Wilkinson K, Righolt CH, Kwong JC, et al. - Researchers used Manitoba’s provincial immunization and communicable disease registries to determine pertussis vaccine effectiveness (VE) as well as the duration of protection in Manitoba. The matching of people with laboratory-confirmed pertussis in Manitoba diagnosed between April 1, 1992, and March 31, 2015, to up to five population-based controls was done, using a nested case-control design, on age, gender, geography, and case physician or number of physician visits. This analysis was done using data on 534 eligible cases and 2,614 controls. For acellular pertussis (aP)-containing vaccines, the adjusted VE estimate was 85% (95%CI: 74–91%); VE was estimated to be 89% (66–96%) one to three years following the last vaccination. Based on the estimates obtained, the efficacy of aP vaccine in preventing pertussis was suggested since its inception in Manitoba. During a large outbreak, a lower VE was reported, emphasizing the significance of individually examining outbreak periods when estimating pertussis VE over time.