COVID-19: Hydroxychloroquine & Hypoxic Pneumonia / Timing of Viral Shedding & Transmission / Coinfection with Other Respiratory Pathogens

By Amy Orciari Herman

Edited by Susan Sadoughi, MD, and Richard Saitz, MD, MPH, FACP, DFASAM

Take a look at some of the latest research on novel coronavirus disease (COVID-19):

Hydroxychloroquine & hypoxic pneumonia: Researchers in France examined the medical records of 84 patients with COVID-19 requiring oxygen who received hydroxychloroquine (600 mg daily) and 97 similar patients who did not get the drug. The primary outcome — transfer to the ICU or death from any cause within 7 days — did not differ significantly between the groups (in a weighted analysis, roughly 21%-22% of patients). The researchers say the findings "do not support the use of [hydroxychloroquine] in patients hospitalised for a documented SARS-CoV-2 pneumonia." The study appears on the preprint server medRxiv.

Timing of viral shedding & transmissibility: Reporting in Nature Medicine, researchers in China examined viral load data on some 90 COVID-19 patients, as well data on the timing of transmission among nearly 80 transmission pairs (that is, one person likely infected the other). Combining these data — and assuming an incubation period of 5.2 days — the researchers conclude that infectiousness began 2.3 days before symptom onset and peaked 0.7 days before symptoms began. They also estimate that presymptomatic transmission accounted for 44% of secondary cases among the transmission pairs.

Coinfection with other respiratory pathogens: In a sample of 1200 patients with respiratory symptoms in California, 21% of nasopharyngeal swab specimens that tested positive for SARS-CoV-2 also tested positive for other respiratory pathogens, like rhinovirus/enterovirus and respiratory syncytial virus. Additionally, of those that tested positive for non-SARS-CoV-2 pathogens, 8% also tested positive for SARS-CoV-2. Writing in JAMA, the researchers conclude, "The presence of a non–SARS-CoV-2 pathogen may not provide reassurance that a patient does not also have SARS-CoV-2."

Decontaminating N95 masks: A study on decontamination strategies for disposable N95 masks, reported on the preprint server medRxiv, found that 70% ethanol and ultraviolet light each significantly degraded mask integrity. For ethanol in particular, further degradation was noted 30 minutes after decontamination. Vaporized hydrogen peroxide, meanwhile, did not significantly change mask integrity after two treatments. In addition, the investigators applied virus to the masks, and virus was still detected after decontamination with vaporized hydrogen peroxide and ultraviolet light — but not after decontamination with ethanol.

Predicting the pandemic's course: The authors of an opinion piece in the Annals of Internal Medicine urge caution in using the Institute for Health Metrics and Evaluation's model for predicting the trajectory of the COVID-19 pandemic. They point out potential flaws with the model, including use of unreliable mortality data. They write, "For hospital demand projections, patient-level clinical outcome data will enable more accurate conclusions than poorly reported worldwide aggregate mortality data."