Measles

Vaccination is the best way to prevent the measles virus. Two doses of measles-containing vaccine (i.e., MMR and/or MMRV) is over 97% effective in preventing a measles infection. 

The measles vaccine is included in Ontario's routine immunization schedule and is provided free of charge if you meet the eligibility criteria.

Infants and children

• The provincial recommendation is for children to receive their first dose of measles vaccine (MMR) at one year of age, and a booster dose (MMRV) between the ages of four and six, preferably before entering school.
• Infants six to 11 months of age should get a dose if they are travelling to an area with increased measles activity.

Adults

• If you were born before 1970 you are considered protected against measles. There are some exceptions, for example healthcare workers and military personnel. Please talk with your healthcare provider if you have questions.
• Adults born in or after 1970 require two doses of measles-containing vaccine if they have not had prior infection with measles.

Pregnant or immunocompromised

• People who are pregnant or immunocompromised (have a weakened immune system) are generally not recommended to receive a measles-containing vaccine. Consult a healthcare provider if you're not previously vaccinated and are at risk of exposure to measles.

It is important for everyone to know your immunization and illness history and to ensure you are up to date with all publicly funded immunizations for which you are eligible, including measles vaccine.

Symptoms of measles begin 7 to 21 days after exposure to the virus. Symptoms often start with:

• fever
• runny nose
• cough, and/or
• red eyes

About three to seven days after symptoms begin, a red blotchy rash appears on the face and then spreads down the body.

The rash can last for four to seven days. Individuals with measles are contagious from four days before the rash begins until four days after the rash starts.

If you think you may have been exposed to the measles virus: 

• Assess your risk of exposure using the online Measles Exposure Self-Assessment Tool.
• Ensure you are up to date with the measles vaccine.
• Contact a healthcare provider if you are at increased risk. Those at higher risk for measles infection include:
  • infants less than 12 months of age
  • pregnant individuals who have not received two doses of a measles-containing vaccine
  • individuals with compromised immune system.
• Monitor for symptoms of measles for 21 days following exposure, even if you are up to date with your measles vaccinations.

Anyone experiencing symptoms should contact their healthcare provider as soon as possible, or contact HPPH’s Infectious Disease team at idteam@hpph.ca or 1-888-221-2133 Ext. 3284.

If you think you have measles:

1. 1. Stay home and avoid contact with others.

   2. Call ahead before you visit a doctor, clinic, or hospital so they can prepare for your arrival and prevent virus spread.

   3. Wear a well-fitted medical mask if you need to go out for medical care.

Your healthcare provider will assess you for measles and may test you if they think you may have measles.

• If you're diagnosed with measles, a healthcare provider or laboratory will report your result to your local public health unit. Your local public health unit will contact you to try to figure out:
  • how you became infected
  • who you've been in contact with to determine if they could have been exposed.

This process, called contact tracing, is carried out to prevent the spread of measles to others.

There is no cure (such as an antiviral or antibiotic) for a measles infection. Most people fully recover from measles within two to three weeks. Sometimes measles can cause complications, such as pneumonia, ear infections, diarrhea, hearing loss, brain swelling (encephalitis), seizures, or, rarely, even death.

About measles | Ministry of Health

Measles: What you should know fact sheet | Health Canada

What should parents know about measles | Children’s Hospital of Eastern Ontario

1. Check your  immunization records (such as the yellow Ontario vaccination card) to see if you have had two doses of measles-containing vaccine after age one.
2. If you cannot find documentation of two doses of measles-containing vaccine, and you or your child’s immunizations were reported to public health, you can check the record online through Immunization Connect Ontario (ICON).
3. If you still cannot find documentation of two doses of measles-containing vaccine, ask your healthcare provider to provide your immunization record. Your previous healthcare provider may also have immunization records that may be requested. 

If no immunization record can be found, assume you are unvaccinated. Book an appointment with your healthcare provider to discuss next steps. 

