Assessment of SARS-CoV-2 Vertical Transmission through Nested RT-PCR Testing of Neonatal Samples: Three Case Reports

Abstract

The novel Coronavirus Disease 2019 (COVID-19) pandemic has drawn attention to the possible transplacental transmission of SARS-CoV-2 and the consequences to the fetus and newborn, despite initial assumption that there was no possibility of coronavirus transmission from the mother to the fetus. More recently, cases of newborns infected with the novel coronavirus have been reported in the scientific community. We present three cases of pregnant women with positive SARS-CoV-2 antibody serology on admission to the Marcílio Dias Naval Hospital, Rio de Janeiro, Brazil, and the diagnostic tests performed on the newborns. RT-PCR tests were negative for all neonatal nasopharyngeal swab samples tested, although SARS-CoV-2 was detected in amniotic fluid and umbilical cord blood using nested PCR techniques, thus successfully demonstrating transplacental transmission. We suggest that nasopharyngeal swab PCR tests of neonates may have some limitations for the investigation of transplacental infection, therefore, this molecular test needs more attention for this kind of investigation.