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, the study authors caution.
In considering the spread dynamics of the new coronavirus — or SARS-CoV-2 — researchers, and health authorities have been pondering the importance of “silent” transmission.
— John Pearce (@techpearce2) June 16, 2020
This concept says that people who may have contracted the virus but who do not experience any symptoms could unwittingly contribute to the spread by not realizing they are carriers.
Study conducted by Scripps Research
The study from the Scripps Research Translational Institute in La Jolla, CA, emphasizes just how many cases of SARS-CoV-2 infection are asymptomatic.
Its authors, behavioural scientist Daniel Oran and Dr. Eric Topol, Professor of Molecular Medicine at Scripps Research, warn that the high proportion of asymptomatic infections may contribute to the wide transmission of the virus.
Furthermore, they warn that even people who have not experienced any symptoms may still face long-term effects following exposure to the virus.
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.
Importance of rigorous testing
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 of US 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.
They also inferred that people who showed no COVID-19 symptoms were, nevertheless, liable to spread the virus over 14 days or more after infection. “The silent spread of the virus makes it all the more challenging to control,” notes Dr. Topol.
“Our review really highlights the importance of testing. It’s clear that with such a high asymptomatic rate, we need to cast a very wide net; otherwise, the virus will continue to evade us,” he adds.
Despite some confusing messages from WHO earlier this week, we know “asymptomatic transmission” does occur, although we are yet to pin down its exact role.
For instance, a recent review suggests as many as 40-45% of coronavirus infections are asymptomatic and they may transmit the virus to others for an extended period.
So, preventing asymptomatic transmission is another reason you may choose to wear a mask. That is, rather than wearing a mask to protect yourself, you could wear a mask to protect others.
Online Int’l News with additional input by GVS News Desk