News briefs

COVID‐19 during pregnancy: increased risk of severe illness

Coronavirus disease 2019 (COVID‐19) infection in pregnant women is associated with increased risk of adverse outcomes compared with women who are not pregnant, according to a review published in JACC: Advances. Cardiovascular complications include heart attack, arrythmias, heart failure and long‐haul symptoms that may be difficult to distinguish from other cardiac complications of pregnancy and require the cardiovascular care team to be vigilant when assessing pregnant women with COVID‐19. The Centers for Disease Control and Prevention (CDC) found pregnant women are at increased risk of adverse outcomes with COVID‐19, including severe infection (10%), intensive care unit admission (4%), mechanical ventilation (3%), and use of extracorporeal membrane oxygenation haemodynamic support (0.2%), compared with non‐pregnant women of reproductive age. Additionally, pregnant patients who were of increased maternal age, high body mass index or had other pre‐existing conditions, such as chronic hypertension, pre‐eclampsia and pre‐existing diabetes, were at even higher risk for severe infection. When compared with pregnant women without COVID‐19, pregnant patients with COVID‐19 were at higher risk for pre‐term birth and stillbirth. Overall, 33% of infants born to patients with COVID‐19 were admitted to the neonatal intensive care unit. No other differences have been found for perinatal outcomes. According to the authors, a reason for increased risk of cardiovascular complications is the low vaccination rate in pregnant women compared with other groups. In a recent study of over 130 000 pregnant people, over three‐quarters of those requiring hospital admission, most patients requiring critical care, and all fetal deaths occurred in unvaccinated compared with vaccinated women. The authors suggest management of cardiac complications in pregnant patients with COVID‐19 requires the creation of a “pregnancy heart team” to optimise care, which may include providers comfortable with high risk pregnancy, obstetric anaesthesia, cardiology, critical care and neonatal care, depending on the nature of the complication, stage of pregnancy and severity of infection.

https://www.sciencedirect.com/science/article/pii/S2772963X22000618?via%3Dihub

Mystery gene that helps mice survive virus infections

Researchers from UNSW Sydney have discovered that a particular transposable element, or jumping gene, in the genome has a profound effect on the immune response to virus infection. The findings in mice, published in Nature, provide new information about how the immune system is regulated, and have potential ramifications for the treatment of virus infections that can lead to an overactive immune response. Up to two‐thirds of a mammal’s genome are obtained from transposable elements. But apart from some consensus that transposable elements negatively or positively affect gene transcription — a fundamental process in our genome where DNA gets copied into RNA — scientists do not fully understand what these jumping genes do. The authors say to really understand their function, researchers needed to observe what happens when they remove one of these transposable elements from an animal. This particular transposable element is located near one of the most highly expressed genes following virus infection, in the Schlafen gene family. There are ten Schlafen genes in mice and seven in humans and they are critically important as they encourage cell proliferation in response to viruses and inhibit virus replication. After knocking out one of the transposable elements — called Lx9c11 — from mice, the researchers infected the animals with Coxsackievirus B4, a virus that largely affects the pancreas and some other tissues. But instead of usually clearing the virus, the mice who had lost the Lx9c11 element died. The researchers discovered the Lx9c11 deficient mice had an exaggerated immune response, similar to what is rarely experienced by patients with influenza and more commonly experienced by people with severe COVID‐19. And the data indicated that the lethality was host induced. When they put the transposable element back into other still‐living mice that had been infected with Coxsackievirus B4, those mice survived the infection.

https://www.nature.com/articles/s41586‐022‐05054‐9