Patients With No Symptoms Caused 44 Percent Of Coronavirus Cases: Study

Nearly half of coronavirus cases were transmitted by patients who initially showed no symptoms, according to a new study.

Researchers said COVID-19 patients admitted to China’s Guangzhou Eighth People’s Hospital were likely contagious for days before the onset of symptoms, according to a report published Wednesday in Nature.

The study collected throat swabs for 32 days after symptoms began for 94 patients admitted from Jan. 21 through Feb. 14.

“We observed the highest viral load in throat swabs at the time of symptom onset, and inferred that infectiousness peaked on or before symptom onset,” researchers wrote.

Referencing other studies on the spread of the virus, researchers said it’s likely that the patients were contagious for two to three days before their symptoms began, according to the report.

“This indicates that a significant portion of transmission may have occurred before infected persons have developed symptoms,” researchers wrote.

Through using modeling systems, the researchers estimated that 44% of cases were transmitted during the presymptomatic stage.

“With a substantial proportion of presymptomatic transmission, measures such as enhanced personal hygiene and social distancing for all would likely be the key instruments for community disease control,” the authors concluded.

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