In this week's roundup, the latest scientific research on the coronavirus and efforts to find treatments and vaccines suggest that the placenta may have a way to protect itself and the fetus from COVID-19 infection, and that the common protein helps the virus unlock a gateway into cells.
COVID-19 patients face risks after hospital discharge
People face substantially higher risks of health problems in the months after being discharged from hospital following a bout of the coronavirus, researchers in England found.
Comparing 24,673 COVID-19 patients who survived at least a week after hospital discharge and 123,362 similarly aged people in the general population, they found the COVID-19 survivors had twice the risk of hospital admission or death during the next 10 months. Compared with 16,058 patients who had been hospitalized for influenza, the COVID-19 patients were 37% more likely to be readmitted or die due to their initial infection or other lower respiratory tract infections, and 37% more likely to experience cognitive-related admission or death, researchers reported in PLOS Medicine. COVID-19 patients with dementia who survived hospitalization were at particularly high risk for death in the months afterward, according to the report.
"Large numbers of people have been hospitalized with COVID-19 ... and the raised risks of death and readmission ... could significantly impact public health and resources," the researchers wrote. "Risks might be minimized or mitigated by increasing monitoring of patients in the months following hospital discharge, and greater awareness among patients and clinicians of potential problems."
Heart returns to normal after rare post-COVID illness in kids
In children who develop the rare but life-threatening COVID-19-related multisystem inflammatory syndrome (MIS-C), heart function begins to recover within a week after diagnosis and returns to normal within three months, a new study suggests.
With onset about four-to-six weeks after exposure to the coronavirus, MIS-C can cause inflammation in the heart, lungs, kidneys and gastrointestinal organs. Roughly four in five cases involve the child's left ventricle, which pumps blood to the rest of the body. Researchers studied 60 children hospitalized with MIS-C – 70% of whom had evidence of heart muscle injury – and 60 healthy children with normal hearts. Echocardiography and magnetic resonance imaging showed that all abnormalities in the hospitalized children "recovered quickly within the first week, followed by continued improvement and complete normalization by three months," researchers reported in the Journal of the American Heart Association. In half of the children, MIS-C-related heart function changes were gone within six days, they said.
The study did not evaluate the course of other after-effects. Still, said Dr. Anirban Banerjee of the Children's Hospital of Philadelphia in a statement, "Recovery among these children was excellent." He added that the findings have important implications for managing children with MIS-C. "Our findings may also provide guidance for a gradual return to playing sports after cardiac clearance three to four months later," he added.
Common protein helps virus unlock gateway into cells
When the SARS-CoV-2 spike breaks into cells via a "gateway" protein on cell surfaces called ACE2, a second cell-surface protein called vimentin facilitates the process, possibly by serving as a bridge between the virus and ACE2, new research suggests.
Using sophisticated analytical chemistry techniques, the researchers observed that vimentin attaches itself to the spike protein on the surface of the coronavirus. Based on their findings, they believe it might also attach itself to the ACE2 protein. In test tube experiments, they saw that when both vimentin and ACE2 are present, entry of the virus into the cells that line the blood vessels increases. They also found that depletion of vimentin significantly reduces SARS-CoV-2 infection of human cells, according to a report published in PNAS. Study co-author Nader Rahimi of Boston University School of Medicine said his team found that a monoclonal antibody developed by Abcam Plc blocked vimentin from binding to the virus, in turn keeping the virus from entering the cells.
Vimentin is also found on cells lining the heart, the air sacs of the lungs and the nose, the researchers noted. "Establishing the full range of the involvement of vimentin in viral entry and infection will require further investigations," the researchers said in a statement. They said they hope their findings will lead to new antiviral drugs that keep both ACE2 and vimentin from interacting with the coronavirus.
Placenta may shed proteins to keep virus out
The placenta may have a way to protect itself and the fetus from infection with the coronavirus, a small study suggests.
Researchers studied 24 women who gave birth between July 2020 and April 2021. Eight had symptomatic COVID-19 in the second trimester, eight were sick from the virus in the third trimester, and eight were not infected during pregnancy. When COVID-19 occurred in pregnancy, particularly during the third trimester, placenta cells appeared to "shed" a surface protein called ACE2 that the virus uses to break into cells and infect them, leaving fewer gateways for entry. Women who had COVID-19 in the third trimester had high levels of an enzyme called ADAM17 that is known to help ACE2 release itself from the cell surface, the researchers reported in The American Journal of Pathology.
The placenta may be sensing the maternal COVID-19 infection "and possibly putting in place this mechanism to help shed off ACE2, prevent SARS-CoV-2 from invading the placenta and passing on to the fetus," said Elizabeth Taglauer of Boston Medical Center. Earlier studies have shown that placental cells become infected in only about 7% to 20% of pregnancies where the mother has COVID-19, Taglauer highlighted. When the virus does somehow get into the placenta, it rarely reaches the fetus, she added. Her team plans further studies of "protection pathways" that may be keeping the virus out of placental cells and away from fetal blood vessels.
COVID-19 vaccines safe in rheumatic, musculoskeletal diseases
COVID-19 vaccines appear to be safe for people with rheumatic and musculoskeletal diseases and are likely to trigger flares – a sudden worsening of symptoms – in less than 5% of cases, researchers have found.
The findings were based on data from 5,121 patients in 30 countries. Severe flares occurred in fewer than 1% of patients after vaccination, they found. Overall, flares were more likely to occur in patients with active disease, according to a report published in Annals of the Rheumatic Diseases. "However, it is important to note that flares can occur as part of the ... disease, and the observed percentages of flares would be compatible with the natural history of the disease rather than necessarily caused by vaccines against SARS-CoV-2," said Dr. Pedro Machado of University College London. The average study participant was 72 years old, and most were women. Many had inflammatory joint diseases, connective tissue diseases or vasculitis and were receiving various combinations of disease-modifying antirheumatic drugs, immunosuppressants and other medications.
Most had received the Pfizer-BioNTech COVID-19 vaccine (70%), followed by shots from AstraZeneca (17%) and Moderna (8%). "Our findings should provide reassurance to rheumatologists, other health professionals and vaccine recipients, and promote confidence in the safety of COVID-19 vaccination in people with inflammatory rheumatic diseases," Dr. Machado said.
Peer-review does not lead to major changes in 'preprints'
Two studies published on Tuesday in PLoS Biology suggest that papers posted on so-called preprint servers before undergoing formal peer review do not change significantly before publication in medical journals.
One study compared more than 180 reports posted during the first four months of the pandemic on the preprint servers medRxiv and bioRxiv to the versions eventually published in peer-reviewed journals. Roughly 83% of COVID-19-related papers and 93% of non-COVID-19-related papers did not change from their preprint to final published versions, they found. When the researchers did identify changes, in the majority of cases those changes did not qualitatively change the conclusions of the paper, they said.
The other study used machine learning to analyze the relationships between nearly 18,000 preprints on the bioRxiv server and their published versions. Most manuscripts had only modest changes in wording during the peer-review and publication process, the researchers found.