One HPV vaccine dose often sufficient, say WHO advisers

A single dose of the human papillomavirus (HPV) vaccine is now deemed the most efficient immunization strategy for cervical cancer prevention, according to the World Health Organization’s (WHO’s) Strategic Advisory Group of Experts on Immunization (SAGE).

A persistent HPV infection can lead to multiple types of cancers, including cervical cancer, which is the fifth most diagnosed cancer among women, according to the WHO. Vaccination, however, prevents 90% of these cancers from developing. 

Based on new evidence, SAGE recommends that just one dose of the HPV vaccine is typically enough. The advisory group recommends girls aged 9 to 14 years old get the vaccination—though countries may consider administering it to girls as young as age 4, if it’s likely to increase coverage. 

Also, the single-dose schedule can be extended to people who have yet to be vaccinated: Women who are 25 years of age or younger should be prioritized, followed by women up to 30 years, then boys from 9 through 14 years, and finally males up to 20 years of age.

SAGE says that people who are immunocompromised, including those with well-controlled HIV, should continue to receive two doses of the HPV vaccine. For those who are severely immunocompromised, it recommends three doses. 

The WHO last updated its HPV vaccine guidance in 2022, when it said a single dose was an acceptable “alternative schedule” to the two-dose regimen, based on a SAGE recommendation from April that year.

Policy not static, driven by evidence and public health needs

Funding shortfalls and human resource constraints are making evidence-driven vaccine policies “more critical than ever,” said Kate O’Brien, MD, director of the WHO’s department of immunization, vaccines and biologicals, during Tuesday’s press conference in Geneva. 

Currently, the global HPV vaccination rate is 33%, and O’Brien said the new recommendations can help the WHO meet its goal of 90%.

Moving to a single HPV dose aligns with the findings from an evidence brief from Johns Hopkins University, which cites multiple studies showing the high efficacy of this simplified regimen. 

“These cost savings could potentially stretch immunization budgets further, allowing countries to protect more girls against HPV and cervical cancer,” the brief notes. “Additional cost savings may be seen in reduced cold chain requirements, as fewer doses would require countries to purchase fewer refrigerators.” 

Vaccine policy is not static, said Annelies Wilder-Smith, PhD, SAGE’s executive secretary.

“As new evidence emerges, epidemiological patterns evolve, and public health needs change, and therefore our recommendations must evolve accordingly,” she said.

New mpox vaccine advice, as well

SAGE also released recommendations for the mpox vaccine, advising that immunization efforts during outbreaks of the virus should target children, people exposed to mpox through sexual networks, and those who have had contact with someone infected. Healthcare professionals and outbreak response workers should also receive it.

Preventive mpox vaccination can be considered for people at high risk for infection or severe disease, SAGE said. This includes people with advanced HIV or other immunocompromising conditions, laboratory personnel working with orthopoxviruses, and healthcare workers at risk of occupational exposure.