CORRECTED-COVID SCIENCE – Breakthrough infections can lead to long-term COVID; genes may explain critical illness in young, healthy adults

(Corrects publication or publication dates for studies)

By Nancy Lapid

Oct. 27 (Reuters) – The following is a summary of some recent studies of COVID-19. They include research that warrants further study to confirm the findings and has yet to be certified by peer review.

Breakthrough infections can lead to long-term COVID

The ongoing syndrome of COVID-19 aftereffects, known as long-term COVID, can develop after “breakthrough” infections in vaccinated people, a new study shows. Researchers from the University of Oxford in the UK reviewed data from nearly 20,000 US COVID-19 patients, half of whom had been vaccinated. Compared to unvaccinated patients, fully vaccinated individuals — especially those under the age of 60 — had a lower risk of death and serious complications such as lung failure, ventilator support, ICU admission, life-threatening blood clots, seizures and psychosis. “On the other hand,” the research team reported on medRxiv on Tuesday prior to peer review, “prior vaccination does not appear to protect against several previously documented outcomes of COVID-19 such as long-term COVID features, arrhythmia, joint pain, type 2 diabetes, liver disease, sleep disorders, and mood and anxiety disorders.” The absence of protection against long-term COVID “is concerning given the high incidence and burden” of these enduring problems, she added.

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

A gene that helps the coronavirus reproduce itself may contribute to life-threatening COVID-19 in young, otherwise healthy people, new findings suggest. French researchers studied 72 hospitalized COVID-19 patients under the age of 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 of 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, the most common of which was a gene called ADAM9. As reported 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 with human lung cells infected with the coronavirus, they found that blocking the activity of the ADAM9 gene made it more difficult for the virus to make copies of itself. More research is needed, they say, to confirm their findings and determine whether it is worth developing treatments to block ADAM9.

Pregnant women do not benefit from the first vaccine dose

According to a new study, women who receive the first dose of an mRNA COVID-19 vaccine while pregnant or breast-feeding need the second dose to boost their protective benefit. Researchers compared immune responses to the mRNA vaccines from Moderna Inc or Pfizer Inc and partner BioNTech SE in 84 pregnant women, 31 breastfeeding women, and 16 age-matched non-pregnant, non-lactating women. After the first injection, 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 pregnant and lactating women after the first dose, but “catching up” after the second injection. In a report published last week in Science Translational Medicine, the researchers explained that in order for a mother’s body to nourish the fetus, “significant immunological changes occur during 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.

Coronavirus appears to infect fat cells

Obesity is a known risk factor for more severe COVID-19. One likely reason may be that the virus can infect fat cells, researchers have found. In lab experiments and in autopsies of patients who died from COVID-19, they found that the virus infects two types of cells in adipose tissue: mature fat cells called adipocytes and immune cells called macrophages. “Infection of fat cells led to a marked inflammatory response, consistent with the type of immune response seen in severe cases of COVID-19,” said Dr. Catherine Blish of Stanford University School of Medicine, whose team reported the findings on bioRxiv. on Monday prior to peer review. “These data suggest that infection of adipose tissue and the associated inflammatory response may be one of the reasons obese individuals do so poorly when infected with SARS-CoV-2,” she said.

Click for an image from Reuters on vaccines in development.

(Reporting by Nancy Lapid; editing by Bill Berkrot)

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