Reemergence of Invasive Pneumococcal Disease in Germany During the Spring and Summer of 2021

Background The incidence of invasive pneumococcal disease (IPD) decreased worldwide in 2020 and the first quarter of 2021, concurrent with nonpharmaceutical interventions (NPIs) intended to stymie transmission of SARS-CoV-2. In 2021, the stringency of these NPI strategies has varied. We investigated age- and serotype-specific variations in IPD case counts in Germany in 2020-2021. Methods IPD cases through 30 November 2021 were stratified by age group, serotype, or geographic location. IPD surveillance data in 2020-2021 were compared with (1) IPD surveillance data from 2015-2019, (2) mobility data during 2020 and 2021, and (3) NPI stringency data in 2020 and 2021. Results IPD incidence began to return toward baseline among children 0-4 years old in April 2021 and exceeded baseline by June 2021 (a 9% increase over the average monthly values for 2015-2019). Children aged 5-14 years and adults aged 15-34 or >= 80 years showed increases in IPD cases that exceeded baseline values starting in July 2021, with increases also starting in spring 2021. The age distribution and proportion of vaccine-serotype IPD remained comparable to those in previous years, despite lower overall case counts in 2020 and 2021. The percentage change in IPD incidence compared with the previous 5 years was correlated with changes in mobility and with NPI stringency. Conclusions IPD levels began to return to and exceed seasonal levels in spring and summer 2021 in Germany, following sharp declines in 2020 that coincided with NPIs related to the coronavirus disease 2019 pandemic. Proportions of vaccine serotypes remained largely consistent throughout 2020-2021. Invasive Pneumococcal Disease returned to or exceeded baseline levels in mid-2021 in Germany following substantial decreases in 2020, concurrent with the first wave of the SARS-CoV-2 pandemic. This reemergence was associated with increased mobility and decreased stringency to nonpharmaceutical interventions .

Automated summary

The incidence of invasive pneumococcal disease (IPD) in Germany showed a declining trend in 2020-2021 under the influence of nonpharmaceutical interventions (NPIs), but exhibited variations in age and serotype specificity over time.