Inclusion Criteria:  based on any one of the following criteria: (a) positive RT-PCR nasopharyngeal swab taken (even if the result became available after labor); (b) positive rapid antigen test performed before labor (c) chest computed tomography (CT) scan performed before labor showing changes consistent with pneumonitis secondary to SARS-CoV-2 infection; (d) positive pre-labor immunoglobulin G or immunoglobulin M antibody test; or (e) clinical diagnosis made before labor (in the absence of negative RT-PCR swab results).  Exclusion Criteria:  for healthy control individuals: acute or chronic infectious disease, and any medication with known influence on immunological factors.