Please note: We are currently experiencing some performance issues across the site, and some pages may be slow to load. We are working on restoring normal service soon. Importing new articles from Word documents is also currently unavailable. We apologize for any inconvenience.

Kate Glennon

and 24 more

Objective We profile the maternal and fetal response to SARS-CoV-2 infection in symptomatic and asymptomatic pregnant women and make an assessment of passive immunity to the neonate, Design Multicentre prospective study. Setting Dublin, Ireland Methods RT-PCR for viral RNA via a nasopharyngeal swab was performed using the Cobas SARS-CoV-2 6800 platform. Maternal, and fetal serological antibody response, via umbilical cord bloods, was measured using both the Elecsys® immunoassay, Abbott SARS-CoV-2 IgG Assay and the IgM Architect assay. Main outcome Measure Prevalence of RT PCR positive SARS-CoV-2. Assessment of IgM and IgG anti-SARS-CoV-2 serology antibodies. Results Ten of twenty three symptomatic women had SARS-CoV-2 RNA in a nasopharyngeal swab. Five (5/23, 21.7%) demonstrated serological evidence of anti-SARS-CoV-2 IgG antibodies and seven (30.4%, 7/23) were positive for IgM antibodies. In the asymptomatic cohort, the prevalence of SARS-CoV-2 infection in RNA was 0.16% (1/608). IgG SARS-CoV-2 antibodies were detected in 1·67% (10/598, 95% CI 0·8%-3·1%) and IgM in 3·51% (21/598, 95% CI 2·3–5·5%). Nine women had repeat testing between post baseline. Four (4/9, 44%) remained IgM positive, one IgG positive. IgG anti SARS-CoV-2 antibodies were detectable in cord bloods from babies born to five seropositive women who delivered during the study. Conclusion Using two independent serological assays, we present a comprehensive illustration of the antibody response to SARS-CoV-2 in pregnancy, and show a low prevalence of asymptomatic SARS-CoV-2. Transplacental migration of anti-SARS-CoV-2 antibodies was identified in cord blood of women who demonstrated antenatal anti-SARS-CoV-2 antibodies, raising the possibility of passive immunity.