There was little evidence for vertical COVID-19 transmission among a cohort of newborns whose mothers had confirmed or suspected SARS-CoV-2 infection, according to a study out of New York City.
Among 101 newborns, there was no detection of SARS-CoV-2 viral RNA in 95.7% of nasopharyngeal polymerase chain reaction tests for an overall transmission incidence of 2% in two newborns, reported Cynthia Gyamfi-Bannerman, MD, of Columbia University Irving Medical Center in New York City, and colleagues.
The two infants who did have evidence of vertical transmission had indeterminate tests, suggesting they were infected at very low viral copy numbers, and neither had symptoms of COVID-19, they wrote in JAMA Pediatrics.
About three-quarters of mothers roomed-in with newborns, while six infants were separated from severely ill mothers who were in the ICU, and 19 infants were admitted to the neonatal ICU without contact with parents, Gyamfi-Bannerman and colleagues noted.
“This study endorses the benefits of rooming-in, establishing breastfeeding, and delaying bathing on newborn outcomes and suggests that separating mothers positive for SARS-CoV-2 and their newborns and avoiding direct breastfeeding may not be warranted to prevent SARS-CoV-2 transmission,” the authors wrote.
In the American Academy of Pediatrics (AAP) Perinatal COVID-19 Registry, data from more than 3,000 deliveries suggests about 2% of infants born to women who test positive for SARS-CoV-2 near the time of delivery have tested positive within 96 hours of birth.
Although there have been documented case reports of neonates with severe SARS-CoV-2 infection, this study and others confirm that most cases in young infants are asymptomatic or minimally symptomatic, commented David W. Kimberlin, MD, of the University of Alabama at Birmingham and Karen M. Puopolo, MD, PhD, of the University of Pennsylvania in Philadelphia, in an accompanying editorial.
In this study, 67% of mothers were asymptomatic and only identified to have SARS-CoV-2 viral RNA in routine testing. Also, only 55 of the 101 newborns had check-ups after discharge, with just six infants being tested for SARS-CoV-2 post-discharge, Kimberlin and Puopolo noted.
“Thus, the low risk of perinatal transmission observed in this study should be viewed within the context of the unclear timing of many of the maternal infections,” they wrote. “More importantly, the very low risk of postnatal infection should additionally be placed in the context of maternal/newborn physical separation… and the very careful infection control practices.”
Taken together, the findings suggest measures taken in the early stages of the pandemic to prevent transmission from mother to infant may have been overly conservative, Kimberlin and Puopolo noted.
This study collected data from mother-child pairs admitted from March 13 to April 24 to the NewYork-Presbyterian Morgan Stanley Children’s Hospital and the NewYork-Presbyterian Allen Hospital. All infants underwent SARS-CoV-2 testing on their first day of life and the majority obtained multiple tests within the next several days.
Overall, most women had asymptomatic or mild illness (90%). The median maternal age was 28.5, and 36 women had asthma, diabetes, chronic hypertension, or a hypertensive disorder of pregnancy. Also, 54 women had BMIs over 30.
Compared with moms with an asymptomatic or mild COVID-19 infection, newborns born to mothers with severe or critical COVID-19 were significantly more likely to be born about one week earlier (1.4-week difference, 95% CI 0.3-2.3, P=0.02), and they also had a higher incidence of hyperbilirubinemia requiring phototherapy (5/9% difference, 95% CI 0.8-36.1, P=0.04), the authors reported.
One of the newborns with evidence of vertical transmission was born via vaginal delivery and underwent testing on day 3 of life after mom started showing symptoms. The second newborn with evidence of vertical transmission was born via non-emergent cesarean delivery and mom was asymptomatic.
The findings were from a pandemic epicenter so they may not be generalizable to other communities, which is a limitation, the authors noted. Also, most women were infected in their third trimester in this study, they added.
Gyamfi-Bannerman disclosed support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Co-authors disclosed relevant relationships with UpToDate, Merck for Mothers, and GigaGen.
Kimberlin disclosed being an ex officio member of the AAP Committee on Infectious Diseases and being a member of the writing group for AAP Neonatal COVID guidance. Puopolo disclosed being a member of the AAP Committee on Fetus and Newborn and being a past member of the writing group for AAP Neonatal COVID guidance.