Peripartal anti-SARS-CoV-2-IgA/IgG in asymptomatic pregnant women during regional SARS-CoV-2-outbreak

The Severe Acute Respiratory Distress Corona Virus 2 (SARS-CoV-2) pandemic poses special challenges for the society and especially the medical staff. Even if a rather mild course is assumed among pregnant women the measures to prevent transmission of the infection are of outstanding importance.

To screen asymptomatic pregnant women during admission to our university maternal hospital we focused on anti-SARS-CoV-2-specific IgG and IgA antibody responses. Hundred and fifty one women admitted to the hospital for childbirth or caesarean delivery were included. In case of suspicious anti-SARS-CoV-2-antibody levels an RT-PCR was performed to confirm an ongoing infection with SARS-CoV-2.

A total of 89% showed negative results for anti-SARS-CoV-2-IgA antibodies, whereas 3% were borderline and 7% positive (both labeled as suspicious). In only one patient with suspicious serology we detected SARS-CoV-2-RNA in the following RT-PCR. 2% presented anti-SARS-CoV-2-IgG antibodies, all being positive for anti-SARS-CoV-2-IgA. The observed positive rate of our study collective of 10.6% seemed much higher than the expected one (1.3%) based on the reports of the Robert Koch Institute and the specifications given by the test's manufacturer. The expected positive predictive value (PPV) was 4.3-6.7 times higher than the observed one.

To our knowledge this is the first report of anti-SARS-CoV-2-antibody levels in the peripartum period of asymptomatic women. As the positive anti-SARS-CoV-2 serology poorly correlated with the confirmatory RT-PCR and the fact that mainly the detection of the virus by PCR correlates with the patient's infectiousness we suggest to rather perform a SARS-CoV-2-PCR-based admission screening in perinatal centers to prevent the spread of the disease.