COVID-19 Scan for Aug 27, 2020

Hydroxychloroquine, azithromycin for COVID
COVID-19 antibody test performance

Review of COVID studies links increased death to hydroxychloroquine plus azithromycin

A systematic review and meta-analysis of studies involving COVID-19 patients treated with hydroxychloroquine found that the antimalaria drug alone was not associated with reduced mortality in hospitalized patients, but when combined with the antibiotic azithromycin it was linked with significantly increased mortality, European researchers reported yesterday in Clinical Microbiology and Infection.

The researchers looked at 29 studies published up until Jul 25, including 3 randomized controlled trials (RCTs) and 1 non-randomized trial. After excluding 11 studies with critical risk of bias, the meta-analysis included 11,932 patients treated with hydroxychloroquine, 8,081 treated with hydroxychloroquine and azithromycin, and 12,930 who received neither drug. The investigators compared mortality between patients treated with hydroxychloroquine and those treated with the standard of care, as well as death rates with hydroxychloroquine plus azithromycin.

The results of the meta-analysis showed that the relative risk (RR) of death for patients treated with hydroxychloroquine was 17% lower than for patients treated with standard of care (pooled RR, 0.83; 95% confidence interval, 0.65 to 1.06) for all studies and 9% higher for the RCTs (pooled RR, 1.09; 95% CI, 0.97 to 1.24). Neither of those results was considered statistically significant.

Treatment with hydroxychloroquine and azithromycin, however, was associated with a 27% increase in mortality compared with standard of care (pooled RR, 1.27; 95% CI, 1.04 to 1.54).

The authors of the study say the results confirm preliminary findings of several observational trials that showed the combination of hydroxychloroquine and azithromycin might increase the risk of life-threatening cardiovascular events.

"In conclusion, the meta-analysis clearly shows that hydroxychloroquine alone is not effective for the treatment of COVID-19 patients and that the combination of hydroxychloroquine and azithromycin increases the risk of mortality," they wrote.
Aug 26 Clin Microbiol Infect study


Comparison of COVID-19 antibody tests reveals wide range of performance

An evaluation of assays to detect antibodies against SARS-CoV-2, the virus that causes COVID-19, has found a wide range of performance, underscoring the need for rigorous test validation with standardized sample sets.

The study, published today in Nature Biotechnology, involved a comparison of 10 point-of-care lateral flow assays (LFAs) and two lab-based enzyme-linked immunosorbent assays (ELISAs) in 5-day intervals from symptom onset. Specificity was determined using blood samples donated before the pandemic.

Researchers studied 128 serum or plasma specimens from 79 patients who tested positive for COVID-19 at San Francisco hospitals. The percentage of specimens testing positive rose over time, peaking at 16 to 20 days and at more than 20 days. Four tests (Bioperfectus, Premier, Wondfo, and an in-house ELISA) had a positivity rate higher than 80% and specificity higher than 95%.

All assays' ability to detect immunoglobulin G was more consistent than that for immunoglobulin M, which affected overall test specificity (range, 84.3% to 100.0%). One LFA generated false-positive results in 30 samples.

The authors said that widely available, reliable antibody assays would produce more accurate estimates of COVID-19 prevalence and incidence. On Feb 4, the Department of Health and Human Services issued an emergency use authorization (EUA) for polymerase chain reaction and immunoassay diagnostic tests without formal Food and Drug Administration (FDA) approval. As a result, dozens of companies began selling lab-based and point-of-care tests without the backing of rigorous performance data.

The researchers called for validation using standard sample sets with known positive results from patients with different signs and symptoms at different time points, pre-pandemic blood samples, and control samples from people with other viral or inflammatory diseases.

"Coordinated efforts to ensure widespread availability of validated sample sets would facilitate data-driven decisions on the use of serology," they wrote. "The updated guidance released by the FDA in early May 2020 and the initiative recently launched by the FDA and the US National Cancer Institute/National Institutes of Health to systematize data generation for EUAs are substantive steps toward this goal."
Aug 27 Nat Biotechnol study

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