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Measles for Healthcare Providers

Measles is a highly contagious viral infection that spreads through the air when an infected person breathes, coughs or sneezes.

Measles can result in complications such as pneumonia, ear infections, brain infections, other infections and infrequently, death can occur.

 

Reporting positive cases to public health

Measles is a reportable disease and any suspected cases should be reported immediately to public health.

To report a confirmed or probable case of measles, please call us at 519-663-5317.

 

Inclusion of measles in differential diagnosis

With rising global cases, the need to include measles in your differential diagnosis, particularly in returning travellers with respiratory symptoms or rash, has become even more important.

For more information, please visit Infectious Diseases Protocol: Appendix 1 – Case Definitions and Disease - Specific Information: Measles from the Ministry of Health.

Isolation guidelines for suspected cases

Suspected measles cases should be placed under airborne precautions and tested. The Public Health Ontario Measles: Information for Health Care Providers provides practical guidance on infection prevention and control practices for handling suspected cases of measles on page four of the document.

Testing for measles

With the rise in cases, there has been an increase in testing and testing errors have been identified. Serology alone is unable to confirm current measles infection. A nasopharyngeal or throat PCR and a urine PCR are also required.

See specimen requirements in Public Health Ontario Laboratory Test Information Sheet For Measles for more information.

Treatment

There is no treatment for this viral illness. Supportive measures can be taken to relieve sore throat, cough, and fever. Care should be taken not to expose others to infection by staying home and not allowing others to visit for at least four (4) days after the start of the rash. Immunization prior to exposure is the best defense against infection.

Vaccination

In recent years, there has been increased measles activity globally. Through travel, this has resulted in seeing more measles cases locally in Ontario as well. To prevent the spread of measles, providing two doses of MMR vaccine provides close to 100% efficacy in children.
Healthcare providers should continue to reinforce that vaccines are safe and highly effective in preventing disease transmission. Support patients in receiving all routine vaccinations (including measles) according to the Publicly Funded Immunization Schedules for Ontario found on the Ministry of Health’s Vaccine Resources for Professionals website.

Vaccine Dose Eligibility
All individuals who have two documented doses are already considered immune. To ensure immunity, healthcare providers may consider administering the vaccine at an earlier age than the routine immunization schedule for children travelling outside of Canada where the disease is of concern or travelling to locations experiencing measles outbreaks.2

Publicly funded MMR vaccine can be provided based on the following recommendations:

Age
Current MMR Vaccine Recommendations

Infants and children NOT travelling

  • One dose of MMR vaccine on or after the child’s 1st birthday

  • One MMRV vaccine as the 2nd dose at age 4-6 years

  • It is preferable to give the 2nd dose of MMRV at the start of school (4 yrs), rather than closer to 6 yrs of age.

Infants and children

travelling to areas where measles is circulating, within or outside of Canada.

  • Infants: MMR vaccine can be considered between 6-11 months of age for early protection. Two additional doses of measles-containing vaccine is still required after the 1st birthday.

  • Preschoolers: Consider administering the 2nd dose of MMR vaccine earlier than age 4-6 years (at least 28 days after the previous dose)*

  • Ideally, give measles vaccine at least two weeks before travel.

Born before 1970

  • Generally considered to have natural immunity since measles was circulating globally before 1970. Some of these individuals may be susceptible.

  • Individuals who work in a health care setting must show proof of immunity (record of two doses of MMR vaccine OR serology).

  • Post-secondary students and travellers should consider getting at least one dose of MMR vaccine.

Born in 1970 or later

  • If unknown status, give two doses of MMR vaccine at least 28 days apart.

  • If client only had one dose of MMR vaccine, give the 2nd dose of MMR vaccine at least 28 days after the 1st dose.

  • If client had two doses of MMR vaccine, consider fully immunized – no serology required.  

All others

  • All Ontario residents, regardless of date of birth, are eligible for two publicly funded doses of measles-containing vaccine based on the health care provider’s clinical judgment and the needs of the patient (e.g., health care worker, post-secondary student, planning to travel where measles is circulating).

  • Note: Vaccination over serology is generally preferred. See below for information about individuals with missing immunization records.

*MMR and MMRV are live virus vaccines. Two live vaccine doses can be given on the same day or at separated as per recommendations (e.g., MMR and VAR). MMR must be separated 28 days from another MMR or a VAR vaccine, but at least 6 weeks is required between MMR and MMRV.
Preschool children who are given their 2nd dose of measles vaccine prior to age 4 yrs should receive MMR (not MMRV), according to Ontario’s Publicly Funded Schedule. A single antigen VAR vaccine can then be given between 4-6 years of age if a 2nd MMR dose was administered earlier. MMRV is only publicly funded for individuals who are 4-12 yrs of age in Ontario. At other ages, these antigens must be given separately as MMR and VAR vaccines.

Pregnancy and Breastfeeding

Measles-susceptible individuals who are pregnant should wait until after giving birth to get vaccinated with MMR vaccine. Susceptible individuals who are breastfeeding can be vaccinated with MMR vaccine. If planning for pregnancy, it is ideal to delay pregnancy for at least four weeks following vaccination with MMR vaccine.

Immunization of Individuals with Missing Immunization Records

If a patient’s immunization records are unavailable, immunization with measles-containing vaccine is preferable over ordering serological testing to determine immune status. This avoids the potential for false positive and/or false negative results, reduces the risk of missed opportunities for immunization and is consistent with advice from the CIG. It is safe to give additional doses of MMR vaccine to those who are already immune. Routine serological testing to determine immunity in healthy individuals is not routinely recommended.(Cited from: Measles: Information for Health Care Providers (Public Health Ontario)) 

Resources

For general information about the measles virus, how it is spread, signs and symptoms, travel health advice, and other information geared towards the public, please visit our measles webpage.

 

References

2Government of Canada. (2024 April 15). Measles: Travel health advice. Retrieved from
https://www.canada.ca/en/public-health/services/diseases/measles/latest-travel-health-advice.html
3Public Health Agency of Canada. (2025 February 13). National Advisory Committee on Immunization: Summary of NACI statement of February 13, 2025: Updated recommendations on measles post-exposure prophylaxis.  Retrieved from
https://www.canada.ca/en/public-health/services/publications/vaccines-immunization/national-advisory-committee-immunization-summary-updated-recommendations-measles-post-exposure-prophylaxis.html