With measles circulating, campers and staff need to be aware of additional requirements regarding measles:

• All campers and staff need to come to camp with their own up-to-date measles immunity information readily available.
• It is recommended that all camp staff check their immunization records to ensure protection against the measles virus. If you are born after 1970 and do not have two doses of measles-containing vaccine, book an appointment with your healthcare provider to assess your immunity and bring your immunizations up to date.
• If there is a case, exposure, or outbreak at your camp, individuals in the camp (including counsellors, kitchen staff, custodial staff and children) may be required to self-isolate. Most camp settings will not be able to offer self-isolation on site, and therefore the following individuals will be excluded from attending the camp:
  • individuals who are symptomatic cases AND
  • exposed persons who do not have immunity, which means:
    • they are not up to date with their measles immunizations, OR
    • they do not have proof of measles immunity (bloodwork showing antibodies to measles), OR
    • they do not have proof of previous measles infection (such as healthcare provider attestation)
  • Campers and staff who have a valid medical contra-indication to measles vaccine will also be excluded. This is to protect the non-immune individuals from health risks associated with a measles exposure. HPPH will work with camp operators should there be a measles case, exposure or outbreak.
• Camp operators should have a process to recognize measles symptoms early, to promptly isolate symptomatic persons and to promptly report to public health. Reports to public health can be made by contacting the HPPH infectious disease team at 1-888-221-2133 ext. 3284.
• As always, advise families that ill campers are not to attend camp. Also, campers cannot attend camp if they have been exposed to measles and have been directed to self-isolate.

Read the full Camp Operator Letter May 2025

Measles is a reportable disease in Ontario, which means healthcare providers and hospitals must report suspect and confirmed cases of measles to the local health unit. Measles is diagnosed by a healthcare provider.

When a health unit such as HPPH receives a report about suspect or confirmed measles, a risk assessment and contact tracing investigation begins.  HPPH then reaches out to everyone who may have been exposed.  If during a contact tracing investigation we cannot reach everyone who was exposed, we notify the public of a possible "community exposure." 

If there is an exposure at your school, HPPH will notify everyone who may have been exposed. Also, individuals in the school (such as educators, support staff, and students) who are not up to date with their measles immunizations, who do not have proof of measles immunity, or who have a documented vaccination exemption and are thus susceptible to measles, may be excluded from attending school. This is to protect unimmunized individuals from health risks associated with a measles exposure.  

Measles is currently circulating in Huron and Perth among undervaccinated people. The best way to protect you and your family from getting measles is to ensure you are all up-to-date on your vaccinations. Two doses of measles-containing vaccine (i.e., MMR and/or MMRV) is over 97% effective in preventing a measles infection. 

Those at higher risk for measles infection include:

• infants less than 12 months of age
• pregnant individuals who have not received two doses of a measles-containing vaccine
• individuals with compromised immune systems.

Vaccination is not an option for some of those at higher risk (e.g. pregnant individuals, infants less than 6 months of age, etc.). Because measles is currently circulating in Huron-Perth, high-risk individuals can consider additional precautions such as:

• Ensure household members and other close contacts are up to date on their measles vaccinations.
• Choose activities that are lower risk, and reduce your chances of being in contact with ill people:
• Outdoor events are safer than crowded, indoor events.
• Choose/host events where people have been asked to stay home if they are ill with measles symptoms or if they have been recently exposed to measles.

To report a suspect case of measles or exposure:
E-mail the Infectious Disease team at IDteam@hpph.ca (indicate urgency/healthcare provider in subject line for quickest response)

To ask about measles vaccine:
E-mail the Immunization team at immunization@hpph.ca (indicate urgency/healthcare provider in subject line for quickest response)

Urgent requests
If you need an urgent consultation, please call 888-221-2133 press 1 and advise Reception that you are a healthcare provider with an urgent measles-related matter.

HPPH Public Health Update MMR/MMRV Vaccines April 4 2025

HPPH Public Health Update Measles March 31 2025

HPPH Public Health Update Measles March 18 2025

HPPH Public Health Update Measles March 11 2025 

HPPH Public Health Alert Measles March 6 2025

HPPH Public Health Update Measles ERs February 25 2025

HPPH Public Health Update Measles January 31 2025

Measles Information for Healthcare Providers | Public Health Ontario

Measles in Ontario: Enhanced Epidemiological Summary | Public Health Ontario