Compliance with ethical standards: the study was approved by the Ethics Committee of Filatov City Clinical Hospital No. 15 (Protocol No. 5 dated May12, 2020). Informed consent was obtained from all study participants or their legal representatives.

Author contribution: Semeshkin AA — data acquisition, blood collection for antibody tests in neonates, nasopharyngeal swab collection for PCR tests in neonates, analysis of the obtained data, manuscript preparation; Vechorko VI, Averkov OV — study planning, analysis of the obtained data; Silaev BV — study planning, blood collection for antibody tests in mothers, nasopharyngeal swab collection for PCR tests in mothers, data analysis, literature analysis, manuscript preparation; Levchuk NN — data acquisition, laboratory tests for IgM and IgG, analysis of the obtained data; Polikarpova SV — data acquisition, PCR tests in mothers and neonates, literature analysis, analysis of the obtained data.