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Measles and Immunizations
Vaccine background
- Immunization provides the best protection against measles infection.
- Measles containing vaccines include Measles-Mumps-Rubella (MMR) vaccine and Measles-Mumps-Rubella-Varicella (MMRV) vaccine.
- Vaccination coverage needs to be at least 95% to develop herd immunity in a population and prevent transmission of the infection. In Ottawa, immunization coverage against measles is high.
Vaccine effectiveness
- ~85-95% of children will develop long-lasting protection against measles from the first dose of vaccine; close to 100% of children will have developed immunity to measles after the second dose.
- Immunity following vaccination is generally lifelong.
Recommendations
- The Ontario Routine Immunization Records recommends two-doses of a measles-containing vaccine be given to children, given at least 1 month apart, after 12 months of age and again at 4 to 6 years of age.
- High Risk Eligibility Criteria (Table 3 of Publicly Funded Immunization Schedule for Ontario June 2022 (gov.on.ca) include:
- If a child is travelling internationally to areas where measles is circulating, an initial dose of MMR vaccine can be given as early as 6 months, however, 2 additional doses of a measles-containing vaccine given at least 1 month apart must be administered after the child is 12 months old to ensure long lasting immunity to measles.
Immunization records
- Parent(s)/Guardian(s) are responsible for updating Public Health every time their child receives immunizations given by their physician or health care professional.
- Physicians and health care professionals are not mandated to report immunizations to Ottawa Public Health.
- Patient can update their immunization records with Ottawa Public Health using either the online Immunization Connect Ontario (ICON) Tool or the CANImmunize App.
Contraindications
- Measles vaccine precautions and contraindications can be found in the Canadian Immunization Guide
Considerations for adult immunizations
- Adults born after 1970 may be under-immunized, having received only one MMR vaccine in childhood. If documentation of two measles-containing vaccines, given at least 1 month apart, after 12 months of age, is not available, immunization with MMR vaccine is recommended (without first checking serology for immune status).
- Although most adults born before 1970 are considered to be immune from measles, there are several populations who require immunization*:
- Travel: Those born before 1970 who plan to travel outside North America are recommended to have one dose of MMR vaccine.
- Students in post-secondary educational settings require two doses of MMR vaccine (given at least 1 month apart, after 12 months of age) regardless of year of birth.
- Health care workers require either 2 doses of a measles-containing vaccine (given at least 1 month apart, after 12 months of age), regardless of year of birth.
- Members of the military require either 2 doses of a measles-containing vaccine (given at least 1 month apart, after 12 months of age) regardless of year of birth.
- *Immunization is not required if they have a history of laboratory confirmed measles or measles serology to prove immunity.
- More details regarding requirements for immunity in special populations can be accessed from the Ontario Ministry of Health and in the Canadian Immunization Guide (Measles Vaccine: Table 1).
- Unknown immunization status: Immunization vs. Serology
- If a patient’s immunization records are unavailable, immunization with measles-containing vaccine is preferred, rather than ordering serology to determine immune status.
- This avoids the potential for false positive results, reduces the risk of missed opportunities for immunization and is consistent with advice from the Canadian Immunization Guide
- Please note this may not apply to specific occupational groups such as health care workers who require either documentation of immunization or serologic proof of immunity. Please refer to the Ontario Hospital Association Measles Surveillance Protocol for more information.
Adverse events
- Measles-Mumps-Rubella (MMR) vaccine: Adverse events following immunization occur less frequently and are less severe than those associated with natural infection. Six to 23 days after immunization with MMR vaccine, approximately 5% of immunized children experience malaise and fever (with or without rash) lasting up to 3 days. Parotitis, rash, lymphadenopathy, and joint symptoms also occur occasionally after immunization with MMR vaccine.
- Measles-Mumps-Rubella-Varicella (MMRV) vaccine: Pain and redness at the injection site or fever less than 39°C occur in 10% or more of vaccine recipients. Rash, including measles-like, rubella-like and varicella-like rash, as well as swelling at the injection site and fever greater than 39°C, occur in 1% to less than 10% of vaccine recipients