Effectiveness of an outbreak dose of mumps-containing vaccine in two First Nations communities in Northern Ontario, Canada

• Published in: Human Vaccines & Immunotherapeutics
• Main Authors: Wallis Rudnick, Sarah Wilson, Jo Ann Majerovich, Michelle Haavaldsrud, Marene Gatali, Cai-Lei Matsumoto, Shelley Deeks
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor & Francis Group 2022
• Subjects: mumps; measles-mumps-rubella vaccine; immunization; outbreak dose; vaccine effectiveness; Immunologic diseases. Allergy; RC581-607; Therapeutics. Pharmacology; RM1-950; Canada; First Nations
• Online Access: https://doi.org/10.1080/21645515.2020.1870909; https://doaj.org/article/1be9be4efcae45d3880923059c2edee0

Between 18 Dec 2017 and 27 June 2018, a mumps outbreak occurred in two Canadian Indigenous communities. An outbreak dose of mumps-containing vaccine was offered as part of control measures. We conducted a cohort study and survival analysis to describe the outbreak and evaluate the outbreak dose, extracting vaccination information on all community members (n = 3,135) from vaccination records. There were 70 mumps cases; 56% had received two pre-outbreak vaccine doses. Those who received a pre-outbreak dose more distantly had higher rates of mumps compared to those with more recent doses (adjusted hazard ratio = 3.4 (95%CI: 0.7–20.6) for receipt >20 years before vs. receipt ≤3 years). During the outbreak, 33% (1,010/3,080) of eligible individuals received an outbreak dose. The adjusted hazard ratio for no outbreak dose receipt was 2.7 (95%CI: 1.0–10.1). Our results suggest that an outbreak dose of mumps-containing vaccine may be an effective public health intervention, but further study is warranted.