Covid-19 thrice as deadly as seasonal flu, oximeters less reliable on Black patients: Study

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.

Covid-19 far more deadly than seasonal flu

Covid-19 is three times more deadly than seasonal influenza, according to researchers in France who compared 89,530 patients hospitalized with Covid-19 early this year with 45,819 patients hospitalized with flu between December 2018 and February 2019. The death rate was 16.9% vs 5.8%, which is "particularly striking when reminded that the 2018/2019 flu season had been the worst in the past five years in France in terms of number of deaths," Dr. Catherine Quantin, from Dijon University Hospital, said in a news release. More patients with Covid-19 landed in intensive care units (16.3% vs 10.8%) and the average ICU stay was nearly twice as long (15 days vs 8 days), her team reported on Thursday in The Lancet Respiratory Medicine. Covid-19 patients were also more likely to need mechanical ventilation and to suffer lung failure. In another study published on Wednesday in The BMJ, U.S. researchers found people being hospitalized for Covid-19 carried higher risks of organ failure and death, and increased health resource use, compared to people hospitalized for the flu. 

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Oxygen-monitoring devices less reliable in Black patients

Covid-19 can cause blood oxygen levels to fall to dangerously low levels, and devices used to monitor these levels are far less reliable in Black patients than in white patients, a large study found. So-called pulse oximeters clip onto a fingertip and pass red and infrared light through the skin to gauge oxygen levels in the blood, which darkens when levels drop. Because pulse oximeters were mostly tested on whites when they were developed, they are calibrated for people with light skin. Among 1,609 patients studied this year at the University of Michigan Hospital in Ann Arbor, the devices missed low oxygen levels in 11.7% of Black patients compared to 3.6% of white patients. When the researchers studied another 8,392 patients treated at 178 intensive-care units in 2014-2015, they found pulse oximeters missed low oxygen levels in 17.0% of Blacks versus 6.2% of whites. "Given the widespread use of pulse oximetry for medical decision-making, these findings have some major implications, especially during the current Covid-19 pandemic," the researchers warned on Wednesday in The New England Journal of Medicine. "Reliance on pulse oximetry to triage patients and adjust supplemental oxygen levels may place Black patients at increased risk." 

Minority Covid-19 patients may benefit from tocilizumab

Among mostly non-white patients hospitalized with Covid-19 pneumonia, Roche's arthritis drug Actemra, also known as tocilizumab, reduced the odds of needing mechanical ventilation or dying. Among the 389 volunteers in a study, the combined risk of those events was 12% in patients randomly assigned to receive tocilizumab in addition to standard care, versus 19% in those who received a placebo. Looking only at the risk of death, however, rates in the two groups were similar, researchers reported on Thursday in The New England Journal of Medicine. Tocilizumab also did not hasten patients' discharge from the hospital or the time it took for their medical status to improve. Previous studies did not focus on racial or ethnic minorities and yielded mixed results. Earlier this month, a different team of doctors reported that the drug reduced patients' risk of dying in the hospital, but the difference was not statistically significant. The Infectious Diseases Society of America currently does not recommend the routine use of tocilizumab in hospitalized patients.

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