Researchers on Tuesday reported strong evidence that the coronavirus can be transmitted from a pregnant woman to a fetus.
A baby born in a Paris hospital in March to a mother with Covid-19 tested positive for the virus and developed symptoms of inflammation in his brain, said Dr. Daniele De Luca, who led the research team and is chief of the division of pediatrics and neonatal critical care at Paris-Saclay University Hospitals. The baby, now more than 3 months old, recovered without treatment and is “very much improved, almost clinically normal,” Dr. De Luca said, adding that the mother, who needed oxygen during the delivery, is healthy.
Dr. De Luca said the virus appeared to have been transmitted through the placenta of the 23-year-old mother.
Since the pandemic began, there have been isolated cases of newborns who have tested positive for the coronavirus, but there has not been enough evidence to rule out the possibility that the infants became infected by the mother after they were born, experts said. A recently published case in Texas, of a newborn who tested positive for Covid-19 and had mild respiratory symptoms, provided more convincing evidence that transmission of the virus during pregnancy can occur.
In the Paris case, Dr. De Luca said, the team was able to test the placenta, amniotic fluid, cord blood, and the mother’s and baby’s blood.
The testing indicated that “the virus reaches the placenta and replicates there,” Dr. De Luca said. It can then be transmitted to a fetus, which “can get infected and have symptoms similar to adult Covid-19 patients.”
A study of the case was published on Tuesday in the journal Nature Communications.
Dr. Yoel Sadovsky, executive director of Magee-Womens Research Institute at the University of Pittsburgh, who was not involved in the study, said he thought the claim of placental transmission was “fairly convincing.” He said the relatively high levels of the coronavirus found in the placenta and the rising levels of virus in the baby and the evidence of placental inflammation, along with the baby’s symptoms, “are all consistent with SARS-CoV-2 infection.”
Still, Dr. Sadovsky said, it is important to note that cases of possible coronavirus transmission in utero appear to be extremely rare. With other viruses, including Zika and rubella, placental infection and transmission is much more common, he said. With the coronavirus, he said, “we are trying to understand the opposite — what underlies the relative protection of the fetus and the placenta?”
Another study published on Tuesday in eLife, an online research journal, may help answer that question. It found that while cells in the placenta had many of the receptor proteins that allow viruses to propagate, there was evidence of only “negligible” amounts of a key cell surface receptor and an enzyme that are known to be involved in allowing the coronavirus to enter cells and replicate. The study was led by Dr. Robert Romero, chief of the perinatology research branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
The report from doctors in Paris said that the woman was 35 weeks pregnant when she came to the hospital with a fever and a cough that she developed a couple of days earlier in what was an otherwise healthy pregnancy. She tested positive for the coronavirus. After three days, fetal heart monitoring indicated signs of distress, and the baby was delivered by emergency cesarean section.
The Coronavirus Outbreak ›
Frequently Asked Questions
Updated July 15, 2020
Is the coronavirus airborne?
- The coronavirus can stay aloft for hours in tiny droplets in stagnant air, infecting people as they inhale, mounting scientific evidence suggests. This risk is highest in crowded indoor spaces with poor ventilation, and may help explain super-spreading events reported in meatpacking plants, churches and restaurants. It’s unclear how often the virus is spread via these tiny droplets, or aerosols, compared with larger droplets that are expelled when a sick person coughs or sneezes, or transmitted through contact with contaminated surfaces, said Linsey Marr, an aerosol expert at Virginia Tech. Aerosols are released even when a person without symptoms exhales, talks or sings, according to Dr. Marr and more than 200 other experts, who have outlined the evidence in an open letter to the World Health Organization.
What are the symptoms of coronavirus?
What’s the best material for a mask?
Is it harder to exercise while wearing a mask?
- A commentary published this month on the website of the British Journal of Sports Medicine points out that covering your face during exercise “comes with issues of potential breathing restriction and discomfort” and requires “balancing benefits versus possible adverse events.” Masks do alter exercise, says Cedric X. Bryant, the president and chief science officer of the American Council on Exercise, a nonprofit organization that funds exercise research and certifies fitness professionals. “In my personal experience,” he says, “heart rates are higher at the same relative intensity when you wear a mask.” Some people also could experience lightheadedness during familiar workouts while masked, says Len Kravitz, a professor of exercise science at the University of New Mexico.
