Evidence for and against vertical transmission for SARS-CoV-2 (COVID-19).

Abstract COVID-19 can severely affect pregnant women and the issue of vertical transmission of sars-cov-2 has also emerged. Sars-cov-2 could be recovered by real-time (RT) PCR from nasal and throat swabs, sputum and feces of symptomatic patients including neonates but not from vaginal swabs, amniotic fluid, placenta, cord blood, neonatal blood or breast milk. Viremia was present in 1% of symptomatic adults. We identified 12 articles published between February 10th and April 4th 2020 reporting on 68 deliveries and 71 neonates with maternal infection in the third trimester of pregnancy. Perinatal exposure, including mode of delivery and time interval from delivery to the diagnosis of neonatal infection are crucial in differentiating congenital from perinatal infection. Neonatal infection is usually asymptomatic. Neonatal infection was diagnosed within 48 hours of life in 4 cases. Detection rates of real-time PCR and the interpretation of IgM and IgG antibodies levels in cord and neonatal blood are discussed in relation with the immaturity of the fetal and neonatal immune system.