(833) Effect of preexisting infection-induced immunity on neonatal and maternal outcomes of SARS-CoV-2 infection in pregnancy

Objective: To determine if immunity induced by prior SARS-CoV-2 infection improves neonatal and maternal outcomes in patients with re-infection versus initial infection without prior immunity.

Study Design: In May 2020, we instituted universal antepartum SARS-CoV-2 antibody (IgG) screening during the third-trimester blood draw. Those with SARS-CoV-2 IgG screening in the third trimester and positive SARS-CoV-2 PCR testing at the time of admission for delivery from June 2020 to January 2022 were eligible for this analysis. Patients who received SARS-CoV-2 vaccination, monoclonal antibodies, or oxygen support were excluded. Our primary outcome was a neonatal composite of neonatal intensive care unit admission, arterial cord pH < 7.1, APGAR < 7 at 5 minutes, hypoglycemia, hyperbilirubinemia, hypoxic-ischemic encephalopathy, bronchopulmonary dysplasia, retinopathy, sepsis, respiratory support, seizures, meconium aspiration syndrome, necrotizing enterocolitis, hypotension requiring pressors, and perinatal death. Secondary outcomes included the individual components of the neonatal composite and adverse maternal outcomes. Primary and secondary outcomes were compared among those with positive versus negative antepartum IgG screen using chi-square or Mann-Whitney tests as appropriate.

Results: A total of 8551 patients delivered within the study period, with 244 eligible for this analysis. Of these, 98 (40.2%) tested negative, and 146 (59.8%) tested positive for SARS-CoV-2 IgG at the third-trimester visit. Baseline characteristics did not differ between groups. There were significantly fewer patients with COVID symptoms in the group with preexisting immunity compared to the group without (Table). Otherwise, there were no significant differences in maternal or neonatal outcomes between groups.

Conclusion: Many patients found to have COVID infection at delivery already have preexisting immunity to the virus, and these patients have fewer symptoms. Prior infection-induced immunity, however, does not confer protection against adverse maternal or neonatal outcomes.