What Next?
In Canada, the HPV vaccine is authorized for patients aged 9-45 years. Current immunization coverage among adolescents and young adults varies across provinces and falls below the national target of 90%. In its July 2024 update, NACI estimated that 76% of 14-year-olds of both genders received at least one vaccine dose and that 67% received two doses in 2023. Vaccine uptake was slightly higher among girls than boys.
To boost the coverage rate, shifting to a one-dose schedule could appeal to young people, as well as maintain vaccination efficacy.
“When you look at the studies that have been published worldwide, the effectiveness of one dose of the HPV vaccine is actually quite high,” said Caroline Quach-Thanh, MD, professor of microbiology, infectious diseases, immunology, and pediatrics at the University of Montreal, Quebec, Canada.
Quach-Thanh, who wasn’t involved with this study, previously served as NACI chair and now serves as chair of the Quebec Immunization Committee.
“In terms of prevention of HPV infections that may lead to cancer, whether you give one dose or two doses basically gives you the same amount of protection,” she said.
However, not all physicians agree about the switch in vaccination approaches. In early October, the Federation of Medical Women of Canada released a report with 12 recommendations to increase HPV vaccination rates, including a call for healthcare providers to continue with multidose immunization schedules for now.
“Vaccination is the most powerful action we can take in preventing HPV-related cancers. Canada is falling behind, but we can get back on track if we act quickly,” said Vivien Brown, MD, chair of the group’s HPV Immunization Task Force, chair and cofounder of HPV Prevention Week in Canada, and a past president of the federation.
After the NACI update in July, the task force evaluated the risks and benefits of a single-dose vaccine regimen, she said. They concluded that a multidose schedule should continue at this time because of its proven effectiveness.
“Until more research on the efficacy of a single-dose schedule becomes available, healthcare providers and public health agencies should continue to offer patients a multidose schedule,” said Brown. “This is the only way to ensure individuals are protected against HPV infection and cancer over the long term.”
The study was supported by the Public Health Agency of Canada, the Canadian Institutes of Health Research, the Bill & Melinda Gates Foundation, and Canadian Immunization Research Network. Sauvageau, Quach-Thanh, and Brown declared no relevant financial disclosures.
A version of this article first appeared on Medscape.com.