Pathogen- and type-specific changes in invasive bacterial disease epidemiology during the first year of the COVID-19 pandemic in the Netherlands (preprint)

ABSTRACT

The COVID-19 control measures have resulted in a decline in several invasive bacterial disease caused by Neisseria meningitidis (IMD), Streptococcus pneumoniae (IPD) and Haemophilus influenzae (Hi-D). Since these species comprise different serogroups and serotypes that impact transmissibility and virulence, we evaluated type- and pathogen-specific changes in invasive bacterial disease epidemiology in the Netherlands during the first year of the SARS-CoV-2 pandemic. Cases were based on nationwide surveillance for five bacterial species with either respiratory (IMD, IPD, Hi-D) or non-respiratory (controls) transmission routes. Cases and type-distribution were compared between the pre-COVID period (2015-March 2020) and the first COVID-19 year (April 2020-March 2021). Overall, IMD, IPD, and Hi-D cases decreased by 78%, 67%, and 35%, respectively, in the first COVID-19 year compared to the pre-COVID period although effects differed per age group. Invasive bacterial disease in infants caused by Streptococcus agalactiae and Escherichia coli did not decrease, suggesting stable isolate submission. Serogroup B-IMD declined by 61%, while serogroup W and Y-IMD decreased >90%. Changes in IPD were dependent on pneumococcal serotypes, with 7F, 15A, 12F, 33F, and 8 showing the most pronounced decline ([≥]76%). In contrast to an overall decrease in Hi-D cases, vaccine-preventable serotype b (Hib) increased by 51%. In summary, the implementation of COVID-19 control measures had pathogen- and type-specific effects related to bacterial infections, likely reflecting intrinsic differences in transmissibility and age-related differences in (adherence to) control measures. Continued surveillance is critical to monitor potential rebound effects once restriction measures are lifted and transmission is resumed.