HPV vaccines work: new data from Public Health England show that the vaccine has led to a significant decline in the number of young women infected with the virus in the UK.

HPV Vaccination in Sao Paulo, Brazil.
Image via Pan American Health Organization PAHO / Flickr.

Between 2010 and 2016, infections with human papillomavirus (HPV) strains 16 and 18 fell by 86% in women aged 16 to 21 who were eligible for the vaccine. HPV 16 and 18 are the two strains responsible for most cervical cancer cases associated with the virus. Overall, the HPV vaccination program introduced in 2008 led to a sharp decline in the five high-risk strains of HPV — which collectively cause 90% of cervical cancer cases — a new study reveals.

Safely inoculated

“The study shows the positive effects of HPV vaccinations,” said David Mesher, lead author of the study. “There have been some very positive results from the program.”

The study also identified a decline in several strains of HPV that are not covered by the vaccine — suggesting that the treatment can help inoculate against various strains.

The study worked with a sample of 15,349 English women aged 16 to 24 who visited a doctor’s office for chlamydia screening between 2010 and 2016. Along the reduction in HPV infection rates, the team also reports a decline in diagnoses of genital warts among boys and girls aged 15 to 17 between 2009 and 2017. These are caused by certain HPV strains that the vaccine is meant to protect against.

HPV spreads from infected individuals through sexual contact. The US Centers for Disease Control and Prevention says that “almost every person who is sexually-active will get HPV at some time in their life if they don’t get the HPV vaccine”. For women, it can be especially dangerous, as HPV infections can develop into cervical cancer, the fourth most common cancer in women globally. “Virtually all cervical cancer cases (99%) are linked to genital infection with HPV which is the most common viral infection of the reproductive tract,” writes the World Health Organization (WHO).

There are over 100 known strains of HPV out there, and the vaccine doesn’t protect against all of them. But it does protect against the most dangerous ones. The vaccine is typically administered to girls aged 12 to 13 since that’s when it’s most effective. The UK has achieved an impressive 80% vaccination rate for women between the ages of 15 and 24. According to Masher, the results show that the HPV vaccine “works better than anybody would have expected”.

Some 80 million people have been vaccinated against HPV globally, the team notes. While vaccination rates have increased during the last 10 years, even in some of the world’s more affluent countries, such as the U.S., France, Denmark, and Japan, vaccination levels are low. The UK’s efforts are inspiring other countries to establish vaccination drives.

The paper “The Impact of the National HPV Vaccination Program in England Using the Bivalent HPV Vaccine: Surveillance of Type-Specific HPV in Young Females, 2010–2016” has been published in The Journal of Infectious Diseases.