Studies explore asymptomatic COVID-19 cases, racial inequities

Studies explore asymptomatic COVID-19 cases, racial inequities Blacks and Hispanics were 1.9 and 1.8 times, respectively, more likely than whites to test positive. CIDRAP

Today, PLOS Medicine published two large COVID-19 studies, one a meta-analysis of 79 international studies showing that most infected patients eventually have symptoms, and the other a study of 5.8 million US Department of Veterans Affairs patients revealing that blacks and Hispanics were more likely to be infected—but not to die within 30 days—than whites.

The first study, by researchers at the University of Bern in Switzerland, consisted of a systematic review and meta-analysis of COVID-19 literature from March to June and an analysis of 79 studies involving 6,616 people in 19 countries or territories, of whom 1,287 were classified as asymptomatic.

The investigators found that only 20% of coronavirus patients reported no symptoms at follow-up, and these patients appeared less likely than those with symptoms to infect others (relative risk, 0.35). Modeling studies that were included suggested that people with presymptomatic infections were more infectious than those with no symptoms. ...

"The findings of this systematic review of publications early in the pandemic suggests that most SARS-CoV-2 infections are not asymptomatic throughout the course of infection," the authors said in a PLOS news release. "The contribution of presymptomatic and asymptomatic infections to overall SARS-CoV-2 transmission means that combination prevention measures, with enhanced hand and respiratory hygiene, testing and tracing, and isolation strategies and social distancing, will continue to be needed."

The second study, conducted using Veterans Affairs electronic medical records from Feb 8 to Jul 22, showed that white patients made up 65% of the 254,595 patients tested for COVID-19, compared with black (26%) and Hispanic patients (9%). Of all patients tested, 73% were tested once, 16% were tested twice, 6% were tested three times, and 5% received at least four tests.

After including only one test per patient, testing rates were higher in black patients (6%) and Hispanic patients (5.3%) than in whites (3.9%). Rates of testing differed by age, sex, rural vs urban residence, region, and outbreak pattern.

Of the 16,317 patients who tested positive for the coronavirus, 44% were white, 40% were black, and 16% were Hispanic. Fully adjusted models showed that black and Hispanic patients, respectively, were 1.9 and 1.8 times more likely than whites to test positive. Hispanic patients were more likely than whites to test positive for COVID-19, regardless of region, date, and outbreak pattern.

Of the 8,625 patients who tested positive for COVID-19 by Jun 21, 457 white patients (49%), 392 black patients (42%), and 82 Hispanic patients (9%) died. However, after adjusting for age in black and Hispanic patients, 30-day death rates did not differ by race nor ethnicity. ...