Canadian vaccination programs could switch to a 1-dose gender-neutral human papillomavirus (HPV) vaccination approach and eliminate cervical cancer, suggests new modelling in CMAJ (Canadian Medical Association Journal).

“Our results have important policy implications in Canada, and in other similar high-income countries evaluating whether to switch to 1-dose HPV vaccination,” writes Dr. Marc Brisson, a full professor at Laval University, Québec, and director of the Mathematical Modeling and Health Economics of Infectious Diseases Lab at the Centre de recherche du CHU de Québec–Université Laval.

Countries around the world are looking at whether to move from a 2-dose to 1-dose HPV vaccination approach after a 2022 recommendation by the World Health Organization Strategic Advisory Group of Experts on Immunization based on clinical trial evidence. Human papillomavirus can cause cervical cancer and other diseases.

Researchers in Ontario and Quebec modelled various scenarios based on 1- and 2-dose approaches to inform recommendations from the Canadian National Advisory Committee on Immunization and the Comité sur l’immunisation du Québec.

The group found that 1-dose gender-neutral vaccination could prevent a similar number of cervical cancers as 2 doses, if vaccine protection remains high during ages of peak sexual activity. “[A]ll 1-dose vaccination scenarios, even the most pessimistic, were projected to be a substantially more efficient use of vaccine doses than 2-dose vaccination; these scenarios were also all projected to lead to elimination of cervical cancer in Canada between 2032 and 2040,” write the authors.

This approach is a more efficient use of vaccine doses and is projected to help eliminate cervical cancer in Canada.

“The COVID-19 pandemic impacted HPV vaccination in Canada, particularly among vulnerable population subgroups. The potential economic savings by switching to 1-dose vaccination, and its programmatic flexibility, could allow investments to increase vaccination uptake in regions where coverage is suboptimal and in high HPV burden subgroups to mitigate the pandemic’s impact on programs and to reduce inequalities,” said Dr. Chantal Sauvageau, specialist in community health and consultant in infectious diseases at the National Institute of Public Health in the province of Quebec.

Regular monitoring of 1-dose protection is advised to detect signs of waning protection.

“Switching from a 2-dose to a 1-dose program of gender-neutral routine vaccination against human papillomavirus in Canada: a mathematical modelling analysis” is published October 7, 2024.