Measles
What is measles
Measles is a very contagious virus that spreads easily through the air. This infection can cause serious health problems. When someone with measles breathes, coughs, sneezes or talks, tiny droplets containing the virus get into the air and on surfaces. You can get measles by breathing in these droplets, just by being in a room where a person with measles has been. This can happen even up to 2 hours after that person has left. You can also get measles by touching surfaces where the droplets have landed, then touching their eyes, nose or mouth.
More information is available on the Measles Fact Sheet | English | French
Getting the measles vaccine is the best way to protect yourself and others.
The vaccine that protects against measles is a combination vaccine included in the routine Ontario childhood immunizations schedule in two doses. The first dose, given at age 12 months, is combined with mumps and rubella protection (the “MMR” vaccine). The second dose, typically given at age 4 to 6, is combined with mumps, rubella, and varicella (chickenpox) protection (the “MMRV” vaccine). These vaccines are safe and provide long-lasting protection. Two doses of the vaccines are approximately 97% effective in preventing measles infection.
York Region Public Health takes measles very seriously and investigates measles cases and exposures. If you were exposed to measles and are at risk of infection, York Region Public Health will contact you and provide advice. For more information about the current measles situation in Ontario, refer to the Public Health Ontario’s Measles Surveillance Report and Measles Exposure Locations in Ontario.
Symptoms and illness
Measles symptoms may start seven to 21 days after exposure. Generally, illness lasts about 10 days. Measles is infectious as soon as symptoms start. The typical measles rash is usually not the first symptom to appear.
Symptoms include:
- Dry cough
- Runny nose and/or sneezing
- Fever
- Red and watery eyes (pink eye or conjunctivitis)
- Sensitivity to light
- Small white spots with a white centre inside the mouth (Koplik spots)
- A red, blotchy rash that typically starts at the head and spreads down the body to the arms and legs. It usually appears three to seven days after the other symptoms begin, and disappears in the same order of appearance (from head to foot) in about four to seven days
Most people recover completely from measles, but the infection can cause complications such as ear infections, lung infections, inflammation of the brain, permanent brain damage and death.
Complications
Measles can be serious in all age groups if you are not vaccinated. However, several groups are more likely to develop complications from measles infections:
- Infants and young children under five years of age
- Pregnant people who are unimmunized are at an increased risk of miscarriage or premature delivery and low birth weight of infant
- People with weakened immune systems
What if I think I have measles?
If you think you have measles, it is important to:
- Staying home (do not go to school or work) and avoid contact with others
- Call ahead before going to a clinic or hospital and let them know of your symptoms or recent exposure so they can prepare for your arrival to prevent the virus from spreading to others
- Wear a well-fitting, high-quality face mask when seeking medical care
If you have been in contact with a person who has measles and do not have any symptoms:
- Call your health care provider to inform them of a measles exposure and confirm your immunization status as soon as possible
- Call York Region Public Health immediately at 1-877-464-9675 ext. 77280 if you have been exposed to measles and share information on other potential cases or exposures
- Some people may be eligible for preventive treatment if they are susceptible to measles and have been exposed, and this must be given soon after the exposure. York Region Public Health can determine if you are eligible
- Regardless of vaccination history, if you have been in contact with a person with measles, you are advised to monitor for symptoms for 21 days after the exposure and inform York Region Public Health if you develop symptoms
- Measles risk varies by age and immunization status. See scenarios below (Am I at risk of measles?) for more information.
Am I at risk of measles?
Two doses of measles containing vaccine can provide protection against measles virus. If you or someone you know is a contact of a measles case and has not had two doses or a prior measles infection, you are considered susceptible to measles.
Review the common scenarios below for guidance.
| Scenarios | Action Required | Comments |
|---|---|---|
| My child is under 12 months of age, and is a close contact of a measles case | Contact York Region Public Health immediately at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess risk. Early measles immunization or measles immunoglobin (blood product) may be offered to prevent or reduce measles illness. | Children under 12 months are at greater risk for complications from measles. Note that if your child receives measles vaccine or immunoglobin before 12 months of age, they will still need two more vaccine doses to provide full protection. |
| I am immunocompromised and am a close contact of a measles case | Contact York Region Public Health immediately at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess risk. Early measles immunization or measles immunoglobin may be offered to prevent or reduce measles illness. | Immunocompromised individuals are at greater risk of complications from measles. |
| I am pregnant and I have not received two doses of measles vaccine and am a close contact of a measles case | Contact York Region Public Health immediately at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess risk. Measles immunoglobin may be offered to prevent or reduce measles illness. You must get the immunoglobin within six days after measles exposure. | You are at high risk of measles infection and at greater risk of complications from measles. |
| I live in the same house as a measles case and have not had two doses of the measles vaccine or have not had measles infection in the past | Contact York Region Public Health immediately at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess risk. Measles immunization or measles immunoglobin may be offered to prevent or reduce measles illness (depending on age and vaccination history). | You are at high risk of measles infection |
| You were born after 1970 and have had no doses or one dose of measles vaccine, no history of past measles infection and are a close contact of a case | Contact York Region Public Health immediately at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess the risk. Measles immunization or measles immunoglobin may be offered to prevent or reduce measles illness (depending on age and vaccination history). | You are at elevated risk of measles infection |
| If you were born before 1970 and are a contact of a measles case | Most people born before 1970 are likely to have had measles in the past and are considered immune. If you work or attend a high-risk setting (e.g., health care worker) contact York Region Public Health at 1-877-464-9675 ext. 77280, seven days a week from 8:30 a.m. to 4:30 p.m. or at 905-953-6478 outside of these times to assess the risk. | You are at lower risk of measles infection |
Diagnosis and treatment
Measles is diagnosed with laboratory tests, including blood, urine, nasopharyngeal and throat tests. Call your health care provider if you have symptoms or were exposed to measles. York Region Public Health will follow up with the diagnosed individual and exposed contacts when a measles case is confirmed. See “What if I think I have measles” section" section above.
