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Assessing safety of Ontario's publicly funded MMR and MMRV immunization programs, 2012 to 2016
Chi Yon Seo1, Mohammed Rashid1,2, Tara Harris1
1Public Health Ontario, Toronto, Ontario.
Background:
The combined measles, mumps, rubella (MMR) and measles, mumps, rubella, and varicella (MMRV) vaccines are part of Ontario's routine immunization schedule.
Objective:
To assess adverse events following immunization (AEFIs) reported in Ontario following administration of MMR and MMRV vaccines between 2012 and 2016.
Methods:
Reports of AEFIs were extracted from the provincial surveillance database on May 9, 2017. Events were grouped by provincial surveillance definitions. Reporting rates were calculated using provincial population estimates or net doses distributed as the denominator. A serious AEFI is defined as an AEFI that resulted in an in-patient hospitalization or death.
Results:
Overall, 289 AEFIs were reported following administration of MMR (n=246) or MMRV (n=43) vaccines, for annualized reporting rates of 16.6 and 8.8 reports per 100,000 distributed doses, respectively. The highest age-specific reporting rate was in children aged 1 to 3 years for MMR (7.7 per 100,000 population) and children aged 4 to 9 years for MMRV (0.8 per 100,000 population). Systemic reactions were the most frequently reported event category, while rash was the most frequently reported event for both vaccines. There were 22 serious AEFIs, 19 following MMR and 3 following MMRV (1.3 and 0.6 per 100,000 doses distributed, respectively).
Conclusions:
Our assessment found a low reporting rate of adverse events following MMR and MMRV vaccines in Ontario. No safety concerns were identified. Our findings are consistent with the safety profiles of these vaccines. Continued monitoring of vaccine safety is necessary to maintain timely detection of unusual postvaccine events and public confidence in vaccine safety.
Insights
Adverse events following measles, mumps, rubella (MMR) and MMRV vaccination in Ontario were rare between 2012-2016. The study found no new safety concerns, supporting the established safety profiles of these routine childhood vaccines.
Area of Science:
- Immunization and Vaccine Safety
- Public Health Surveillance
- Pediatric Infectious Disease
Background:
- Measles, mumps, rubella (MMR) and measles, mumps, rubella, and varicella (MMRV) vaccines are integral to Ontario's routine immunization schedule.
- Understanding vaccine safety is crucial for maintaining public trust and adherence to immunization programs.
Purpose of the Study:
- To evaluate adverse events following immunization (AEFIs) reported after MMR and MMRV vaccine administration in Ontario.
- To identify any potential safety signals associated with these widely used vaccines during a defined period.
Main Methods:
- AEFI reports were extracted from Ontario's provincial surveillance database (data up to May 9, 2017).
- Events were categorized based on provincial definitions, and reporting rates were calculated using population estimates or distributed doses.
- Serious AEFIs, defined as those leading to hospitalization or death, were specifically analyzed.
Main Results:
- A total of 289 AEFIs were reported for MMR (n=246) and MMRV (n=43) vaccines, with low annualized reporting rates per 100,000 doses.
- Systemic reactions and rash were the most common reported events for both vaccines.
- Twenty-two serious AEFIs were documented, with higher rates following MMR compared to MMRV vaccines.
Conclusions:
- The study indicates a low rate of adverse events following MMR and MMRV vaccination in Ontario.
- No significant new safety concerns were identified, aligning with the known safety profiles of these vaccines.
- Ongoing surveillance is essential for detecting rare post-vaccine events and reinforcing public confidence in vaccine safety.
