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By Nancy Lapid
(Reuters) – The following is a summary of some recent studies on COVID-19. This includes research results that warrant further studies to confirm the results and that have yet to be certified through peer review.
Epstein-Barr virus may play a role in some long-running COVID cases
COVID-19 can reactivate a common virus that lurks unseen in most people, and this effect could increase patients’ risk of certain long-lasting symptoms, according to preliminary results of a study. More than 90% of adults are infected with the Epstein-Barr virus (EBV). Most remained asymptomatic, but some developed mononucleosis as adolescents or young adults.
Among 280 patients with SARS-CoV-2 infections, including 208 with long COVID, the researchers found that four months after diagnosis, fatigue and problems with thinking and reasoning in study participants with immune cells in their blood, the signs of recent onset EBV showed reactivation occurred more frequently. However, these signs of reactivation were not linked to other long-standing COVID findings such as gastrointestinal or heart and lung problems. And EBV itself was not found in the patients’ blood, suggesting that reactivation is likely transient and occurring during acute COVID-19, Drs. Timothy Henrich from the University of California, San Francisco and colleagues at medRxiv https://www.medrxiv.org/content/10.1101/2022.06.21.22276660v1 prior to peer review.
The results don’t prove that EBV reactivation caused the patients’ symptoms, Henrich said. And even if that were the case, “there are likely many other causes of long COVID symptoms, such as: “Further studies in different tissues are urgently needed, as are studies that follow participants from the time of acute infection to months or years thereafter.”
SARS-CoV-2 can affect how blood sugar is processed by organs
Infection with the coronavirus affects the activity of several genes involved in the body’s chemistry, including blood sugar metabolism, and for the first time researchers have observed these effects not only in patients’ airways but elsewhere in the body.
Japanese researchers analyzed blood and tissue samples from patients with mild or severe COVID-19 and from healthy volunteers, and assessed the “expression” — or activity levels — of genes that control what’s known as the insulin/IGF signaling pathway, which in turn affects many bodily functions that are necessary for metabolism, growth and fertility. “The results were impressive,” study leader Iichiro Shimomura of Osaka University said in a statement. “Infection with SARS-CoV-2 affected the expression of components of the insulin/IGF signaling pathway in lung, liver, adipose tissue and pancreatic cells.” The resulting disturbances in blood glucose metabolism likely contribute to the effects of COVID-19 on the organs, said the researchers.
The changes, which they attribute in part to the immune system’s inflammatory response to the virus, were more pronounced in patients with severe COVID-19, they reported in the journal Metabolism https://www.metabolismjournal.com/article/S0026-0495 ( 22)00114-7/full text. In test-tube experiments, dexamethasone — known to benefit hospitalized patients with COVID-19 — helped mitigate the virus’ adverse effects on genes.
The new findings could provide a clue as to why some patients develop metabolic complications such as insulin resistance, hyperglycemia, hyperlipidemia and diabetes recurrence during or after COVID-19, the researchers said.
New data supports 5 days of isolation plus 5 days of masking
A new study supports current guidelines, which call for a five-day isolation period for COVID-19 infections, followed by five days of strict masking to prevent transmission of cases that remain culturally positive, researchers said.
Researchers at the Boston University School of Medicine collected daily nasal swabs for at least 10 days from 92 vaccinated college students and staff infected with the Delta or Omicron variants of the coronavirus for analysis with PCR and with the type of rapid antigen tests that are available to use at home. Among those young and otherwise healthy adults, just 17% tested positive after five days, and none were infectious more than 12 days after symptom onset, the researchers reported in Clinical Infectious Diseases https://academic.oup.com/cid/ advance-article/doi/10.1093/cid/ciac510/6614634. Results were similar regardless of variant or vaccine booster status, and negative rapid antigen tests were highly reliable, according to the report.
While rapid antigen testing “can ensure the absence of infectivity … a full 10 days is required to prevent transmission from the 17 percent of individuals who remain culture-positive after isolation,” said study leader Dr. Tara Bouton in a statement.
Click here for a Reuters graphic https://tmsnrt.rs/3c7R3Bl on vaccines in development.
(Reporting by Nancy Lapid; Editing by Bill Berkrot)
