CDC: Prevalence of High-Risk HPV Rises in Unvaccinated Adults

High-risk oral and genital human papillomavirus (HPV) is apparently on the rise in the United States among unvaccinated adults, according to researchers at the Centers for Disease Control and Prevention (CDC).

A team of infectious disease specialists at the CDC has uncovered evidence suggesting that these infections have risen by more than 5% in adult women aged 18 to 59 who have not received the HPV vaccine. High-risk HPV infections are the types known to cause cervical cancer in women, and cancers of the penis in men.

The new report, released as a data brief from the National Center for Health Statistics, also revealed that while the prevalence of both high-risk oral and genital HPV is higher in unvaccinated men than women in all ethnic groups studied, that risk is significantly higher for high-risk oral HPV in men. High-risk oral HPV infections are linked to cancer of the oropharynx in both men and women.

The research team looked at data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, looking specifically at American adults who had not received the HPV vaccine. While 80 million Americans are currently infected with either oral or genital HPV, the virus is so common that the CDC had previously estimated that more than 90% of sexually active men and more than 80% of sexually active women will be infected with at least 1 of the approximately 200 types of HPV at some point in their lives, and that about 50% of those infections will be with 1 of about a dozen high-risk types that have been shown to cause cancer.

Among the findings from their review of the NHANES data, the authors, led by Geraldine McQuillan, PhD, found that from 2011 to 2014, the prevalence of any oral type of HPV was 7.3% for adults aged 18 to 69; of those infections, 4% were of one of the high-risk types.

In 2013 and 2014, the total prevalence of genital HPV in all adults aged 18 to 59 was 45.2% in men and 39.9% in women. Of these infections, 25.1% were high risk in men, and 20.4% were high risk in women. Previous data had estimated that the high-risk rate of HPV in women was 15.2%.

Among the entire population, non-Hispanic black adults had the highest rates of both oral (9.7%) and genital (64.1%) HPV of any type; non-Hispanic Asian adults had the lowest rates (2.9% and 23.8%, respectively). The same held true when the infections were broken down to high-risk types: non-Hispanic black adults had a prevalence of 4.3% compared with non-Hispanic Asian adults’ rate of 1.7% for high-risk oral HPV, and a prevalence of 33.7% compared with 11.9% for high-risk genital HPV.

Because these data were extrapolated from NHANES, the latest estimates do not include higher-risk populations, such as adults who are incarcerated, institutionalized, homeless, use injection-based illegal drugs, or are living in nonhospital-based long-term care facilities. Therefore, the CDC cautions that these estimates should be considered as a conservative look of both oral and genital HPV rates for all types.

A separate study by the CDC last year found that in women aged 14 to 19 who had received the HPV vaccine, the rate of infections had dropped by 64%. In vaccinated women aged 20 to 24, the rate dropped 34%, leading researchers to believe that as vaccine coverage increases, prevalence should drop across all population groups. That study was published in the March 2016 issue of Pediatrics.

The HPV vaccine became available in 2006 for girls and women aged 9 to 25 years, and received FDA approval in 2010 for boys and men aged 9 to 26 years. While the vaccines vary in how many types of HPV they protect against, all of the vaccines currently on the market protect against HPV 16 and 18, the two types known to cause the greatest risk of cervical cancer in women.

The vaccine is not effective in those who have already tested positive for the virus. The safety and efficacy of the vaccines in adults older than 26 years of age have not been studied, and therefore are not yet recommended in this population.

Details are in the CDC’s data brief.

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