I’ve heard about a treatment called dexamethasone. Does it work?
- The steroid, dexamethasone, is the first treatment shown to reduce mortality in severely ill patients, according to scientists in Britain. The drug appears to reduce inflammation caused by the immune system, protecting the tissues. In the study, dexamethasone reduced deaths of patients on ventilators by one-third, and deaths of patients on oxygen by one-fifth.
What is pandemic paid leave?
- The coronavirus emergency relief package gives many American workers paid leave if they need to take time off because of the virus. It gives qualified workers two weeks of paid sick leave if they are ill, quarantined or seeking diagnosis or preventive care for coronavirus, or if they are caring for sick family members. It gives 12 weeks of paid leave to people caring for children whose schools are closed or whose child care provider is unavailable because of the coronavirus. It is the first time the United States has had widespread federally mandated paid leave, and includes people who don’t typically get such benefits, like part-time and gig economy workers. But the measure excludes at least half of private-sector workers, including those at the country’s largest employers, and gives small employers significant leeway to deny leave.
Does asymptomatic transmission of Covid-19 happen?
- So far, the evidence seems to show it does. A widely cited paper published in April suggests that people are most infectious about two days before the onset of coronavirus symptoms and estimated that 44 percent of new infections were a result of transmission from people who were not yet showing symptoms. Recently, a top expert at the World Health Organization stated that transmission of the coronavirus by people who did not have symptoms was “very rare,” but she later walked back that statement.
What’s the risk of catching coronavirus from a surface?
- Touching contaminated objects and then infecting ourselves with the germs is not typically how the virus spreads. But it can happen. A number of studies of flu, rhinovirus, coronavirus and other microbes have shown that respiratory illnesses, including the new coronavirus, can spread by touching contaminated surfaces, particularly in places like day care centers, offices and hospitals. But a long chain of events has to happen for the disease to spread that way. The best way to protect yourself from coronavirus — whether it’s surface transmission or close human contact — is still social distancing, washing your hands, not touching your face and wearing masks.
How does blood type influence coronavirus?
- A study by European scientists is the first to document a strong statistical link between genetic variations and Covid-19, the illness caused by the coronavirus. Having Type A blood was linked to a 50 percent increase in the likelihood that a patient would need to get oxygen or to go on a ventilator, according to the new study.
How can I protect myself while flying?
- If air travel is unavoidable, there are some steps you can take to protect yourself. Most important: Wash your hands often, and stop touching your face. If possible, choose a window seat. A study from Emory University found that during flu season, the safest place to sit on a plane is by a window, as people sitting in window seats had less contact with potentially sick people. Disinfect hard surfaces. When you get to your seat and your hands are clean, use disinfecting wipes to clean the hard surfaces at your seat like the head and arm rest, the seatbelt buckle, the remote, screen, seat back pocket and the tray table. If the seat is hard and nonporous or leather or pleather, you can wipe that down, too. (Using wipes on upholstered seats could lead to a wet seat and spreading of germs rather than killing them.)
What should I do if I feel sick?
The baby was placed in the neonatal intensive care unit and was connected to a ventilator for about six hours, the authors reported. He seemed to be doing well, but on his third day he became irritable, had trouble feeding and was experiencing muscle spasms and rigidity.
A brain scan showed some injury to the white matter, which Dr. De Luca said resembled symptoms of meningitis or inflammation in the brain. He tested negative for other viruses or bacterial infections that could have caused such symptoms, while tests of his blood and fluid from his lungs were positive for coronavirus infection, the authors said. The baby gradually recovered and left the hospital after 18 days.
The authors said that the highest levels of the coronavirus were found in the placenta, higher than those in the amniotic fluid and in the blood of the mother and baby, which Dr. De Luca said suggested that the virus might be able to replicate in placental cells.
Dr. De Luca, who is also the president-elect of the European Society for Pediatric and Neonatal Intensive Care, said his team was analyzing other suspected cases of placental transmission of the coronavirus.
“This will be helpful for clinicians and policymakers in order to manage pregnant women, check neonates and reduce the risk of viral transmission from mothers to neonates,” he said, adding, “The good news is that the baby recovered spontaneously and gradually despite all this, and this confirms that the disease is milder in early infancy.”