Discussion
The index case is a term newborn baby with nasopharyngeal swab sample testing positive by reverse-transcription polymerase chain reaction (rRT-PCR) for SARS -CoV-2 infection at 24 hours after birth. During the whole hospital course, the patient was stable.
Several studies in newborn infants are currently available, suggesting that infants usually have mild manifestations of the disease, which were consistent with our case report 2-4.
However, a reported clinical analysis proposed that infants with SARS -CoV-2 infection may present with premature delivery, respiratory distress, gastrointestinal symptoms, laboratory results abnormalities like elevated liver enzymes, thrombocytopenia, and increased mortality rate 5.
One of the primary risk factors of COVID-19 infection is considered close contact with an infected person within 14 days of symptoms onset and an incubation period ranging
between 2 to 14 days, an average of five days. Presently, the possibility of vertical transmission is a big question to neonatologists and obstetricians. There is limited evidence for mother-to-child transmission in women who developed SARS -CoV-2 in late pregnancy.
However, Wang et al. recently described cases of newborn infants with proven COVID-19 infection where the nasopharyngeal swabs were taken 36 hours after birth4.
A recently published cohort study identified three newborn infants with COVID-19. All these cases were delivered by the emergency cesarean section because of fetal distress and had confirmed maternal SARS -CoV-2 infection. All neonates had nasopharyngeal and anal swab positive for COVID-19 on day 2 of life despite strict infection prevention and control during procedures that were done throughout the delivery6.
Also, Lan Dong et al. reported a newborn baby with elevated anti-SARS-CoV-2 IGM antibodies two hours after the birth, and there was no physical contact with the COVID-19 positive
mother 7. Detection of IgM is suggestive of the intrauterine infection. Interestingly, at the same time several requested nasopharyngeal swabs for COVID-19 were negative in the same baby.
All these neonates were isolated from the mother from the beginning, including our case, suggesting the possibility of vertical transmission in these reported cases. There is also other evidence supporting the ability of vertical transmission of SARS-CoV-2.
The latest reports identified the presence of SARS-CoV-2 in the villous chorion and amniotic fluid 8. The possibility of vertical transmission can occur during vaginal birth with exposure to maternal stool infected with SARS-CoV-2 9. Additionally, SARS-CoV-2 nucleic acid was found in the blood samples10.
Unfortunately, no testing of intrauterine tissue samples as placenta, cord blood, amniotic fluid, and maternal milk was done in the index case to confirm that the SARS -CoV-2 infection occurred due to vertical transmission.