What to Know About the HPV Vaccine and Cancer Prevention

Nearly 20 years after the first vaccine against human papillomavirus became available, many eligible Americans still are not getting the shot — even though it provides powerful protection against the leading cause of cervical cancer and a strong risk factor for anal cancer.

HPV is the most common sexually transmitted infection in the United States, and while most infections are asymptomatic and clear up on their own within two years, a small number persist and can cause cancer. HPV causes nearly all cases of cervical cancer, and can also lead to penile, anal, oral, vulvar and vaginal cancers.

The HPV vaccine, delivered as two or three doses, can significantly cut the risk of infection. It “is really one of the most effective vaccines we have,” said Dr. Lauri Markowitz, the HPV team lead in the Centers for Disease Control and Prevention’s division of viral diseases. But uptake remains stubbornly low: A report released by the C.D.C. this month showed that in 2022, only 38.6 percent of children ages 9 to 17 had received at least one dose of the HPV vaccine. Other new research suggests that HPV vaccination rates stalled in the wake of the coronavirus pandemic.

A study published this week laid out some of the primary reasons cited by parents in the United States who don’t plan to vaccinate their children against HPV, including safety concerns, a lack of knowledge about the vaccine and a belief that it isn’t necessary.

“We are still facing an uphill battle from what I would call inappropriate messaging or incomplete messaging when the vaccine rolled out about why this is so important,” said Karen Knudsen, chief executive of the American Cancer Society.

How does the vaccine work?

The HPV vaccine fools the body into thinking it has come into contact with the virus, marshaling antibodies in defense. Those antibodies can help clear the virus and prevent infection if someone is later exposed, which can happen through oral, anal and vaginal sex.