The Swedish case: How did the virus mutate before the baby was born?

Doctors in Sweden encountered a rare case when a pregnant woman came in complaining of severe abdominal pain. They discovered that the fetus had a slow heartbeat and lacked oxygen, so they immediately performed a cesarean section and saved the baby.

Because the woman developed a dry cough and fever the day before she was admitted to the hospital, the medical staff ran a coronavirus test on her, which came back positive. At the same time, they did not immediately test the newborn for coronavirus, since he had no contact with the mother, and they did it after two days, as the rules require. The analysis was positive, and after ruling out the possibility that the child could have been infected by someone from the medical staff, the doctors concluded that the baby was infected in the mother’s womb.

In addition, it was found that the child had developed a new mutation, called A107G, in addition to the virus transmitted by the mother. However, the mutation has only just begun to manifest itself: nearly a third of the virus particles from the initial analysis still had the maternal genome. Doctors say this is the first known case of a genetic mutation of the coronavirus that is acquired before birth and undergoes genetic changes in the first five days of the baby’s life. According to the researchers, this could have occurred as a result of exposure to an external environment different from the mother’s womb.

Fortunately, the mother recovered quickly and was discharged from the hospital four days after giving birth. The child, who had a mild form of the disease, was also able to recover on his own because his immune system quickly produced the antibodies needed to fight the virus.

Although cases of mother-to-newborn transmission of coronavirus are quite rare, and complications when coronavirus causes fetal hypoxia are even rarer, experts say the current approach to pregnant women with coronavirus may need to be reconsidered and they may need to be placed in a higher-risk group. The authors of the study draw two conclusions from this case.