Age Differences in Pertussis Epidemics, New South Wales, Australia, 2015 and 2024

We compared data from the 2015 and 2024 pertussis epidemics in New South Wales, Australia. In 2024, we found twice as many notifications and a shift in distribution to older children. COVID-19 interventions and lack of circulation of pertussis likely contributed to an age cohort immunity gap and increased infections.