These types of HPV, called mucosal, or genital, types, are common and are spread through intimate skin-to-skin contact, with or without sexual intercourse, says Christine Nyquist, MD, the medical director of infection prevention and control and occupational health at the Children’s Hospital Colorado in Aurora. HPV infections usually clear on their own, but in some people the virus may persist. When that happens, the infection can lead to genital warts or to a variety of types of cancer, including cervical cancer, anal cancer, female genital cancers, penile cancer, and cancers of the mouth and throat, according to the National Cancer Institute (NCI). To prevent these cancers as well as genital warts, the Centers for Disease Control and Prevention (CDC) currently recommends that boys and girls receive the HPV vaccine when they’re 11 or 12 years old, which is likely before they’ve been exposed to mucosal types of HPV. When children aren’t vaccinated at the recommended time, they’re left vulnerable to getting cancer that could be prevented, says Dr. Nyquist. Here are eight essential facts about the HPV vaccine that all parents should know.
1. The HPV Vaccine Protects Against 9 HPV Types
The HPV vaccine currently being used in the United States, Gardasil 9 (human papillomavirus 9-valent vaccine) protects against nine strains of the virus, including the two strains that cause most genital warts, types 6 and 11, and seven that can lead to cancer: types 16, 18, 31, 33, 45, 52, and 58. An earlier version of Gardasil (human papillomavirus quadrivalent) protects against types 6 and 11, which cause genital warts, and the two top cancer-causing HPV types, 16 and 18. A third HPV vaccine Cervarix (human papillomavirus bivalent), which is no longer available in the United States, protects only against HPV types 16 and 18 and is approved for use only in girls. RELATED: What Are HPV 16 and 18?
2. The HPV Vaccine Works to Prevent Cancer and Warts
A variety of studies have shown that the HPV vaccine is effective against cervical infections, genital warts, and oral HPV infections. Despite low vaccination rates in the United States, six years after the 2006 approval of the vaccine, HPV infections of the cervix dropped by more than 64 percent among teens ages 14 to 19 and 34 percent among women ages 20 to 24, according to a study led by Lauri Markowitz, MD, a research epidemiologist in the division of STD prevention at the CDC in Atlanta, published in March 2016 in the journal Pediatrics. Australia, which has a high vaccination rate using Gardasil, has seen a dramatic decrease in the number of genital wart cases — an early consequence of HPV infection, according to Dr. Markowitz. A study published in January 2018 in Journal of Clinical Oncology showed that the HPV vaccine appears to be effective against oral HPV infections. The study of young adults in the United States found that the prevalence of oral infection with four HPV types, including two cancer-causing types, was 88 percent lower in those who reported receiving at least one dose of an HPV vaccine than in those who said they were not vaccinated. Oropharyngeal cancer is now the most common HPV-related cancer in the United States, according to an August 2018 article in Morbidity and Mortality Weekly Report. RELATED: Oral HPV Is a Growing Concern in Men
3. The HPV Vaccine Is Safe
All three HPV vaccines that are or have been used in the United States were tested extensively before they were approved by the Food and Drug Administration (FDA). In addition, both the FDA and CDC continue to monitor the safety of all vaccines after they are approved and made available to the general public. As of December 2017, about 29 million doses of Gardasil 9 had been distributed in the United States, and about 7,250 adverse events were reported, notes the CDC. The vast majority were not serious. Common side effects are pain, redness, or swelling in the arm where the injection was given; dizziness; fainting; nausea; fatigue; muscle or joint pain; and headache.
4. You Shouldn’t Wait to Vaccinate
Gardasil 9 can now be given to adults as old as 45. But the best time to vaccinate is well before there’s any exposure to the virus, because the vaccine prevents infection but doesn’t treat an existing one, Markowitz says. The HPV vaccine should be given in two doses when girls and boys are 11 to 12 years old, according to the latest recommendations from the CDC. Anyone who starts the vaccine series at 15 years or older will need three doses to reach optimal immunity. Individuals of any age who have a weakened immune system also need to receive three doses.
5. U.S. Vaccination Rates Are Slowly Rising
In 2017, roughly half (49 percent) of adolescents ages 13 to 17 years had received all recommended doses of the HPV vaccine, and 66 percent had received the first dose to start the vaccine series, according to the CDC. Those numbers were up from 2013, when 35 percent of boys and 57 percent of girls ages 13 to 17 had started the HPV vaccine series. And while any increase is good, Markowitz says the trend isn’t good enough. One problem, she says, is that some doctors aren’t recommending the vaccine. Two other common reasons, according to researchers from the Johns Hopkins Bloomberg School of Public Health in Baltimore, is that parents are concerned about the vaccines’ safety or don’t feel the vaccine is necessary. Their study results were published in November 2018 in the Journal of Adolescent Health.
6. The HPV Vaccine Does Not Lead to Promiscuity
While some adults have raised the concern that HPV vaccination will encourage risky adolescent sexual behaviors, so far, that does not appear to be the case. For example, a study published in September 2018 in the journal Pediatrics found that state legislation enacted to improve HPV vaccination coverage is not associated with changes in adolescent sexual behavior. The specifics of the legislation varied. Some states adopted measures to make the vaccine affordable and accessible, some mandated student or parent education about the HPV vaccine, and a few required that students in certain grades be vaccinated. According to Nyquist, “Parents ask children to put on seat belts to keep them safe in the event of an unexpected car accident. By putting on the seat belt, they aren’t inviting an accident. Similarly, vaccination keeps [children] safe for the future if they are exposed to HPV. It doesn’t invite sexual activity."
7. Vaccination Doesn’t Replace Cervical Cancer Screening
“The HPV vaccine protects against most HPV types that cause cervical cancer, but not all,” says Debbie Saslow, PhD, the senior director of HPV-related and women’s cancers at the American Cancer Society in Atlanta. For now, she says, cervical cancer screening, beginning at age 21, is still necessary.
8. Protection Against Cervical Cancer Does Not Differ Among Blacks and Whites
The HPV vaccine is equally effective at preventing cervical cancer in white and black women, Drs. Saslow and Markowitz say. A study published in 2014 in the journal Cancer Causes & Control raised concerns that it might not work as well in black women. In the study, researchers found that black women diagnosed with precancerous cervical changes were two times less likely to be infected with strains of vaccine-preventable HPV (16 and 18) than white women. Other strains of HPV not covered by the available vaccine were more common in black women in the study. But, Markowitz explains, precancers caused by strains other than 16 and 18 are less likely to progress to cancer. In addition, Gardasil 9 now protects against all but three of the strains that were more common in black women in the study. Additional reporting by Ingrid Strauch.
