Measles Outbreak in Ontario: Continued Vigilance Needed to Prevent Spread

As the spread of measles in Ontario has largely subsided, Public Health Ontario (PHO) emphasizes the importance of continued vigilance to prevent the disease from continuing to spread. With students returning to school, PHO advises families to ensure children are up to date on their measles vaccinations. The current outbreak has highlighted the need for all Ontarians to be vaccinated against measles, with individuals aged 19 and younger representing 73.1 per cent of cases.

Key Takeaways:

• As of Aug. 19, there were 2,363 measles cases reported in Ontario in connection with a multi-jurisdictional outbreak declared on Oct. 18, 2024.
• Individuals aged 19 and younger represented 73.1 per cent of all cases, and approximately 96 per cent of them were individuals who were not immunized against measles.
• Measles vaccines are safe and effective, preventing illness, severe illness, hospitalization, and death, and helping interrupt chains of transmission.
• The first dose of the measles vaccine is given as part of the measles, mumps and rubella (MMR) vaccine at age one, and the second dose is given as part of the measles, mumps, rubella and varicella (MMRV) vaccine at four to six years old.
• Children under four can receive an early second dose in some areas, such as in public health units where the outbreak vaccine strategy is in place.
• People who have not had measles or have not been vaccinated against measles are at greatest risk of infection, including infants (under 12 months), pregnant people, and immunocompromised individuals.
• Measles is a highly contagious virus that lives in the nose and throat mucus of an infected person, spreading easily through the air or on surfaces and causing serious health issues if left un vaccinated.

Statistics:

• 2,363 measles cases reported in Ontario as of Aug. 19, 2024.
• 73.1 per cent of cases were individuals aged 19 and younger.
• 96 per cent of individuals under 19 were not immunized against measles.
• Measles vaccines are 97 per cent effective in preventing measles.
• Measles can cause pneumonia, ear infections, diarrhea, hearing and vision loss, respiratory failure, brain swelling (encephalitis), seizures, and death in severe cases.
• Canada is at risk of losing its measles elimination status if the outbreak continues uninterrupted past Oct. 27, 2024.

Sources:

• Public Health Ontario (PHO)
• Ontario Ministry of Health
• Public Health Agency of Canada
• World Health Organization (WHO)
• Pan American Health Organization (PAHO)