The human papillomavirus (HPV) is a group of many related viruses passed through sexual contact. A number of HPV strains can lead to the development of cervical cancer, as well as vulvar, vaginal, penile, anal, and oropharyngeal cancer, which occurs in the middle part of the throat.
Two strains – 16 and 18 – are responsible for 70 percent of all cervical cancer cases, with type 16 also causing the majority of other HPV-related cancers. Luckily, the HPV vaccine helps protect against the virus, lowering the risk of these cancers.
But who should be vaccinated, and when?
The U.S. Centers for Disease Control and Prevention (CDC) recommends boys and girls be vaccinated at 11 or 12 years old, to protect them from the virus prior to their first exposure. While the vaccine was originally recommended only for girls, as nearly all cervical cancers are HPV-related, vaccinating boys can also help protect them against penile, anal, and oropharyngeal cancers, while also reducing the spread of these viruses.
The CDC advises preteens to get two doses of the vaccine six months apart, while older teens and young adults should receive the previously recommended three-dose series.
The vaccine is recommended for children as young as 9, and for young women through age 26 and young men through age 21. Men who have had sexual content with other men, or who have compromised immune systems, may receive the vaccine through age 26.
Why isn’t the HPV vaccine recommended past age 26?
Experts urge young adults to get the HPV vaccine before 26, as it has yet to show benefit past that age. By age 26, many young adults have been exposed to HPV, rendering the vaccination ineffective, although not unsafe to receive.
“Whether the vaccine works in older patients has not been tested on a large scale so far,” says Robert Haddad, MD, disease center leader of Dana-Farber’s Head and Neck Oncology Program, who stresses the importance of vaccinating early, before any exposure to HPV. “The best age to vaccinate is 11 or 12, which is what I tell my patients with young kids.”
Individuals older than 26 who have not received the HPV vaccine should talk to their doctors about the best ways to protect against the virus, and should follow their doctors’ cancer screening recommendations – including regular Pap tests to screen for cervical cancer – to detect HPV-related cancers early.