is marketed globally as Gardasil 9.
Which Cancers Are Affected?
HPV is not a single virus but a family of more than 200 related viruses. Some are harmless to humans; others cause cancer. In men, the most affected are:
- Oropharyngeal cancer: over 70 percent of cases are caused by HPV, a share that has been rising for decades.
- Anal cancer: over 90 percent of cases are HPV-related.
- Penile cancer: over 60 percent of cases are HPV-associated.
Oropharyngeal cancer in particular has increased in many Western countries over recent decades, especially among middle-aged men. That trend is directly linked to rising HPV infection rates.
Long Neglected: Men as a Vaccination Target
The HPV vaccine was originally developed primarily for girls because of its protection against cervical cancer. But men are carriers of the virus and develop HPV-related cancers themselves. Several countries, including Germany and Australia, have extended vaccination recommendations to boys, but many nations still prioritize girls or implement male vaccination programs far less effectively.
From a herd immunity perspective, this is a problem: HPV spreads sexually. If only women are vaccinated, men remain a reservoir for the virus and unprotected against their own cancer risk. The new study confirms on a large scale what researchers have long suspected: the protection works as well in men as in women.
What This Means in Practice
According to the American Cancer Society, fewer than half of boys eligible for vaccination in the United States were fully vaccinated against HPV in 2023, while the rate for girls was considerably higher. Similar gaps exist in many other countries. The new data will likely increase pressure on health authorities to strengthen outreach campaigns for male adolescents.
The World Health Organization reinforced its global HPV vaccination recommendations on April 15, 2026, explicitly including boys. Whether and how quickly countries without male vaccination programs adopt comparable policies will shape HPV-related cancer rates for decades to come.
Study Limitations
As with any observational study, absolute causality cannot be established. The researchers used statistical methods to make the groups comparable, but unknown confounding factors cannot be fully excluded. The study also draws on data only from countries with structured vaccination programs. Long-term data beyond 25 or 30 years are not yet available, as the nonavalent vaccine was introduced only in 2015.
Nonetheless, a study covering more than one million participants followed for up to ten years is exceptionally large by medical research standards. The finding is statistically robust and adds important evidence to the case for extending HPV vaccination programs to boys globally.