Effect of corona measures on carriage of pneumococci and group A streptococci

During the COVID-19 pandemic, a sharp decrease in the incidence of invasive bacterial infectious diseases was observed. Shortly after the pandemic and the lifting of lockdown measures, the Netherlands experienced an increase in the incidence of invasive S. pyogenes infections. Bacterial carriage is often a prerequisite for the development of bacterial disease. This study sought to map changes in prevalence and density of S. pneumoniae and S. pyogenes carriage by comparing the results of analyzes of samples from cohorts from the beginning and end of the pandemic (SARSLIVA-1 and SARLSIVA-2 cohorts) with other pre-pandemic, pandemic and post-pandemic cohorts (in collaboration with project 10430372310016). A post-pandemic increase in S. pyogenes carriage among young children (<5 years) was observed while the prevalence of S. pneumoniae carriage among children remained the same. The post-pandemic carriage density of S. pyogenes was increased among old children (≥5 years). These observations suggest that the increase in S. pyogenes invasive disease has been preceded by changes in carriage.