INTRODUCTION: Despite high vaccination coverage, a recent increase in pertussis incidence rates has been observed. The objective of the study was to describe epidemiological trends in pertussis between 2012 and 2024 in the Community of Madrid (central Spain). METHODS: Population-based observational study of pertussis cases reported to the regional epidemiological surveillance system. The cumulative incidence (CI) per 100 000 person-years was estimated for 2012-2015, 2016-2019, 2020-2022 and 2023-2024, as well as the proportion of hospitalizations and timely vaccination. RESULTS: The cumulative incidence for the age groups 1-4 years, 5-9 years, and 10-14 years were, respectively, 24.4, 16.5, and 15.9 cases per 100,000 person-years in 2012-2015 and 40.1, 62.1, and 58.0 cases per 100,000 person-years in 2023-2024. The cumulative incidence in infants aged less than one year was 243.6 cases per 100,000 person-years in 2012-2015 and 160.1 cases per 100,000 person-years in 2023-2024. The proportions of timely vaccination were 49.4, 89.2, 85.3, 79.1, and 67.2% in the <1, 1-4, 5-9, 10-14, and 15-19 years groups, respectively. The median interval between the last vaccination dose and the onset of symptoms was 3.4 years. In the group of infants aged less than 4 months, 52.2% of mothers had been vaccinated during pregnancy. Five deaths occurred among those infants aged less than 3 months whose mothers had not been vaccinated. DISCUSSION: Despite the increase in pertussis in older children and adolescents during the 2023-2024 epidemic wave, a remarkable decrease was observed in infants aged less than 6 months. It is necessary to consolidate the vaccination program during pregnancy, ensure timely vaccination and evaluate the age at which the booster is given in adolescence.
Reques et al. (Mon,) studied this question.