Possible intrauterine SARS-CoV-2 infection: Positive nucleic acid testing results and consecutive positive SARS-CoV-2-specific antibody levels within 50 days after birth

Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects the fetus in utero is important to the well-being of the mother and neonate. We report the case of a full-term neonate born to a mother who developed symptoms of coronavirus disease 2019 (COVID-19) at 32 weeks of gestation. The placental pathology showed slight local inflammation. Serial quantitative antibody measurements in the neonate showed elevated levels of IgM on the day of birth and a gradual decline to negative levels within 28 days of life; the levels of IgG declined gradually, but IgG was still positive on day 50 of life. The sequential dynamic changes in antibody levels in the neonate were consistent with those in his mother. One-step reverse transcriptase droplet digital PCR testing for SARS-CoV-2 nucleic acid in throat and anal swabs showed positive results (750 and 892 copies/ml) on day 7 of life and negative results on day 14 of life. The neonate had no symptoms of COVID-19. This report enables us to re-evaluate the significance of IgM detection in intrauterine SARS-CoV-2 infection and presents a favorable prognosis for the neonate with long-term exposure to maternal COVID-19, despite a high possibility of intrauterine infection.