CHICAGO — Giving the human papillomavirus vaccine to boys and men reduces their risk of head and neck cancer and other malignancies, a new analysis shows, adding to the vaccine’s proven effectiveness in protecting women against cervical cancer.
The researchers said the study, which involved more than 3.4 million people, is one of the first to analyze the vaccine’s actual effectiveness over time in preventing HPV-related cancers of the head and neck, anus, penis, vulva, vagina and cervix.
Vaccine research to date has focused primarily on cervical cancer: One large Swedish study in 2020, for example, found that the incidence of cervical cancer was 47 cases per 100,000 among vaccinated women, compared with 94 cases per 100,000 among unvaccinated women.
The new study, to be presented at the American Society of Clinical Oncology meeting in Chicago, involved more than 1.7 million volunteers between the ages of 9 and 39 who had received the HPV vaccine since 2010, as well as a similar number of similar unvaccinated volunteers. About 44% were men.
Vaccinated men had lower rates of all HPV-related cancers and head and neck cancer (3.4 and 2.8 cases per 100,000 vaccinated patients, respectively, compared with 7.5 and 6.3 cases per 100,000 unvaccinated patients, respectively), the study found.
Smoking was once the main cause of many head and neck cancers, including oral and pharyngeal cancers, but HPV infection is now the main culprit, Dr. Lynn Schuchter, president of the American Society of Clinical Oncology, said at a news conference Thursday, Dr. Schuchter, who was not involved in the study.
The new study “expands our knowledge” and shows that preventing infection with the vaccine can help prevent these HPV-related cancers, she added.
In this study, vaccinated women had a lower risk of all HPV-related cancers and, as expected, a lower risk of cervical cancer compared to unvaccinated women.
Vaccination did not significantly reduce the risk of head and neck, vulvar, or vaginal cancer.
Merck’s HPV vaccine was approved for girls and women ages 9 to 26 in 2006, and for boys and men in the same age group in 2009. The latest version, Gardasil 9, has been approved for use in children and adults ages 9 to 45 in the U.S. since 2018.
According to another study to be presented at the conference, between 2011 and March 2020, HPV vaccination rates in the U.S. increased from 23.3% to 43% of the eligible population, improving from 7.8% to 36.4% among men and from 37.7% to 49.4% among women.
