HPV vaccine uptake disappointing despite proven efficacy
Human papillomavirus (HPV) vaccination demonstrates efficacy against oral HPV infections among young adults, although the low uptake limits the population-level effectiveness of the vaccine, according to a cross-sectional study presented at the 2017 ASCO Annual Meeting in Chicago.
In a cohort of 2,627 men and women aged 18 to 33 years participating in the National Health and Examination Survey (2011 to 2014), only 18.3 percent reported receipt of at least one dose of the HPV vaccine before 26 years of age. Furthermore, the vaccination rate was significantly lower among men than women (6.9 vs 29.2; p<0.001). [ASCO 2017, abstract 6003]
Among vaccinated individuals, the (population-weighted) prevalence of oral HPV infections covered by a quadrivalent vaccine (types 16, 18, 6 and 11) was lower as compared with those who did not receive the vaccine (0.11 vs 1.61 percent; p=0.008). The estimated reduction in prevalence was 88.2 percent (95 percent CI, 5.7 to 98.5).
Similarly, men who received the vaccine had significantly reduced oral HPV16/18/6/11 prevalence compared with unvaccinated men (0.0 vs 2.13 percent; p=0.007). On the other hand, there was no significant difference in the prevalence for 33 nonvaccine HPV types (3.98 vs 4.74 percent; p=0.24).
Taking into account the vaccine uptake, the estimated population-level impact of HPV vaccination on the burden of oral HPV16/18/6/11 infections was modest, driving the prevalence down by 17 percent overall (25 percent in women and 6.9 percent in men).
“Rates of HPV-caused oral cancers continue to rise every year in the US, particularly among men. And yet, no clinical trial has evaluated the potential use of the HPV vaccine for the prevention of oral HPV infections that could lead to cancer,” said senior study author Dr Maura L. Gillison from the University of Texas MD Anderson Cancer Center.
“While we were encouraged that there was a notable impact of the vaccine on oral HPV infections among vaccinated individuals, that benefit was modest overall and lower than we would hope in men due to low vaccine uptake,” Gillison added.
She pointed out that the HPV vaccine is one of the most important advances in cancer prevention in the last several decades, and parents who decide to have their children vaccinated against HPV should know that the vaccine may confer other beneficial effects, such as prevention of oral HPV infections linked to oral cancers.
Additional studies are warranted to investigate whether the vaccines could eventually reduce the rising incidence of oral cancers associated with oral HPV infection, she said.Commenting on the present study, ASCO President-Elect Dr Bruce E. Johnson said, “The hope is that vaccination will also curb rising rates of HPV-related oral and genital cancers, which are hard to treat. This study confirms that the HPV vaccine can prevent oral HPV infections, but we know it only works if it’s used.”