Genes may explain critical COVID-19 in young, healthy adults

A gene that helps the coronavirus reproduce itself might contribute to life-threatening COVID-19 in young, otherwise healthy people, new findings suggest.

French researchers studied 72 hospitalized COVID-19 patients under age 50, including 47 who were critically ill and 25 with non-critical illness, plus 22 healthy volunteers. None of the patients had any of the chronic conditions known to increase the risk for poor outcomes, such as heart disease or diabetes.

Genetic analysis identified five genes that were significantly “upregulated,” or more active, in the patients with critical illness, of which the most frequent was a gene called ADAM9. As reported on Tuesday in Science Translational Medicine, the researchers saw the same genetic pattern in a separate group of 154 COVID-19 patients, including 81 who were critically ill.

Later, in lab experiments using human lung cells infected with the coronavirus, they found that blocking the activity of the ADAM9 gene made it harder for the virus to make copies of itself. More research is needed, they say, to confirm their findings and to determine whether it would be worthwhile to develop treatments to block ADAM9.

Pregnant women get sub-par benefit from first vaccine dose

Women who get the first dose of an mRNA COVID-19 vaccine while pregnant or breastfeeding need the second dose to bring their protective benefit up to normal, according to a new study. Researchers compared immune responses to the mRNA vaccines from Moderna or Pfizer and partner BioNTech in 84 pregnant women, 31 breastfeeding women, and 16 similarly-aged nonpregnant, non-lactating women.

After the first shot, everyone developed antibodies against the coronavirus. But antibody levels were lower in women who were pregnant or breastfeeding. Other features of the immune response also lagged in the pregnant and lactating women after the first dose but “caught up” to normal after the second shot. In a report published last week inScience Translational Medicine, the researchers explained that in order for a mother’s body to nurture the fetus, “substantial immunological changes occur throughout pregnancy.”

The new findings suggest that pregnancy alters the immune system’s response to the vaccine. Given that pregnant women are highly vulnerable to complications from COVID-19, “there is a critical need” for them to get the second dose on schedule, the researchers said.