Authors in Peru have reported on what may be the earliest positive polymerase chain reaction (PCR) for SARS-CoV-2 in serum from a neonate, which occurred 16 hours after birth. Published in the American Journal of Perinatology, the case may represent vertical transmission in utero although no testing was done for presence of virus in amniotic fluid, cord blood, or placental tissue.
The mother, a 41-year-old G3P2, presented at 33 weeks’ gestation with a 4-day history of malaise, low-grade fever, and shortness of breath. Her partner and two children were symptomatic for COVID-19 in the 15 days before the woman’s admission and the partner tested positive while the patient was hospitalized.
A nasopharyngeal swab for SARS-CoV-2 RT-PCR from the woman was positive the day after admission. Because of her compromised respiratory status, which required intubation and mechanical respiration, a cesarean delivery was performed. The neonate was intubated and taken to the neonatal intensive care unit, isolated from other COVID-19 cases. Chest x-ray showed no abnormalities but his SARS-CoV-2 RT-PCR was positive at 16 hours after delivery, and when repeated at 48 hours, the result was the same.
Maternal serology was negative for IgG and IgM on postpartum Day 1 but positive on postpartum Day 4.
For 12 hours, the infant was on ventilatory support. He was then extubated and placed on continuous positive airway pressure. On Day 6, he had mild respiratory difficulty and sporadic coughing, for which supplemental oxygen through a nasal cannula was required but imaging and laboratory tests remained normal.
The authors theorize that the negative serology in the infant through Day 5 might be “explained by the immaturity of the adaptive immunity in the neonatal period, especially seen in preterm neonates, which results in impaired cytokine and B-cell immunoglobulin production relative to adults.” They acknowledged that perinatal transmission is possible in this case because of the lag time to neonatal nasopharyngeal swab.