Home Science Covid-19: French study confirms intrauterine transmission

Covid-19: French study confirms intrauterine transmission

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According to the scientist, the study shows that the transmission of the mother to the fetus occurs through the placenta and in the last weeks of pregnancy. The team followed a 20-year-old woman who was hospitalized, in early March, with a severe fever and cough. Blood tests and the collection of nasopharyngeal and vaginal samples confirmed that the young woman had been infected with the new coronavirus. Blood, nasopharyngeal and rectal samples taken from the baby one hour after delivery, three and 18 days after birth also showed positive results.

The highest load of Sars-CoV-2 was found in the placenta. “The virus passed from there through the umbilical cord to the baby, where it developed,” explains Daniel De Luca. According to the article, the placenta showed signs of acute and chronic inflammation, consistent with the severe systemic inflammatory state triggered in the mother as a result of Sars-CoV-2 infection. “It is important to note that the viral load is much higher in placental tissue than in amniotic fluid or maternal blood. This suggests the presence of the virus in placental cells, which is consistent with the inflammation findings seen in the histological examination ”, emphasize the authors.

Twenty-four hours after birth, the newborn had severe symptoms, including limb stiffness and damage to the cerebral nervous system. Neuroimaging analyzes indicated damage to the white matter, which, according to the scientists, may have been caused by vascular inflammation induced by the presence of Sars-CoV-2. “No other viral or bacterial infections have been found, and all other neonatal disorders potentially causing these clinical symptoms have been excluded,” they justify. The symptoms disappeared on their own, before doctors decided which treatment to take. Mother and son recovered from the infection and were discharged from the hospital.

Careful analysis

According to the authors, a congenital neonatal infection is considered proven when the virus is detected in the amniotic fluid collected before the rupture of the membranes for childbirth or in the blood collected early in the baby’s life. Thus, the case reported by them is the first to “fully qualify” for intrauterine transmission of Sars-CoV-2.

Previous studies have suggested this possibility of contagion, but the current one provides evidence of this phenomenon, according to Daniele De Luca. “It is necessary to analyze maternal blood, amniotic fluid, blood of the newborn, the placenta, etc. Gather all of these samples during an epidemic with emergencies in all directions not simple. that’s why it was suspicious, but without confirmation ”, he explains.

One of the studies, released last Friday, signaled this type of contagion through signs of Sars-CoV-2 infection in placental cells. It is the case of a girl who was born with 34 weeks of gestation, in a hospital in Texas, in the United States. Initially, she was treated in the neonatal intensive care unit (ICU) due to prematurity and suspected exposure to Sars-CoV-2.

The baby initially appeared healthy, with normal breathing and other vital signs. On the second day of life, however, he developed fever and relatively mild breathing problems and tested positive for covid-19. “The respiratory distress observed is unlikely to have been caused by prematurity, since it did not begin until the second day of life,” write the study authors, published in The Pediatric Infectious Disease Journal, the official journal of the European Society of Pediatric Infectious Diseases . The girl was treated with supplemental oxygen, but did not need mechanical ventilation. Tests of covid-19 remained positive for up to 14 days. On the 21st day of life, she and me returned home in good health.

Prevention boost

Analyzing the collected material, the researchers identified signs of inflammation of the tissues in the placenta and the presence of particles of the new coronavirus in fetal cells. According to them, the findings indicate that the infection had occurred intrauterine, not during or after birth. “We want to be very careful with the interpretation of these data, but now, an even more important time for pregnant women to protect themselves from covid-19”, warns, in a statement, Amanda S. Evans, a researcher at the University of Texas Southwestern Medical Center and one of the authors of the study.

The warning is also made by Marian Knight, professor of maternal and child health at Oxford University. According to the expert, of the thousands of cases of children born to mothers with covid-19, a little more than 2% tested positive for the virus, and almost none of the babies developed severe symptoms. Anyway, considering that it is an infection caused by a new virus, preventive measures should not be given up. “The main message for pregnant women continues to be to avoid infections through hand washing and social distance,” he says.

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