A new study warns that around 40–45% of people who contract SARS-CoV-2 most likely remain symptom-free. Such cases may contribute to the “silent spread” of the virus. Moreover, even asymptomatic people may experience long-term respiratory issues.

Dr. Topol and Oran reviewed the data of SARS-CoV-2 studies that included clear information about testing methods for diagnosing infection with the virus.

They ended up assessing studies of 16 different cohorts, including groups of cruise ship passengers, prison inmates, and nursing home residents tested for COVID-19.

“What virtually all of them had in common was that a very large proportion of infected individuals had no symptoms,” notes Oran commenting on the findings.

“Among more than 3,000 prison inmates in four states who tested positive for the coronavirus, the figure was astronomical: 96% asymptomatic,” he emphasizes.

Looking at all the data together, the investigators estimated that around 40–45% of people contracting the new coronavirus are likely to be asymptomatic.

Looking at CT scan results for a cohort of 76 asymptomatic individuals who were present on the Diamond Princess cruise ship, they found that 54% of these individuals presented subclinical lung abnormalities.

“Our estimate of 40–45% asymptomatic means that if you’re unlucky enough to get infected, the probability is almost a flip of a coin on whether you’re going to have symptoms. So to protect others, we think that wearing a mask makes a lot of sense.”

Daniel Oran

Medical reference: MedicalNewsToday