LAUSR

In Spring 2020, following temporary success during the first wave of the world-wide pandemic of the novel 2019 coronavirus disease (COVID-19) with very few positive cases, the Czech Republic (CZ) subsequently suffered from one of the highest incidences of individuals who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In March 2022, the cumulative number of positive cases reached almost 3.5 million (34.1% of the population). Individual pandemic waves in CZ were characterised with predominant genetic variants, namely: B.1.258 in the second wave in late 2020, alpha (B.1.1.7) in the third wave in early 2021, delta (B.1.617.2) in the fourth wave in late 2021, and finally Omicron (B.1.1.529) in the last wave in early 2022. At the same time, paediatricians faced paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS). The incidence of PIMS-TS among SARS-CoV-2 positive children varies at around 0.3:1000. However, no data have been published on the impact of variants or lineages of SARSCoV-2 on the occurrence of PIMS-TS. The aim of this study was to analyse the association between SARS-CoV-2 lineage and the incidence of PIMS-TS cases.