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

A research study compared two pertussis (whooping cough) epidemics in New South Wales, Australia in 2015 and 2024. In 2024, twice as many cases were recorded compared to 2015 – specifically 25,695 cases versus 12,007 cases. The notification rate increased from 157.7 to 314.7 cases per 100,000 population. A significant difference was observed in the age distribution shift – in 2024, children aged 10–14 years dominated (38% of cases), whereas in 2015 it was children aged 5–9 years (25.2% of cases). The proportion of cases in children under 5 years decreased from 15.1% to 8.3%. The authors attribute these changes to the impact of COVID-19 interventions and the creation of immunity gaps in certain age groups.