For over a decade, there has been a vaccine to prevent the types of human papillomavirus (HPV) that are most likely to cause cervical and other types of cancers -- and yet, vaccine rates lag far behind the Healthy People 2020 goal of 80%among 13 to 15 year olds. In 2017, just 49% of eligible young people had been adequately vaccinated. This is particularly alarming given new research that suggests vaccines could prevent 92% of all cancers caused by HPV.
A new article in JAMA Pediatrics looked at two factors that might impact vaccination rates -- knowledge of HPV itself and recommendations from a health care provider. It found that a majority of adults of all ages do not understand the connection between HPV and cancer. Moreover, it found that few people are receiving vaccine recommendations from their provider. Women were both more knowledgeable about HPV and more likely to receive a recommendation, which is likely a result of the early campaigns that tied HPV and the vaccine to cervical cancer.
HPV is actually a group of more than 100 related viruses that can infect various parts of the body. There are 40 types of the virus that are known to be spread through sexual activity. The Centers for Disease Control and Prevention (CDC) estimates that 79 million people in the United States are infected with sexually transmitted HPV, and 14 million new infections occur annually. Though most people won't suffer long-term health consequences and may never even know they have the virus, others may develop cervical cancer or cancers of the head, neck, throat, genitals, or anus.
Certain types of the virus are known to cause these and other health issues. Specifically, types 6 and 11 cause most cases of genital warts, and types 16 and 18 cause 70% of cervical cancer cases. The newest version of the HPV vaccine, called Gardasil 9, protects against these four types as well as five other high-risk types (31, 33, 45, 52, and 58).
A study published this summer in the CDC's Morbidity and Mortality Weekly Report (MMWR) found that between 2012 and 2016, there were an average of 34,800 cancers attributable to HPV reported each year. After analyzing data on these cases, the authors concluded that the majority of these cancers (92%) are, in fact, caused by types of the virus that are covered by Gardasil 9. This means that 32,100 cancers each year could be prevented if vaccine recommendations were followed. In a statement announcing the study, Admiral Brett P. Giroir, M.D., assistant secretary for health at the U.S. Department of Health and Human Services, noted: "A future without HPV cancers is within reach, but urgent action is needed to improve vaccine coverage rates."
The HPV vaccine is given as a series of two shots, six months apart. The CDC recommends that all young people get the HPV vaccine as part of routine vaccination at age 11 or 12 years, though young people can start the vaccine process at age 9. The CDC also recommends the vaccine for young women 13 to 26 and young men 13 to 21 who have not been adequately vaccinated previously. In addition, vaccination is recommended for men who have sex with men, transgender individuals, and immunocompromised individuals (including those living with HIV) through age 26. In 2018, the Food and Drug Administration expanded approval of Gardasil 9 to allow it for use in adults ages 27 through 45.
Vaccination rates are rising slowly among young people. An MMWR report for 2017 found that 66% of adolescents ages 13 to 17 had received the first dose of the vaccine and almost 49% had received both necessary doses. The research found that more girls (53%) than boys (44%) had received the vaccine -- which, again, likely reflects the original focus on cervical cancer and vaccinating young women.
Unfortunately, as the JAMA Pediatrics study confirms, most adults do not understand the connections between HPV, cancer, and the vaccine. For the study, researchers looked at data from two cycles of the Health Information National Trend Survey (HINTS-5) conducted in 2017 and 2018. A total of 2,564 men and 3,697 women responded to HPV knowledge questions in HINTS-5. The researchers broke out responses by age groups, looking at 18 to 26 year olds (a group that has always been vaccine-eligible), 27 to 45 year olds (a group that became vaccine-eligible last year), and those over 45 (who are not eligible for the vaccine). The results found that regardless of age or sex, 70% of adults did not know that HPV causes oral, anal, and penile cancers.
Among those 18 to 26, 54% of men and 80% of women said that they had heard of HPV, and 53% of men and 79% of women said they had ever heard of the HPV shot or cervical cancer vaccine. Still, 60% of men and 31% of women did not know HPV caused cervical cancer. In addition, 92% of men and 79% of women did not know HPV caused anal cancer; 89% of men and 78% of women did not know it caused penile cancer; and 85% of men and 77% of women did not know HPV caused oral cancers.
Among those 27 to 45, 68% of men and 86% of women said they had heard of HPV, and 56% of men and 81% of women said they had ever heard of the HPV shot or cervical cancer vaccine. In addition, 47% of men and 24% of women did not know HPV caused cervical cancer; 80% of men and 75% of women did not know it caused anal cancer, 81% of men and 72% of women did not know it caused penile cancer; and 82% of men and 73% of women did not know HPV caused oral cancers.
Among those over 45, there was a notable lack of knowledge about HPV and the HPV vaccine at all, with 55% of men and 35% of women saying they had not heard of HPV, and 55% of men and 30% of women saying they had not heard about the HPV shot or cervical cancer vaccine. This group was also largely unaware of the connection between HPV and various cancers. The results found that 66% of men and 46% of women did not know HPV caused cervical cancer; 87% of men and 82% of women did not know it caused anal cancer; 85% of men and 79% of women did not know it caused penile cancer; and 86% of men and 80% of women did not know HPV caused oral cancers.
The findings among this age group are important, despite the fact that they are too old to receive the vaccine themselves. Kalyani Sonawane, Ph.D., assistant professor at University of Texas Health School of Public Health and the study's co-lead author, explained in a statement: "Low levels of HPV knowledge in these older age groups is particularly concerning, given that these individuals are (or will likely be) parents responsible for making HPV vaccination decisions for their children."
The results also found that very few men (19%) and women (32%) had received a recommendation from a health care provider for the HPV vaccine for themselves or their children.
Ashish Deshmukh, Ph.D., M.P.H., an assistant professor of public health at the University of Texas Health Science Center at Houston and the study's co-lead author, said in a statement: "The lack of knowledge may have contributed to low HPV vaccination rates in the United States." Deshmukh believes that most vaccine decisions are based on knowledge. He said in a statement: "HPV vaccination campaigns have focused heavily on cervical cancer prevention in women. … Rates of cervical cancer have declined in the last 15 to 20 years because of screening. On the other hand, there was a greater than 200% increase in oropharyngeal cancer rates in men and a nearly 150% rise in anal cancer rates in women." He concluded: "Our findings demonstrate a need to educate both sexes regarding HPV and HPV vaccination."