TORONTO — Canada’s health regulator said Friday that it is launching an expanded Canadian study of cervical cancer vaccine CoVID-19 that aims to provide a “full range of results” before making the vaccine mandatory for young girls.
The federal government earlier this month said it would not make the vaccine mandatory in Ontario, a move likely to keep infection rates under control. Immunization rates in this province have been consistently high and far exceed Canada-wide levels, according to a report issued last year by the province’s Centre for Disease Control.
The vaccine has proven effective in both preventing invasive human papillomavirus infection and in reducing the chance of developing cervical cancer. The vaccine, which had been recommended by the World Health Organization and is the first to block HPV types that cause most cervical cancers, was given to girls from age 9 to 12.
The WHO has said it “will continue to encourage all countries to expand the routine vaccination schedule” and that such moves could prevent 8 million new cervical cancer cases worldwide by 2030.
The Canadian study — the first of its kind since the vaccine was first recommended to be given to all girls as young as nine — is needed to “assess the relevance of the HPV vaccines and their safety to adolescent girls and their parents,” according to Dr. Halina Malmgren, director of the division of HPV vaccine at Public Health Ontario, a state-run agency that manages all aspects of health care in the province.
The agency said on Thursday that HPV-19 and CoVID-6, two other HPV-preventative vaccines, are now available in all Ontario public health care institutions.
While recent data from Canada suggests that the number of HPV infections among girls ages 11 to 14 has declined significantly, so has vaccine efficacy, according to a 2017 report from Public Health Ontario. These numbers, combined with research studies, underscore the need for better long-term data to determine which types of HPV are responsible for most cervical cancer.
There are around 750 cases of cervical cancer diagnosed in Canada each year, with more than 40 percent of patients over 50, according to the agency. About 60 percent of the cases are linked to infections with HPV types 16 and 18, according to Public Health Ontario.
The clinical data, according to Health Canada, show that more than 20 percent of girls who received CoVID-19 have shown reduced levels of HPV infection, which is considered a good long-term measure.
The vaccine is required in Canada, but no Canadian province has required the immunization to be given to all girls by age 13.
Advocates for the vaccine say requiring the shots in school will help prevent new infections, lower infection rates and could change the pattern of sexually transmitted infections among young people.
Although vaccinating girls up to age 19 would still spare them several months of school-based immunization, it would allow the vaccine’s greatest benefits to be felt much earlier, before girls become sexually active, advocates say. Many schools have already started to mandate the immunization, but public health agencies said the number of schools that offer the vaccine for all grade levels is still far less than half.
The Federal Ministry of Health said it would work with the provinces to consider whether increasing the minimum age for mandatory vaccination among girls was “workable.” It also said that restrictions on use of the vaccine had been met successfully in 11 other countries, including India, Brazil and Thailand.