Immunological assessment of SARS-CoV-2 Infection in Pregnancy From
Diagnosis to Delivery: A multicentre prospective observational study
Abstract
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.