Abstract
Introduction: In order to understand SARS-CoV-2 infection in neonate, our department implemented an ambulatory follow-up program to neonates born to SARS-CoV-2 mothers. The aim of our study was to characterize this population of neonates born to SARS-CoV-2 mothers, analyze SARS-CoV-2 antibodies evolution and evaluate these neonates after hospital discharge.

Material and Methods: Single-center prospective cohort study enrolling all neonates born to mothers with active perinatal SARS-CoV-2 infection in a tertiary hospital in Portugal from April 2020 to October 2021.

Results: There were 3138 deliveries, and 73 neonates (2.3%) were born from mothers with perinatal SARS-CoV-2 infection. Three neonates (4%) had perinatal SARS-CoV-2 infection. Post-discharge follow-up was achieved in 93% (n=68) of neonates. The first call by a physician was performed at a median of 6 days after discharge. Exclusive breastfeeding was found in 46% (n=68) of the mothers during the first appointment.
We performed cerebral ultrasound (CUS) in 93% (n=68) of the newborns during the first month of life and 35% (n=24) of the newborns had nonspecific abnormal cerebral findings. Regarding serology, 55.1% (n=38) infants had positive anti-nucleocapsid antibodies at first 24 hours of life. At one to three months of life, 52.6% (n=20) of these neonates maintained positive antibodies. There was a significant decrease in anti-nucleocapsid antibodies titer since birth (p<0.001, Wilcoxon signed-ranks test), except in four neonates, three of them with perinatal SARS-CoV-2 infection.

Conclusion: We describe our experience following neonates born to mothers with SARS-CoV-2 infection after discharge, considering our hospital COVID-19 policies. The findings of this study suggest an apparently limited impact of maternal perinatal SARS-CoV-2 infection on early neonatal outcomes. Rooming-in mothers and newborns can be safe, as transmission rates of SARS-CoV-2 seem to be low. This article may contribute to a better understanding of SARS-CoV-2 infection in the neonatal period and its short-time consequences.

Key words: SARS-CoV-2, neonate, perinatal infection, follow-up, antibodies