Do I need a third dose of the measles vaccine? And other common questions answered

Measles Outbreak in Canada: What You Need to Know

The year 2025 has already proven to be a challenging one for Canada, with a resurgence of measles cases. This is particularly alarming as the disease was declared eliminated in the country back in 1998. Ontario is currently the epicenter of the spread, with Public Health Ontario reporting 1,018 confirmed and probable cases of measles so far this year. The majority of those affected were not fully immunized, leading to six unvaccinated children and adolescents being hospitalized due to the virus.

Alberta is also facing a similar situation, with 129 reported cases by April 24 across all zones in the province. Like in Ontario, most of the affected individuals in Alberta are not fully vaccinated, resulting in nine hospitalizations.

Measles is highly contagious and can manifest with symptoms such as fever, coughing, a runny nose, and a red rash. In severe cases, measles can lead to complications like brain inflammation, pneumonia, and even death.

As the virus continues to spread, questions about immunity to measles have arisen. Can measles immunity wane over time? Immunologist Dawn Bowdish explains that two doses of the measles, mumps, and rubella (MMR) or measles, mumps, rubella, and varicella vaccine (MMRV) offer nearly 100% effectiveness in the long term. However, there is a small percentage of individuals who may experience a decrease in immunity, leading to breakthrough infections. Despite this, those who have received two doses of the vaccine are still significantly protected, albeit not completely immune.

To check whether you are protected against measles, a blood test can be conducted to detect antibodies against the virus. This is particularly important for pregnant women and those planning to start a family, as measles can pose serious risks during pregnancy. If unsure of vaccination status, it is recommended to receive another dose of the vaccine rather than opting for a blood test.

Do you need a third dose of the measles vaccine? Canadian public health authorities do not recommend a third dose for the general public at this time, as resources are prioritized for unvaccinated individuals. Exceptions may apply for those on immunosuppressive medications or undergoing cancer treatments, but such decisions should be made in consultation with a healthcare provider.

In conclusion, staying informed about measles immunity and vaccination status is crucial in the face of this ongoing outbreak. By taking proactive measures and following public health guidelines, we can work together to contain the spread of measles in Canada.