Invasive Pneumococcal Diseases Before and After the COVID-19 Pandemic in Italy (2018-2023)

This study assessed the epidemiological and microbiological invasive pneumococcal disease (IPD) changes that occurred before and after the emergence of COVID-19 in Italy. All IPD cases reported through the nationwide surveillance system during 2018-2023 were included. IPD incidence and serotype distributions were analyzed by age group. IPD incidence in 2020-2021 declined in all age groups compared with 2018-2019, especially in children less than 2 years of age and elderly people aged > 64 years. A resurgence of IPD cases was observed from late 2022 onwards, with values in children exceeding those seen before the pandemic. The post COVID-19 increase in children was mainly driven by some PCV13 serotypes, such as 3, 19A, and 19F, but also non-vaccine serotypes, including 10A, 8, and 24F, while in the elderly population, a predominance of serotypes 3 and 8 was observed. In conclusion, a steep drop in IPD incidence was observed during the peak of the COVID-19 pandemic, followed by a subsequent upsurge of cases, especially in children. Continuous national surveillance is necessary to monitor the dynamics and evolution of IPD and the impact of new higher-valency vaccines in Italy over the next few years.