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COVID SCIENCE-Vaccines prove highly protective of healthcare workers; rapid tests unreliable in asymptomatic cases

March 24 (Reuters) - The following is a roundup of some of the latest scientific studies on the novel coronavirus and efforts to find treatments and vaccines for COVID-19, the illness caused by the virus.

Vaccines highly protective for healthcare workers

Data from healthcare workers at medical centers in the United States and Israel are confirming the effectiveness of both the Pfizer/BioNTech and Moderna vaccines against COVID-19, according to reports in The New England Journal of Medicine on Tuesday. Employee data from the University of California, San Diego and the University of California, Los Angeles health systems show that while COVID-19 cases surged in the general population, new detected infections among the staff dropped dramatically, beginning the second week after they received a first vaccine dose. Separately, in Texas, where hospital workers were vaccinated during the largest COVID-19 surge the region had seen, researchers found that 2.61% of unvaccinated employees tested positive versus 0.05% of fully-vaccinated employees. The Texas researchers saw a greater than 90% decrease in the number of employees in isolation or quarantine, which "preserved the workforce when it was most needed" during the surge, they said. In Jerusalem, with a high rate of COVID-19 in the community including many cases caused by the virus variant first identified in the UK, researchers found that the Pfizer vaccine achieved "a major reduction of new cases of COVID-19" among healthcare workers who received two doses. (bit.ly/3f7io8l; bit.ly/3d2dbvQ; bit.ly/3cclPso)

Point-of-care antigen tests unreliable in asymptomatic cases

"While-you-wait" tests for COVID-19 that detect proteins on the virus are better at diagnosing the disease in patients with symptoms than in those without symptoms, according to data pooled from 64 studies. The analysis, published on Wednesday by The Cochrane Library, found that on average, "antigen tests" correctly identified 72% of symptomatic COVID-19 cases but only 58% of cases in people without symptoms. The best-performing test - the SD Biosensor STANDARD Q - correctly identified the virus in 88% of symptomatic patients and in 69% of those with no symptoms. For screening purposes, among 10,000 people with no symptoms, where 50 people had COVID-19, this test would correctly identify 35, miss 15 cases, and incorrectly give positive results to 90 people who were not infected, the authors estimated. "Confirming a positive result from a rapid test with a RT-PCR test, particularly where cases of COVID-19 are low, may help avoid unnecessary quarantine," coauthor Jac Dinnes of the University of Birmingham in the UK said in a statement. "All antigen tests will miss some people with infection, so it is important to inform people who receive a negative test result that they may still be infected." Coauthor and Dinnes colleague Jon Deeks noted that repeated rapid antigen tests are being used to screen school pupils, teachers, and healthcare workers. "These testing policies have been implemented without any supporting real-world evidence," he said. (bit.ly/2NOCeKh)

Sleep problems, burnout may add to COVID-19 risk

People with sleep problems and daily burnout may be at higher risk for COVID-19, new research suggests. Healthcare workers who reported sleep problems in the year before the pandemic had 88% greater odds of contracting COVID-19 than those who slept well, according to research published in BMJ Nutrition Prevention & Health on Monday. Those who had suffered daily feelings of burnout were more than twice as likely to become infected with the coronavirus and roughly three times as likely to say their infection had been severe, compared to workers without burnout. Researchers surveyed 2,884 healthcare workers with heavy coronavirus exposure in Europe, the UK, and the United States, including 568 who said they had experienced COVID-19 symptoms or tested positive for the virus. They were more likely to have had trouble sleeping at night than those who had not been infected (24% vs 21%). In addition, more of them (5% vs 3%) reported at least three sleep problems, such as trouble falling asleep, staying asleep, or regularly needing sleeping pills. More COVID-19 survivors also reported suffering daily burnout in the previous year (5.5% vs 3%). Participants averaged 6 to 7 hours of sleep nightly. After accounting for other risk factors, every extra hour of nighttime sleep in the previous year was associated with 12% lower odds of COVID-19, researchers reported. (bit.ly/3tWWxot)

Open tmsnrt.rs/3c7R3Bl in an external browser for a Reuters graphic on vaccines in development.

Reporting by Nancy Lapid; Additional reporting by Gene Emery; Editing by Bill Berkrot

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