You’ve spent the last few months worried about catching coronavirus from elevator buttons and cereal boxes, and rightly so: It’s best to be very careful when it comes to containing the spread. But a new study shows there’s a very good chance that you’ll catch COVID-19 from another source: someone else who never knew they were even infected.
A Stealth Mode of Infecting
Researchers at the Scripps Research Translational Institute studied data sets from 16 different groups of COVID-19 patients, including people in Iceland and Italy; from homeless shelters in New York and Los Angeles; and those on the Diamond Princess cruise ship. Their conclusion: at minimum, 30%, and more likely 40% to 45%, of people who were asymptomatic transferred the virus to others.
“The likelihood that approximately 40% to 45% of those infected with SARS-CoV-2 will remain asymptomatic suggests that the virus might have greater potential than previously estimated to spread silently and deeply through human populations,” said the study, published in the Annals of Internal Medicine.
“The range we found is extraordinarily high,” says Dr. Eric Topol, director and founder of the Institute and one of the authors of the paper, to Time Magazine. “That means the range of what can happen with SARS-CoV-2 is from no symptoms to [death]. That’s not at all similar to any virus or pathogen we’ve experienced that has killing potential in the past. What we have here is an extraordinary spectrum, including this quiet, stealth mode of infecting somebody.”
Causes Abnormalities in the Lungs
“People who are getting infection without symptoms are actually doing a lot of damage to their bodies and they don’t know it,” said Topol to Time. (Other studies have found something similar.)
Take the cruise ship for example. “The finding that 54% of the 76 asymptomatic persons on the Diamond Princess who were examined by computed tomography appeared to have significant subclinical abnormalities in their lungs is disturbing,” said the study. “Further research will be required to confirm this potentially important finding, taking into account possible confounding factors, including the age of passengers aboard the Diamond Princess. If confirmed, this finding suggests that the absence of symptoms might not necessarily mean the absence of harm.“
What Can You Do About It?
Topol tells Time this is why wearing a mask is so essential and “basically the reason why we have to all wear masks—because nobody knows who is an asymptomatic carrier. The person doesn’t know it and the person’s contacts don’t know it. That has enormous implications and it’s an area we need to study more, on how to test people without symptoms on a very large scale to understand these people better and follow them to determine precisely their ability to transmit [the virus].”
As for yourself: To get through this pandemic at your healthiest, don’t miss these Things You Should Never Do During the Coronavirus Pandemic.