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Oral HPV infection rates are now 37 per cent lower among unvaccinated US men, suggesting the widespread rollout of the HPV vaccine has led to herd immunity.

In the US, vaccinations to protect against the most common types of HPV were first officially recommended for girls in 2006 and for boys in 2011. In addition to causing most cervical cancer, HPV is also linked to some types of mouth and throat cancers.

Despite this, little research has been done on the effects of the vaccine on oral cancers, so Anil Chaturvedi at the National Cancer Institute in the US and his colleagues looked at a nationwide survey on HPV infections in the years following the vaccines’ introduction.


Almost 14,000 adults took part in the survey, conducted from between 2009 and 2016. Over those years, HPV vaccination rates increased from zero to 5.8 per cent in men and from 7.3 per cent to 15.1 per cent in women.

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During this period, the prevalence of the types of HPV included in the vaccines dropped from 2.7 per cent to 1.6 per cent in men who had not been vaccinated. This represented a 37 per cent drop among the unvaccinated adult men.

This suggested herd immunity was protecting these men, the team wrote. “Herd protection likely arises from increased levels of female HPV vaccination in the US population.”

Chaturvedi and his colleagues failed to find a similar protective effect among unvaccinated women in their study. This could be explained by a low prevalence of oral HPV in the women included, they wrote.

There are more than 100 different types of HPV, and the current vaccines only protect against the most common and harmful types. The number of men infected with HPV types that were not included in the vaccine remained the same over the study period.

Journal reference: JAMA, DOI: 10.1001/jama.2019.10508