Third of newborns with Covid infected before or during birth – study

By Ian Sample Science editor

Nearly a third of coronavirus infections in newborn babies are picked up in the womb or from the mother during labour, a review of reported cases has found.

While Covid-19 is rare in newborns, doctors have been keen to understand the potential risks that babies face should tests reveal they have the infection soon after birth.

Doctors in France examined 176 published cases of neonatal coronavirus infections in which the infants tested positive at least once or were found to have antibodies against the virus.

Most of the babies, about 70%, were infected in hospital where the mother, medical staff, other patients, family members and visitors all posed a potential infection risk. The rest of the infections were passed on directly from the mother before or during birth.

Daniele De Luca, medical director of paediatrics and neonatal critical care at the Antoine Béclère hospital in Paris, said that despite being rare, it was important for doctors to be aware that newborns can be born with the virus or contract it while in hospital. “At the beginning of the pandemic, some argued that this would never touch babies. It’s rare, but it does exist,” he said.

The review, published in Nature Communications, found that half of the newborns with coronavirus were asymptomatic. Of those that went on to develop symptoms, 64% had abnormal lung scans, 52% had breathing problems, 44% had a fever, and 36% had difficulties with feeding, diarrhoea and vomiting.

A small number of the babies, about 18% who fell ill with the virus, developed neurological symptoms ranging from irritability and lethargy to problems with muscle tone that made the limbs either floppy or too stiff.

The cases in the review may be at the worse end of the spectrum for newborns with Covid-19, since doctors are more likely to report worrying cases and journals are more likely to publish them. De Luca said that even among those reviewed, very few had severe disease and nearly all recovered. Three children included in the review died of unrelated causes.

After examining how the newborns became infected and what symptoms they developed, the doctors looked at whether mothers with Covid-19 passed the infection on through close contact or breastfeeding. The doctors found no extra risk from breastfeeding, but if the mother was infectious, the chances of passing the virus on to her baby in the first few days were nearly five times higher than if mother and baby were kept apart.

“We know that keeping the mother and baby together has a lot of advantages, but if the mother is symptomatic, it would be better for some days to be cautious,” De Luca said, adding that the mother may want to express milk so it can be given by a family member until she is no longer infectious. “If they cannot be separated, and in some cases it is impossible, the mother should try to be extra-careful while she is symptomatic, and if possible use PPE and hand gel to reduce the risk of transmission.”

Dr Helen Mactier, President of the British Association of Perinatal Medicine said: “This paper provides reassuring evidence to add to what we know already. Neonatal Covid-19 is very rare, and generally a mild illness. There is no reason to amend current advice that mother and baby can stay together unless there is a medical reason for the baby to be admitted to a neonatal unit. Really importantly, this paper provides good evidence of the safety of breastfeeding, which should of course be encouraged.”