Core Viewpoint - The resurgence of measles in Canada, with over 5000 reported cases this year, has raised significant public health concerns, particularly due to the role of unvaccinated individuals in the outbreak [1] Summary by Relevant Sections Measles Outbreak Data - As of September 20, Canada has reported 5006 cases of measles this year, with Alberta and Ontario being the most affected provinces [1] - A premature infant infected with measles in utero has died, marking a severe consequence of the outbreak [1] Vaccination and Public Health Response - Health officials attribute the large-scale outbreak primarily to unvaccinated individuals, highlighting the importance of vaccination [1] - Experts recommend that individuals planning to become pregnant complete the measles, mumps, and rubella (MMR) vaccination prior to conception [1] Nature of Measles - Measles is an acute respiratory infectious disease caused by the measles virus, primarily transmitted through respiratory droplets and aerosols [1] - Symptoms typically appear one to two weeks after exposure and can include high fever, cough, runny nose, red eyes, and rash, with severe cases potentially leading to pneumonia and death [1]

Group 1 - A baby infected with measles has died in Ontario, Canada, marking the first reported death from measles in a child this year [1] - The deceased was a premature infant who contracted the virus from an unvaccinated mother [1] - Measles is a highly contagious respiratory disease that can lead to severe complications, including pneumonia and death [1] Group 2 - Ontario is experiencing a significant outbreak of measles, with 1,729 confirmed cases and 280 suspected cases reported from October 28, 2024, to June 3, 2025 [2] - The outbreak is linked to a larger epidemic that began in New Brunswick and primarily affects unvaccinated individuals [2] - The United States is also facing a measles outbreak, with 1,088 confirmed cases reported this year, the highest in six years [2] Group 3 - Public health officials are urging vaccination as the best preventive measure against measles, emphasizing the risks for unvaccinated individuals [3]