Strong Evidence That CV19 is Transmitted in the Wombby Laura Driver
A baby girl who was born with coronavirus is the "strongest evidence yet" that the virus is transmitted in the womb, experts say.
The baby’s mum, from Texas, US, had been diagnosed with Covid-19 before her waters broke at 34 weeks and she gave birth prematurely. Her baby was taken to intensive care and initially appeared healthy, but the next day she had developed a fever and breathing difficulties. The baby tested positive for SARS-CoV-2 - the infection that causes Covid-19 - at 24 and 48 hours after birth. She was treated with supplemental oxygen for several days but did not need mechanical ventilation. Tests for coronavirus continued to come back positive for two weeks, but at 21 days, mum and baby were sent home in good condition.
The medics, from the University of Texas Southwestern Medical Center in Dallas, say they are the first to document intrauterine, or 'in the womb', transmission of coronavirus from an infected mother to her infant. Their case report, lead by Dr Julide Sisman, was published in The Paediatric Infectious Disease Journal by Wolters Kluwer Health on Friday.
Dr Amanda S. Evans, one of the lead authors of the new study, said: "Numerous infants have now been delivered to pregnant women diagnosed with SARS-CoV-2, with the majority of these infants without respiratory illness or positive molecular evidence for SARS-CoV-2.
"Our study is the first to document intrauterine transmission of the infection during pregnancy, based on immunohistochemical and ultrastructural evidence of SARS-CoV-2 infection in the fetal cells of the placenta."
The authors report that the baby girl's mother, who also had type 2 diabetes, had been diagnosed with Covid-19 while pregnant. She gave birth at 34 weeks after suffering premature rupture of the membranes, which is the amniotic sac that keeps the baby protected inside the womb. The baby was also born "large for gestation age" - an important complication of infants of diabetic mothers, they write.
They took her to the neonatal ICU due to prematurity and possible exposure to Covid. The infant appeared initially healthy, with normal breathing and other vital signs. But on the second day of life, she developed fever and relatively mild breathing problems.
Writing in a case report, the doctors said: "It is unlikely that the respiratory distress observed in this infant was due to prematurity since it did not start until the second day of life."
She first tested positive for Covid 24 hours after birth and continued to show the virus in her system for 14 days. The researchers examined the placenta, which showed signs of tissue inflammation. But more intricate tests of the fetal cells revealed the presence of coronavirus particles and a protein specific for Covid-19.
Together, these findings confirmed that the infection was transmitted in the womb, rather than during or after birth, according to the report.
Dr Sisman said that although data on Covid-19 remains very limited, "intrauterine transmission of SARS-CoV-2 appears to be a rare event". The team also highlighted urgent areas for further research, including the mechanisms and risk factors of transmission via the womb, as well as the outcomes of congenital Covid-19 in infants. "We wanted to be very careful of our interpretation of this data, but now is an even more important time for pregnant women to protect themselves from Covid-19," Dr Evans added.
Two additional case reports in the journal also describe "vertical" transmission of the virus from mother to infant which happened under different circumstances. Dr George K. Siberry, of the US Agency for International Development, said the three cases combined highlight the important but difficult distinction between virus transmission occurring before or during/after delivery. Dr Siberry said: "As these cases illustrate, evaluation for vertical - and especially intrauterine - SARS-CoV-2 infection can be challenging, and assessment is often limited by lack of optimal testing of appropriate specimens obtained at specific timepoints."