Pertussis Vaccination During Pregnancy Regional Situation and Impact of Implementation on National Immunization Programs in Latin America

Background: Infants face a high risk of morbidity and mortality from pertussis early in life, leading to the adoption of maternal vaccination. This study aimed to review the characteristics of the maternal pertussis vaccination in Latin American (LATAM) countries and evaluate their impact on pertussis absolute mortality and case fatality rate (CFR) in infants under 1 year old. Methods: LATAM countries with maternal tetanus, diphtheria and acellular pertussis (Tdap) vaccination in their National Immunization Programs were included. Data on pertussis incidence, deaths and cases in <1-year-old; characteristics of Tdap vaccination in pregnancy; and third dose of diphtheria, tetanus and pertussis and Tdap coverage rates were collected and analyzed. The impact on absolute mortality and CFR was assessed by comparing the percentage reduction between 4 years before and after (up to 2019) the Tdap introduction for each country. Results: The LATAM countries included were Argentina, Brazil, Chile, Costa Rica, Colombia, El Salvador, Mexico, Panamá, Paraguay, Peru and Uruguay. Post-Tdap introduction, pertussis incidence declined notably, especially from 2020. The beginning of the maternal Tdap strategy varied, occurring between 2012 and 2019, with a common recommendation at 20 weeks gestation. In most countries, absolute mortality and CFR decreased, though variations ranged from −9.9% to 88.9% and −60.6% to 81.2%, respectively. Tdap and third dose of diphtheria, tetanus and pertussis coverage rates declined by 2021, with rates ranging from 37% to 92% and 58% to 95%, respectively. Conclusion: The characteristics of maternal Tdap vaccination varied across LATAM countries. The vaccine implementation into the National Immunization Program has reduced pertussis cases, deaths and CFR in infants <1-year-old in most countries.