What is measles?
Measles is the world’s most contagious human respiratory virus that spreads through the air indoors without needing to be close to someone who is infectious. It can quickly spread among people who are unvaccinated. For more information about symptoms and immunization visit our Measles FAQ page (www.hpepublichealth.ca/measles-faqs).
How is measles reported to South East Health Unit (SEHU) formerly Hastings Prince Edward Public Health)?
School principals are legally required to report suspected or confirmed cases of measles (and other diseases of public health significance) to the local health unit. If you learn that a student or staff has measles or is suspected of having measles, immediately notify SEHU by calling 613-966-5500, ext. 349 or 1-800-267-2803. If it is outside of office hours, please call the after-hours on-call system at 613-966-5500 and SEHU staff member will follow up with you as soon as possible. Public health also receives reports of suspected or confirmed diseases of public health significance, including measles, through other sources such as health-care providers, and will notify your school if an applicable case is reported. Public health will investigate the confirmed or suspected case and advise of necessary next steps.
What happens if there is an individual with measles at school?
When an individual with measles is reported at a school, the health unit quickly takes a thorough and proactive approach to the investigation to determine next steps.
The health unit’s first step is to check the school’s vaccination records using the provincial database. Any students or staff who cannot quickly show proof of measles immunity, either through full vaccination or a blood test showing natural immunity will be sent home and cannot return until the health unit confirms they are cleared. The priority is to temporarily exclude individuals and allow them back as they provide the necessary proof of immunity. The school principal or designate will be contacted for information to help inform the investigation (e.g. class lists, buses, attendance, etc.) and is required to support the exclusion of individuals that have not received all their vaccines and/or do not know their own measles immune status. If a case is identified in a school, school administrators and the school board should be prepared for significant disruption to programming given some staff will likely not be able to return to school quickly.
The health unit will work with the school principal and/or school board to ensure that students, families, and school staff are properly notified of any potential exposure. The purpose of timely notification is to provide important information and guidance for those who may have been exposed as well as excluded. We do not share specific information or details to protect privacy and prevent anyone from being identified.
IMPORTANT – School boards and schools are asked not to communicate information about measles to the school community without consulting public health. This helps to avoid unnecessary alarm, and ensure sharing of accurate information and guidance for protecting school community members.
For more information about the process for reporting and the investigation of diseases of public health significance, including measles, in schools, visit: Infection Control in Schools.
What will happen if there is a case or outbreak of measles in the community (exposures outside of school)?
When a case or outbreak of measles is confirmed, SEHU identifies potential contacts and contacts them directly to advise of their risk. If needed, SEHU releases information publicly to help people determine their risk of exposure and to provide them with guidance based on their unique circumstances.
If a school staff or student has been exposed to measles in the community, they should notify their school principal, as well as SEHU of their exposure. SEHU can be notified by calling 613-966-5500, ext. 349 or 1-800-267-2803. The advice received from public health will depend on factors such as their immunity/immunization status, if they have symptoms, and other personal health factors. Not everyone who is exposed to measles will be excluded from school. Students with an exemption on file, and students that do not have their MMR immunization up to date will be excluded until the outbreak is over and/or until their immunization is up to date.
What can school staff and families do to prevent measles?
The most important thing that school staff and families can do to prevent measles is to ensure their vaccinations are up to date. SEHU is urging individuals and families to ensure they are up to date with their measles vaccines and to remain watchful for symptoms, especially if not fully vaccinated. The following provides general measles immunity guidance; however, individuals should review their own personal records:
- Adults born before 1970 are generally assumed to acquired natural immunity to measles.
- Adults born after 1970 but before 1996 may only have one dose of the measles (MMR) vaccine and are encouraged to verify their immunization status. If only one dose has been received, a second dose is highly recommended.
- Adults and/or students born after 1996 are likely to have received two doses of the MMR vaccine and are considered immune to measles.
Under the Immunization of School Pupils Act (ISPA) parents/caregivers are responsible for reporting their student’s immunization status on measles, mumps, rubella, diphtheria, tetanus, polio, pertussis, meningitis, varicella (chickenpox) to public health. Immunizations can be reported online, by email at CDCIMM@hpeph.ca, or by calling 613-966-5500 or 1-800-267-2803, ext. 221. SEHU maintains a record of all reported immunizations, including measles vaccination, for all students, which can help to identify who may be at higher risk of infection if a case or outbreak of measles happens at school. Please note that SEHU does not have immunization records for anyone born in 1985 or earlier.
The MMR vaccine is publicly funded and available at your health-care provider’s office or through SEHU’s immunization clinics. Individuals whose immunization status for measles is not up to date can schedule an appointment with their health-care provider, or at hpePublicHealth.ca/clinic/immunization-clinic.
Public health continues to encourage all staff, students and families to monitor for symptoms of illness (fever, cough, running nose, red eyes, white spots in mouth, red blotchy rash) and stay home if they are unwell. If someone thinks they have measles, they should isolate immediately by staying home and avoiding contact with others. It is important that they get assessed by their health-care provider and call ahead before visiting a clinic or hospital so they can prepare for their arrival and prevent the virus from spreading. They should also wear a well-fitted mask when seeking medical assessment.
Will school staff be excluded from school if they have only one measles containing vaccine, or no record of vaccination?
All staff are encouraged to be aware of their immunization status, and obtain 2 vaccinations of measles containing vaccine. SEHU is responsible only for regular monitoring of the immunization status of students under the ISPA. If staff are susceptible, they will be excluded until the outbreak is over and/or until their immunization is up to date.
Who would be impacted if a case of measles is identified in a school (who is considered a close contact)?
A contact is anyone who shared a room or air space with a case for any length of time (and for two hours the case left the space) while the case was infectious. Depending on immunization or immunity status, individuals could be excluded from work, school, childcare and all public settings for up to 21 days after their last exposure to measles. Exclusion is an important way to protect individuals from infection and slow the spread of illness within schools; protecting the community, including those that are not fully immunized or cannot be vaccinated for medical reasons. Exclusion means individuals are not allowed to attend work, school, childcare or any public settings and must remain at home.
Due to the high effectiveness of the measles vaccine, most people who have received two doses of the MMR vaccine, are considered immune, and would not be excluded from school or childcare. It is generally assumed that adults born before 1970 were infected as children and have acquired natural immunity to measles.
What should someone do if they only have one MMR vaccination, or are unsure how many vaccinations they have:
If a patient’s immunization records are unavailable, immunization with Measles-containing vaccine is recommended.
Most individuals should be considered immune if they have received the standard two-dose vaccination schedule, unless there is uncertainty about their vaccination history or potential risk factors like pregnancy or severe immunosuppression.
Serologic testing is recommended for specific occupational groups, such as healthcare workers, who require either documentation of immunization or serologic proof of immunity regardless of their birth year. Serological testing might also be considered for: Pregnant women without documented MMR vaccination should be tested for rubella immunity; People with severe immunosuppression may need testing to assess their immune response to the MMR vaccine; during a measles outbreak to identify susceptible individuals.
In 1996, a large number of people, particularly school-aged children, received measles vaccinations due to a shift to a two-dose measles-containing vaccine schedule and catch-up campaigns to address the need for better protection against measles, a highly contagious disease.
Where can an individual seek testing for immunity, if needed?
Individuals must be referred for testing from a health care provider. For most individuals, 2 doses of vaccine are recommended over blood testing.
Adapted from Simcoe Muskoka District Health Unit
April 2, 2025
