Measles outbreaks feared as vaccination rates plummet
Children at risk, with only 75 per cent of students immunized at some schools
Vaccination rates against measles have dropped to as low as 75 per cent at some Montreal schools — a worrisome situation that risks leading to possible outbreaks in the future, a Montreal public health department official warned on Friday.
The warning comes as authorities confirmed Wednesday they detected a new case of measles in an unvaccinated child who recently returned from Africa. Public health investigators responded by tracing the child's contacts at school and elsewhere, seeking to reach anyone who may have come near the individual when they were contagious from Jan. 26 to Feb. 6.
Montreal last declared a community measles outbreak in May 2019, when officials discovered that at least a couple of individuals had contracted measles in the city and not abroad.
The World Health Organization observed a 30-fold rise of measles cases last year in Europe, including 21,000 hospitalizations and five measles-related deaths amid a “backsliding in vaccination coverage from 2020 to 2022.” Meanwhile, the U.S. Centers for Disease Control issued an emergency warning on Jan. 25, advising the public to remain vigilant after 23 cases were confirmed in several states from Dec. 1 to Jan. 23.
The U.S. cases included “seven direct importations of measles by international travellers and two outbreaks with more than five cases each. Most of these cases were among children and adolescents who had not received a measles-containing vaccine ... even if age-eligible,” the CDC stated.
Dr. Paul Le Guerrier, in charge of the immunization team at the Montreal public health department, noted that community vaccine coverage against measles should be at least 95 per cent to prevent local transmission of the highly infectious virus. He estimated Montreal's vaccination rate to range between 80 and 88 per cent, but in some schools the coverage is now as low as 75 per cent.
“The problem that we're seeing is that more and more countries are reporting outbreaks — whether it's in the States, or in Europe, Africa and Asia,” Le Guerrier said. “There are many outbreaks abroad and since many Canadians travel, there's a greater risk that unprotected Canadians get infected while they're travelling, and they come back with the disease and then spread it to people who are not adequately protected here in Montreal.”
Beyond the telltale red spots and rash of the measles, the illness can cause severe complications in children and adults. About one in five unvaccinated people in the U.S. who get the measles is hospitalized, according to the CDC. Up to three out of every 1,000 children who become infected with measles will die from respiratory and neurological complications.
Two doses of a measles vaccine after one year of age is almost 100 per cent effective at preventing the disease. There are two kinds of measles-containing vaccines in Canada: the measles-mumps-rubella (MMR) shot and the measles-mumps-rubella-varicella (MMRV) vaccine. The first dose is usually given to children when they're between 12 and 15 months old, and the second to children at 18 months of age or before they enter school.
But people can still get vaccinated against measles at later ages, including as adults. Le Guerrier advised Canadians who have not been vaccinated against measles to get their shots before travelling abroad.
Vaccination rates against measles started dropping around the world after a U.K. gastroenterologist, Andrew Wakefield, produced a now-discredited study in 1998 that purported to show a link between the MMR vaccine and autism.
Le Guerrier suggested other reasons for vaccine hesitancy in Montreal.
“We do have a large ethno-cultural population with many different languages, and so parents perhaps don't quite understand the importance of vaccination,” he explained. “Or they have so many other problems to deal with that when the school sends a vaccination letter — even if it's translated, and we do translate the letters into 12 languages in Montreal — they still don't get their kids vaccinated.”