With rising measles infection and death rates abroad, medical experts warn that declining vaccination rates increase the risks of the virus returning to Canada.

Recently released international data from the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) show that in 2022, global measles infection rates rose by 18 percent compared to the previous year, with deaths attributed to the disease. There was a 43 percent increase at that time, and 37 different countries reported significant or devastating outbreaks.

During the latest update in August of last year, the Canadian government currently maintains a global health notice for measles, warning potential travelers of the increasing risk of disease outbreaks worldwide and encouraging them to ensure their protection against infection well before leaving Canada.

Locally, the measles virus has not been frequently encountered and has been closely monitored for years, with only 12 cases nationwide in all of 2023, according to the Public Health Agency of Canada (PHAC). However, amidst concerns about declining vaccination rates in Canada during the COVID-19 pandemic, the risks of measles returning — another potentially life-threatening virus — have increased.

Dr. Joan Robinson, a pediatric infectious disease specialist at Stollery Children’s Hospital in Edmonton, told CTVNews.ca in an interview: “So far, we have been lucky in Canada.”

"I think there are many reasons to believe the likelihood is very strong that we will begin to see more outbreaks within the next five years."

Measles usually causes a rash, fever, cough, and runny nose, and is more common in North America among the young. In rare and severe cases, complications from the infection can lead to respiratory failure and encephalitis, which in turn may cause hearing and vision loss, as well as nerve damage. Among pregnant patients, measles can also increase the risks of miscarriage, premature birth, and low birth weight, according to the Primary Health Care Center.

Some of the more severe effects of measles infection may also take years to develop, including subacute sclerosing panencephalitis, a rare and fatal disease affecting the nervous system that can appear as late as a decade after the initial infection.

One of the virus’s hallmark features is its contagiousness, as estimates from the CDC indicate that without protection, nearly nine out of ten people exposed to the measles virus will become infected. To achieve herd immunity, WHO guidelines suggest that 95 percent or more of individuals should receive full vaccination.

As Robinson described, without this level of immunity, outbreaks can easily spiral out of control.

She said: "If measles is introduced into the classroom... within weeks, there could be widespread transmission." "Another problem is that unvaccinated children tend to cluster together… and you certainly have pockets where vaccination rates are very low."