Just one dose of the HPV vaccine needed, according to WHO

The World Health Organisation has found that people only need one dose of the human papillomavirus (HPV) vaccine to be protected from the virus.

This means that more people can be vaccinated against the virus, which causes 95% of cervical cancers worldwide.

The previous recommended regime for the HPV vaccine is two doses for girls aged 9-14, or three doses for young women aged 15-20. But based on an evaluation of the evidence, the WHO’s Strategic Advisory Group of Experts on Immunisation (SAGE) has found that one dose is comparable to two and three in both of these groups.

SAGE now recommends just one or two doses for women from age 9 to 20, but two doses with a six-month interval for women 21 and older. Immunocompromised people should still have three doses if possible.

The 9-14 age group remains the main target for vaccination, and the recommended age to get a shot. This is because it makes it likely that girls will be immunised before being exposed to the sexually transmitted HPV.

“The HPV vaccine is highly effective for the prevention of HPV serotypes 16 and 18, which cause 70% of cervical cancer,” says Dr Alejandro Cravioto, the chair of SAGE. The vaccine also helps to prevent other types of HPV.

“SAGE urges all countries to introduce HPV vaccines and prioritise multi-age cohort catch-up of missed and older cohorts of girls,” says Cravioto.

“These recommendations will enable more girls and women to be vaccinated, thus preventing them from having cervical cancer and all its consequences over the course of their lifetimes.”

The WHO has a strategy, released in 2020, to “eliminate” cervical cancer worldwide. (Elimination here means fewer than four cervical cancer cases per 100,000 women, as there will still be some rare cervical cancer that isn’t caused by HPV or detectable in screening.)

Vaccination is a key part of this strategy, with a 2030 target of 90% of girls being immunised against HPV by age 15. In 2020, only 13% of girls were fully vaccinated against HPV.

Professor Julia Brotherton, medical director of population health at the Australian Centre for the Prevention of Cervical Cancer, and a researcher at the University of Melbourne, calls the updated WHO recommendation a “major development in the fight towards ending this devastating disease for women across the world”.

“Only needing one dose makes HPV vaccine programs easier to deliver, cheaper and more acceptable, and can ensure the available HPV vaccine supply reaches girls in countries who need it most,” says Brotherton.

Australia is aiming to eliminate cervical cancer by 2028. Currently, the Australian Technical Advisory Group on Immunisation (ATAGI) recommends two doses of the HPV vaccine for all children (including boys) at ages 12-13. This is available for free through school immunisation programs.

“It will be up to ATAGI now to consider the evidence that informed the SAGE recommendation and whether to recommend that Australia should alter its current schedule,” says Brotherton.

Some countries, such as the UK, have already suggested they’re planning to move to a one-dose recommendation.

The HPV vaccine, also called Gardasil-9, was co-developed by Australian researchers in the 1990s. It contains a range of proteins from different human papillomaviruses, but not whole viruses. (Production of the Novavax COVID-19 vaccine is based on a similar idea.)