ATLANTA-Although human papillomavirus (HPV) infection is associated with elevated risk of certain cancers, individuals with risk factors for contracting HIV have lower vaccination rates than the general public, according findings presented at the annual meeting of the American Association for Cancer Research (Abstract 3327).
Persons with compromised immunity as a result of HIV may not be able to ward off HPV infection, and therefore could be more prone to developing anal and cervical cancer, explained Lisa T. Wigfall, PhD, Assistant Professor at the College of Education and Human Development at Texas A&M University in College Station.
HPV vaccines have been available since 2006 against strains most likely to cause anal and cervical cancer, but vaccination rates remain far below the national goal of 80 percent, she told a press briefing.
As of 2017, about 49 percent of U.S. adolescents were up-to-date on HPV vaccination, and 66 percent had received their first dose, according to the CDC. Current CDC guidelines recommend adolescent boys and girls up to 15 years of age receive two doses of the vaccine starting at age 11 or 12. Those vaccinated after that should receive three doses, according to the agency.
Wigfall and her colleagues examined survey data from the 2016 Behavioral Risk Factor Surveillance System (BRFSS) to assess HPV vaccination rates in individuals who reported engaging in one or more high-risk behaviors in the year before. Out of 486,303 adults, 3.39 percent had used injection drugs and/or engaged in high-risk sexual behavior and, of these, very few were fully vaccinated against HPV.
The team found that HPV vaccination rates were far lower among non-Hispanic black individuals than for any other racial or ethnic group.
"It was alarming that almost all non-Hispanic blacks in the study were unvaccinated, especially given the disproportionate burden of HIV/AIDS among this minority group," Wigfall said.
"Gender and sexual orientation are important topics that should not preclude us from identifying and targeting HPV vaccination efforts among high-risk populations," Wigfall noted, adding that patient-provider vaccine communication should be strengthened for high-risk populations, especially HIV-positive individuals and HIV-negative gay/bisexual men and transgender individuals.
One possible explanation for low vaccination rates in these latter individuals could be that recommendations for people living with HIV came out several years after the HPV vaccine became available. Another factor could be that for some high-risk populations, such as gay/bisexual men or transgender individuals, health providers may not have addressed connections between high-risk sexual behaviors and HIV/HPV co-infection, she explained.
"A necessary first step would be the wide adoption of routine HIV testing for all adolescents and adults, regardless of perceived risk," Wigfall said, noting that the CDC has recommended routine HIV testing since 2006. That recommendation has not been widely followed, leaving thousands of people living with HIV unaware of their HIV-positive status, according to Wigfall.
Although the study was funded by the NCI, she emphasized that her opinions are hers and not the agency's.
Methodology
The researchers used BRFSS data to assess HPV vaccination rates among 486,303 adults between the ages of 18 and 36 years. They found that 3.39 percent of those surveyed reported having used injection drugs and/or engaged in high-risk sexual behaviors, and HPV vaccination rates varied between these high-risk individuals.
Among gay/bisexual males, 31.9 percent reported having initiated the HPV vaccine series, but just 6.2 percent had completed three inoculations. However, among 16,507 gay/bisexual males, only 2.52 percent had complete data for all variables.
Among high-risk heterosexual males between the ages of 18 and 29 years, just under 11 percent had begun the series, while 25.6 percent of high-risk heterosexual females ages 18-36 years had completed the three-vaccine series, while 10.91 percent of heterosexual males aged 18-29 years had initiated the series.
Racial/ethnic differences in vaccination rates were not statistically significant, except among non-Hispanic blacks. Rates for both HPV vaccine initiation (11.91%) and completion (15.72%) were higher for high-risk adults who had been tested for HIV, but the differences were not statistically significant.
"It was alarming that HPV vaccination rates were low among HIV infection high-risk adults in our study, including gay/bisexual males who have the highest HPV-associated cancer risk," said Wigfall.
"For example, anal cancer risk among gay/bisexual males is exacerbated by HIV/HPV co-infection. Additionally, it was also alarming that almost all non-Hispanic blacks were unvaccinated, especially given the disproportionate burden of HIV/AIDS among this racial/ethnic minority group. It is essential that increasing HPV vaccination rates among unvaccinated HIV infection high-risk adults remain a public health priority."
Commentary
"Cancer prevention vaccines are built on tremendous basic and translation science," noted Kimlin Tam Ashing, PhD, Professor of Population Sciences at City of Hope Medical Center in Duarte, Calif. "Now it will take behavioral science to increase uptake to achieve the full promise to these vaccines-in particular the HPV vaccine to eradicate HPV-related cancers."
Oncologists have a role to play in getting the word out, she told Oncology Times.
"There is a lack of recognition that pediatric and adult cancer patients are immune-compromised. Oncologists, therefore, have the opportunity to improve protection from HPV-related cancers via HPV vaccination. Further, the safe and effective HPV vaccine is now FDA-approved for adults up to age 45. This affords clinicians the responsibility and opportunity to prevent HPV infection and HPV-related cancers among immune-compromised and non-immuno-comprised adults."
Together with research led by the African Caribbean Consortium- formed in 2006 to study viral, genetic, environmental, and lifestyle risk factors for cancer in populations of African descent-the study may stimulate advocacy engagement about cancer prevention vaccines and help increase community vaccination, she added.
"Given the FDA approval of the HPV vaccine for adults up to age 45, we now need more research, including behavioral studies on acceptability and uptake for both clinicians and patients as well as immunogenicity studies involving immune-compromised patients, including cancer survivors."
Kurt Samson is a contributing writer.