Measles
Information for Health Care Professionals
What is measles
Measles is a very contagious virus that spreads easily through tiny droplets in the air that can linger for up to two hours, or land on surfaces. A person with measles can typically infect 12 to 18 other people with no immunity and can spread the virus from four days before to four days after their rash appears.
York Region Public Health takes measles very seriously and investigates all measles cases and exposures.
Community Immunization Clinics
The measles vaccine is part of Ontario’s routine childhood immunization schedule. The first dose is given at 12 months and the second between four (4) – six (6) years of age. These vaccines are safe and two doses can provide up to 97% protection from measles.
York Region Public Health offers free immunization clinics for students aged 4-18 years. The measles (MMR) vaccine is free and available to those who are eligible or overdue and do not have access to vaccines through a health care provider. Vaccines are available by appointment only.
Getting the measles vaccine is the best way to protect yourself and others.
Symptoms and Complications
Measles symptoms may start seven to 21 days after exposure. Generally, illness lasts about 10 days. Measles is contagious 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
Complications
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.
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 have any symptoms of measles:
- Stay 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
- Take private transportation to your appointment
- Wear a well-fitting, high-quality face mask when seeking medical care
- Talk to your healthcare provider about testing
If you think you may have been exposed to measles and do not have any symptoms:
- Visit york.ca/MeaslesReporting to complete a brief contact follow-up survey; this will help York Region Public Health assess your risk (or those present with you) and prioritize contacts at greatest risk of becoming infected
- Check your immunization records to confirm you had two doses of a measles-containing vaccine (MMR or MMRV). You can safely get revaccinated if you do not have immunization records or cannot obtain them. If you are unsure, please call and check with a healthcare provider. Access or update your child's reported immunization records with York Region Public Health online on Immunization Connect Ontario (ICON).
- Call York Region Public Health immediately at 1-877-464-9675 ext. 77280 to report the exposure and discuss next steps
- You may be eligible for a measles-containing vaccine or immunoglobulin (antibodies used post-exposure for susceptible individuals) - this must be given soon after the exposure to reduce the risk or severity of infection. York Region Public Health can determine if you are eligible
- Watch for symptoms for 21 days after the last exposure and inform York Region Public Health if you develop symptoms
Am I at risk of measles?
Review the common scenarios below for guidance.
| Scenarios | Action Required |
|---|---|
| My child is under 12 months of age | Call York Region Public Health at 1-877-464-9675 ext. 77280, Early measles immunization or measles immunoglobin may be offered to prevent or reduce measles illness. |
| I am immunocompromised | Call York Region Public Health at 1-877-464-9675 ext. 77280. Early measles immunization or measles immunoglobin may be offered to prevent or reduce measles illness. |
| I work in the military, or a health care setting, or work/attend a school or child care centre | Call York Region Public Health at 1-877-464-9675 ext. 77280 to discuss the details of your exposure and vaccination status. |
| I am pregnant | Call York Region Public Health at 1-877-464-9675 ext. 77280. Talk to your health care provider. Based on when you were born and your immunization records, you may already be protected. If not protected, measles immunoglobin may be offered to prevent or reduce measles illness. |
| I was born before 1970 | Anyone born before 1970 has likely developed immunity to the virus because measles was present then. If you are unsure, you can safely get the MMR vaccine. |
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 the Public Health Ontario Requisition for Specimen Containers and Supplies 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
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. Review the Public Health Ontario Infection Prevention and Control for Clinical Office Practice document for additional information on infection prevention and control measures.
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. Review the Public Health Ontario Measles: Post-Exposure Prophylaxis for Contacts document for additional information.
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
