Tips & Resources

A New Generation of Measles

By the Intrepid 24/7 Content Team

Measles is a condition that is most commonly associated with small children. However, in early 2015, there was an increase in cases among adults—some of whom had been vaccinated. How did measles make its way back into the North American population, and why are so many adults becoming infected? We explain the cause and effect of this highly contagious virus that has re-entered Canadian communities in a matter of weeks.

In January, headlines were made when an outbreak of measles hit the United States, with 102 new cases (mostly children) across 14 states. These were linked to a cluster of cases in Disneyland as the starting point. Immediate attention was placed on the anti-vaccination movement, which has gained momentum over the past decade as more parents are choosing not to vaccinate their children with the MMR vaccine (which covers measles, mumps, and rubella). This movement stemmed from the belief that the MMR vaccine was causing autism, and since measles had been practically non-existent in North America for the past ten years, these parents believed there was no need to inject their child with these vaccinations.

In parallel with this belief was the beginning of the “freedom movement,” in which parents rejected government control and believed they should be making their own decisions for their children. As a result, many parents made the choice not to inoculate their children with the MMR vaccine.

In February 2015, cases of measles started popping up in Toronto, with a surprising number of adults infected—including adults who had been vaccinated. The count now sits at six cases, with four of them being adults. The MMR vaccine was implemented in the early 1960s, and coverage hit a peak in the mid-1980s. By the late 1990s it was believed that measles was close to local extinction in North America, but all it took was one infected visitor or one non-vaccinated child to bring the virus back from near eradication.

As seen in the Toronto outbreak, not all adults who were vaccinated remain safe. In late 2014, there was an outbreak of mumps (which falls into the MMR grouping) in the NHL, including all-star player Sidney Crosby and some of his teammates from the Pittsburgh Penguins. How did this happen? There’s a lot of speculation that people born between 1970 and 1992 (Crosby and the majority of his teammates were born within this period) are only partially protected against MMR diseases. This is because at that time, children were only administered one dose of the vaccine instead of the two that children receive today, which is now known to confer more immunity against these diseases.

It’s believed that the outbreak in Toronto is the result of the same situation. This vaccine gap in adults could potentially account for many thousands of Canadians who fall within this range and may be exposed to the virus.

What can adults do to protect themselves from measles?

The Public Health Agency of Canada says adults at greater risk of measles or mumps should get two doses of the MMR vaccine, the second one four weeks after the first. This includes adults who:

  • Have been exposed to measles or mumps or live in an area where an outbreak has happened
  • Are students in colleges or trade schools
  • Travel internationally
  • Work in health care

The Public Health Agency of Canada advises that adults with the following conditions should not receive the vaccine:

  • Pregnancy
  • Life-threatening allergic reactions to gelatin, a previous MMR vaccine, or a medication called neomycin
  • Serious medical conditions