Changes in Invasive Pneumococcal Disease in the Paediatric Population in the Second COVID-19 Pandemic Year.

Incidence of invasive pneumococcal disease (IPD) decreased worldwide in 2020, coinciding with the implementation of measures to reduce COVID-19 transmission. We evaluated the impact of the COVID-19 pandemic on healthcare demand and IPD in children in 2021 compared to the pre-pandemic period (2018-2019) and the early pandemic period (2020) in a study carried out during 2018-2021 in Catalonia. Incidence rates were compared by calculating the incidence rate ratio (IRR), and expressing percentage changes in IRR as (1-IRR)x100. Compared to 2018-2019, emergency room (ER) visits declined by 21% in 2021 ( p < 0.001), mainly in the first quarter (-39%), and compared to 2020, ER visits increased by 22% in 2021 ( p < 0.001), except in the first quarter. IPD incidence overall was 11.0 in 2018-2019 and 4.6 in 2021 (-58%, p < 0.001); the reduction in incidence was similar in the 0-4 age group and was higher in the first quarters. Compared to 2020, in 2021, IPD incidence decreased during the first quarter (-86%, p < 0.001), but increased from 0.0 to 1.2 in the second quarter ( p = 0.02) and from 0.6 to 2.1 ( p=0.03 ) in the fourth quarter. The decreased IPD incidence observed in 2021 compared to 2018-2019 (most especially in the first quarter) was greater than the decrease in healthcare demand and PCR test requests. Compared to 2020, IPD incidence decreased in the first quarter when a second state of alarm was in force. In 2021, compared to 2018-2019, there was a greater reduction in PCV13 serotypes than in non-PCV13 serotypes.