Incidence and mortality of pertussis disease in infants <12 months of age following introduction of pertussis maternal universal mass vaccination in Bogotá, Colombia. Issue 46 (27th October 2020) - Carrasquilla, Gabriel
Abstract: Background: Maternal immunization with tetanus, diphtheria, and acellular pertussis (Tdap) vaccine confers protection to young infants. We aimed to describe trends in pertussis incidence and associated mortality in children aged <12 months before and after introduction of maternal Tdap immunization in Bogotá, Colombia. Methods: Data on pertussis-related cases/deaths in infants aged <12 months were collected from SIVIGILA for the period 2005–2016, and compared incidence for the pre-vaccine introduction (2005–2012) and post-maternal Tdap vaccination (2014–2016) periods in infants aged <12 months and in three distinct age-strata; ≤6 weeks, 7–<28 weeks, and 28–52 weeks. Mortality comparisons were performed in all infants <12 months. Results: From 2005 to 2016, 2315 laboratory or clinically-confirmed pertussis cases were reported in infants <12 months of age (278 cases in young infants aged ≤6 weeks); 55 pertussis deaths were reported in children aged <12 months. No pertussis deaths were reported in the 2014–2016 period. Since maternal Tdap introduction in 2013, a consistent decline in pertussis incidence and mortality was observed. In the time-series analysis, incidence declined from 209.4/100, 000 persons (2005–2012) to 49.1/100, 000 persons (2014–2016) in all children <12 months; a 87.5% (95%CI: 77.2-93.2%) reduction. For these same period's incidence in young infants ≤6 weeks declined from 196.7 to 89.6/100, 000 person-years (an 54.4% [95% CI: 35.4–67.9%] reduction). Greater incidence reductions were observed in older infants; 73.4% (95% CI: 68.4–77.6%) in those aged 7–<28 weeks, and 100% in those aged 28–52 weeks. A 100% reduction in Pertussis mortality in infants <12 months was observed. Since Tdap introduction, maternal vaccine coverage rose from <60% in 2013–2015 to 80% in 2016. Conclusions: Implementation of maternal immunization in Bogotá may have contributed to the reduction in pertussis incidence and mortality among infants <12 months of age (ClinicalTrials.gov: NCT02569879). An Audio Summary linked to this article that can be found on Figshare https://doi.org/10.6084/m9.figshare.12943316