Periodenprävalenz von SARS-CoV-2 in einer unselektierten Stichprobe schwangerer Frauen in Jena, Thüringen./ [Period Prevalence of SARS-CoV-2 in an Unselected Sample of Pregnant Women in Jena, Thuringia].

INTRODUCTION: Following an exponential increase in SARS-CoV-2 infections, the city of Jena, Thuringia, was the first in Germany to introduce mandatory mouth and nose coverings. An estimation of the SARS-CoV-2 period prevalence was achieved by screening an unselected cohort of pregnant women. Of interest was the number of unreported cases. METHODS: Upon admission to hospital, patients were screened for SARS-CoV-2 by a specific real-time PCR and antibodies determined by a specific SARS-CoV-2 IgG in serum by ELISA. The SARS-CoV-2 period prevalence was estimated using the Clopper-Pearson exact method, the group comparison with Fischer's exact test. RESULTS: From 6 April to 13 May 2020, 234 pregnant women were admitted to the Department of Obstetrics. A total of 225 (96.2%) SARS-CoV-2 PCRs were carried out and all remained negative. Specific IgG antibodies were detected in one (0.6%) of 180 (76.9%) antibody tests performed. The interval estimate of the period prevalence thus results in a 95% confidence interval between 0-1.7%. For 96 households with children, the period prevalence is 0-3.8%, which does not differ from the 0-4.8% for 76 households without children (p=1.00). DISCUSSION: This is the first report on the SARS-CoV-2 period prevalence of an unselected sample of pregnant women in Germany. Antibody testing showed no evidence of the feared high number of unreported asymptomatic SARS-CoV-2 infections. The seroconversion rate was below 1% (0.6%).