HPV vaccine prevents cancer in men and women

Cervical cancer is the most common type of female cancer and is caused by the human papillomavirus (HPV).

It is the fourth most common cancer among women worldwide, with about 660,000 new cases and about 350,000 deaths expected in 2022.

According to the U.S. Centers for Disease Control and Prevention (CDC), about 200,000 women in the country are diagnosed with precancerous conditions of the cervix each year. About 11,100 women are diagnosed with cervical cancer caused by HPV, and about 4,000 women die from the disease each year. HPV infections usually resolve within one to two years.

However, some strains of HPV can cause cancer in both men and women, accounting for 36,000 cases of cancer each year. Almost everyone will become infected with some strain of HPV during their lifetime, according to the CDC.

There is a vaccine against HPV that can prevent more than 90% of cancers associated with the virus. In 2022, however, only 38.6% of young people in the United States had received at least one of the two recommended doses of the vaccine. Despite the risks associated with HPV for both sexes, girls are more likely to be vaccinated against it than boys.

A new study has found that HPV vaccination can reduce the risk of HPV-related cancers by 56% in men and 36% in women.

The findings were presented at the annual meeting of the American Society of Clinical Oncology from May 31 to June 4 in Chicago, but have not yet been published in a peer-reviewed journal.

Daniel Ganjian, MD, a board-certified pediatrician at St. John's Medical Center in Santa Monica, California, who was not involved in the study, explained:

"The incidence of HPV-related cancers in men is significant. According to the CDC, about 4 out of every 10 HPV-related cancers occur in men, and more than 15,000 men develop HPV-related cancers each year in the United States. HPV can cause cancer in both women and men, with HPV-related throat cancer being more common in men and increasing rapidly in developed countries."

Effectiveness of HPV vaccine in preventing cancer

In women, HPV is associated with cervical, vaginal, and vulvar cancer. In men, HPV is associated with penile cancer. In both sexes, HPV can cause throat cancer, as well as anal cancer.

The HPV vaccine can prevent more than 90% of precancerous conditions of the vagina, cervix, and vulva, which include abnormal cells that can lead to cancer in the future.

The authors of the new study compared about 1.7 million people vaccinated against HPV with a similarly sized and age-matched group who were not vaccinated.

The researchers found that among vaccinated men, there were 3.4 cases of HPV-related cancer per 100,000 people, compared with 7.5 cases per 100,000 people among unvaccinated men.

For women, the difference was also significant: among vaccinated women, there were 11.5 cases of HPV-related cancer per 100,000 people, compared with 15.8 cases per 100,000 people among unvaccinated women.

Rachel Goldberg, a Los Angeles-based physician who was not involved in the study, commented on HPV vaccines:

"For decades, women have been told about the importance of Pap tests to detect early signs of disease," she said.

"Most women know at least one person who has had a minor procedure to remove abnormal cells thought to be related to HPV, often a woman in her 20s or 30s," Goldberg added.

Goldberg also noted an increase in HPV-related cancers among men, particularly those between the ages of 40 and 60.

Why is it important to increase HPV vaccination among children?

The CDC recommends that children receive two doses of the HPV vaccine beginning at age 11 or 12, although vaccination can begin as early as age 9.

For children who do not receive their first HPV vaccination by age 15, three doses are required for optimal protection.

"It is important to note that HPV vaccination prevents new HPV infections, but does not treat existing infections or disease. The vaccine works best when given before any exposure to HPV," Ganjian said.

Goldberg noted that some parents may delay vaccinating their children against HPV, believing that they are not yet sexually active.

"Over time, parents may feel it's too late, their child is out of their care, or they feel it won't affect their child because of his [or her] level of responsibility, not realizing how easily HPV spreads," Goldberg explained.

"The value of the HPV vaccine for men is known among physicians, but awareness and vaccination rates among men remain low," Ganjian said.

Goldberg also noted other misconceptions that may contribute to the stigma of HPV among young men.

"It is still primarily seen as a protective measure for girls, with some parents believing that vaccinating their sons is only necessary to protect their potential future partners," Goldberg added.

Demographic and social differences influence HPV vaccination rates

CDC statistics show that demographic characteristics may determine whether a child will be vaccinated against HPV.

For example, vaccination rates increase with age and are more common in families with higher socioeconomic status. In addition, children with disabilities are more likely to receive vaccinations than children without disabilities.

Hispanic children are less likely to be vaccinated than white children, and children living outside urban areas are less likely to receive the HPV vaccine.

"Research shows that there are racial and ethnic differences in knowledge of the HPV vaccine and trust in receiving cancer information from doctors," Ganjian said.

"This may contribute to fewer boys receiving the vaccine. In addition, physician communication practices and the level of trust in cancer information from physicians may influence HPV vaccine awareness," he concluded.