There is no specific treatment for measles. Most people can recover at home. Hospitalization may be needed for severe infections. Vaccinating against measles is the best protection.
You can get revaccinated if you do not have vaccination records and cannot obtain them. You can contact your health care provider for more information. York Region parents/guardians can update and look up immunization records for school-aged children.
Information for Health Care Professionals
Measles is a reportable disease requiring all physicians who suspect or diagnose a patient with measles to report to York Region Public Health immediately. Please call us at 1-877-464-9675, ext. 73588, Monday to Friday 8:30 a.m. to 4:30 p.m., or after hours at 905-953-6478 (after 4:30 p.m., weekends, holidays).
Health care professionals should promptly isolate any patient with suspect or confirmed measles in a single room with negative air flow (airborne isolation room) if available, and order the following tests:
| Diagnostic Tests | Specimen Type | Testing Period |
|---|---|---|
| PCR * | Nasopharyngeal (NP) swab | Within 7 days of rash onset |
| Throat swab | Within 7 days of rash onset ** | |
| Urine | Within 14 days of rash onset ** | |
| Acute Serology IgM and IgG *** | Whole blood or serum | Within 7 days of rash onset |
* Collecting a NP swab, throat swab AND urine sample for PCR testing is the preferred way to diagnose measles infection.
** For patients with a high index of suspicion, it may be warranted to test beyond the time periods noted.
*** Serology should NOT be the only test relied upon for diagnosing measles in a symptomatic patient. PCR testing (i.e., NP swab, throat swab and urine) is required in addition to serology.
Please use this form to order specimen collection kits from the Public Health Ontario Laboratory.
For more information, see Measles: Information for Health Care Providers
Infection Prevention and Control Measures
Measles is a virus spread via the airborne route and close contact with respiratory secretions. It is one of the most infectious viruses known. A person infected with measles can pass the virus infection to 12 to 18 others if they are not immunized or have natural immunity from a previous measles infection.
Patients with suspected measles should be promptly isolated in a single room with negative air flow (airborne infection isolation room) with the door closed. If you do not have an airborne infection isolation room, the patient should wear a surgical mask and be immediately placed in a single room with the door closed.
The measles virus can remain in the air for two hours. Therefore, no other patients should be placed in the same room for two hours afterwards. Patient movement should be limited unless absolutely required. Additional information on infection prevention and control measures can be found here.
Post-exposure Prophylaxis
Close contacts of a confirmed case of measles may be eligible for post-exposure prophylaxis (PEP). PEP is given to provide protection and/or modify the clinical course of the disease for individuals who have no immunity and/or are at higher risk of severe outcomes.
York Region Public Health facilitates eligible contacts to receive PEP with a health care provider in the community and/or at a York Region vaccine clinic. PEP includes the administration of the Measles, Mumps and Rubella (MMR) vaccine or serum immunoglobulin (Ig), depending on the age and underlying health of the contact person. Additional information on PEP for contacts can be found here.
Resources for Healthcare Professionals
York Region
- Publicly Funded Vaccines Order Form
- Measles Preparedness – Communication to Health Care Providers (February 5, 2025)
Public Health Ontario (PHO)
- Measles Information for Health Care Providers
- Enhanced Epidemiological Summary: Measles in Ontario
- Measles IPAC Checklist for Clinics and Specimen Collection Centres
- Measles: Post-exposure Prophylaxis for Contacts
Government of Canada
- Measles Vaccines: Canadian Immunization Guide (Public Health Agency of Canada)
- Updated NACI Recommendations for Measles Post-exposure Prophylaxis
Canadian Paediatric Society
World Health Organization
More Information
If you have any questions or require more information about measles and measles vaccination, please call York Region Public Health’s Vaccine Information Line or speak to your health care provider.
York Region Public Health Vaccine Information Line
For issues or reports of any adverse events following immunization or general questions regarding all vaccinations, including COVID-19 and influenza:
- Email address: @email
- Telephone: 1-877-464-9675 ext. 73452
