HPV vaccine prevents cancer in men, too, study being presented in Chicago at ASCO oncology conference finds

New research suggests the HPV vaccine prevents cancer in men as well as in women, but fewer boys than girls are getting the shots in the United States.

The studies released by the American Society of Clinical Oncology will be presented in Chicago at the organization's yearly meeting, which will bring 40,000 doctors to McCormick Place starting Thursday for one of the biggest medical conferences in the world.

The shot for HPV — the human papillomavirus — was developed to prevent cervical cancer in women. Experts credit the vaccine, sold under the brand name Gardasil, and improved screening with lowering cervical cancer rates.

It's taken longer to document the shots prevent HPV-related cancers in men, too. But the new research suggests that vaccinated men have fewer cancers of the mouth and throat compared to those who didn't get the shots. These cancers are more than twice as common among men as in women.

In the United States, the HPV vaccine has been recommended since 2006 for girls 11 or 12 years old and since 2011 for boys the same age. Catch-up shots are recommended for anyone up to 26 years old who hasn’t been vaccinated.

Parents of boys — not just girls — should know that HPV vaccines lower cancer risk, says Jasmin Tiro of the University of Chicago Medicine Comprehensive Cancer Center, who wasn't involved in the research.

And young men who haven't been vaccinated can still get the shots, she says: “It's really important that teenagers get exposed to the vaccine before they’re exposed to the virus,” she says.

For the new research, scientists compared information on 3.4 million people of similar ages — half of them vaccinated versus half unvaccinated — from a large health care dataset.

As expected, the vaccinated women had a lower risk of developing cervical cancer within at least five years of having gotten the shots.

For men, there were benefits, too. Vaccinated men had a lower risk of developing any HPV-related cancer, including cancers of the anus, penis and mouth and throat.

These cancers take years to develop, so the numbers were low. There were 57 HPV-related cancers among the unvaccinated men — mostly head and neck cancers — compared to 26 among the men who had gotten the HPV vaccine.

“We think the maximum benefit from the vaccine will actually happen in the next two or three decades," says Dr. Joseph Curry, a co-author of the study, who is a head and neck surgeon at the Sidney Kimmel Cancer Center in Philadelphia. “What we’re showing here is an early wave of effect.”

A second study published by the oncologists organization that's also being presented at the ASCO conference found vaccination rates rising but with the numbers of boys and young men lagging behind girls and young women in getting the HPV shots.

HPV is very common and is spread through sex. Most HPV infections cause no symptoms and clear up without treatment. But others develop into one of several types of cancer — causing about 37,000 cases a year, according to the federal Centers for Disease Control and Prevention.

For the second study, the researchers looked at self- and parent-reported HPV vaccination rates among preteens and young adults in a large government survey. From 2011 to 2020, the number of those vaccination rates among female patients rose from 38% to 49% and among male patients from 8% to 36%.

“HPV vaccine uptake among young males increased by more than fourfold over the last decade, though vaccination rates among young males still fall behind females,” says Dr. Danh Nguyen of the University of Texas Southwestern Medical Center in Dallas, who was a co-author of the study.