Drop in Prevalence of HPV Infection Seen With Just One Shot of HPV Vaccine

By Will Boggs MD

December 30, 2019

NEW YORK (Reuters Health) - Even a single dose of human papillomavirus (HPV) vaccine is associated with a reduced prevalence of HPV infection among U.S. women, according to findings from the National Health and Nutritional Examination Survey (NHANES).

"Getting adolescents to initiate their first dose should be a priority, with the goal that they will complete the recommended series," Dr. Ashish A. Deshmukh from UTHealth School of Public Health, in Houston, Texas, told Reuters Health by email. "Our findings are promising; however, they are not suggestive that only one dose is adequate until we get further definite answers from currently ongoing trials."

While about two-thirds of adolescents in the U.S. have received at least one dose of the HPV vaccine, only about half have completed the three-dose series.

Dr. Deshmukh's team used NHANES 2009 to 2016 data to investigate HPV-infection prevalence among U.S. women by the number of vaccine doses received.

Among the 1,620 women included in the study, 1,004 were unvaccinated, while 106 had received one dose, 126 had received two and 384 had received three.

The prevalence of infection with HPV type 6, 11, 16 or 18 was significantly lower among women who received one (2.4%), two (5.1%), or three doses (3.1%) of HPV vaccine than among unvaccinated women (12.5%), the researchers report in JAMA Network Open.

After adjustment for other factors, the predicted probability of infection with these HPV types remained significantly higher in unvaccinated women (7.4%) than in women who received one, two doses or three doses of the vaccine.

The predicted probability of infection with these HPV types was significantly greater among black women (10.8%) than among white women (6.6%) and among women with more than five lifetime male sexual partners (11.6%) than among women with fewer lifetime male partners (3.3%).

"If a single dose of HPV vaccine could provide protection for a long-enough duration similar to currently recommended 2 or 3 doses, then receipt of vaccine (i.e., just initiating the series) will be a more achievable metric of population coverage," Dr. Deshmukh said. "The implication of our findings will be greater in low-resource countries where cervical cancer still remains one of the leading causes of cancer mortality."

"Yet, the HPV-vaccination coverage is extremely poor, as getting adolescents to receive their first dose itself is a big hurdle, and in many countries, as generally, there is not adequate infrastructure to provide the recommended vaccine series," he said.

Dr. Deshmukh added, "Continued and effective physician recommendation has a great potential to overcome the existing hurdles, mainly parental indecisions about both vaccine initiation and completion."

Dr. Margaret Stanley of the University of Cambridge, in the UK, who has researched various aspects of HPV infection, told Reuters Health by email, "These observations should be placed in context with other studies, but my view is that the available evidence is that immunization with 1 dose of HPV vaccine at high coverage in >80% in sexually naïve adolescents is protective against vaccine-type persistent HPV infection for at least 10 years. However, for policy changes and implementation of a 1-dose schedule, evidence from randomized controlled trials will be necessary."

"The name of the game is to get HPV vaccine into as many 9- to 15-year-old boys and girls as possible, even if it's only one dose," she said.

SOURCE: https://bit.ly/363fAlo JAMA Network Open, online December 27, 2019.