Researchers in South Korea found that roughly 30 percent of those infected never develop symptoms yet probably spread the virus.
Of all the coronavirus’s qualities, perhaps the most surprising has been that seemingly healthy people can spread it to others. This trait has made the virus difficult to contain, and continues to challenge efforts to identify and isolate infected people.
Most of the evidence for asymptomatic spread has been based on observation (a person without symptoms nevertheless sickened others) or elimination (people became ill but could not be connected to anyone with symptoms).
A new study in South Korea, published Thursday in JAMA Internal Medicine, offers more definitive proof that people without symptoms carry just as much virus in their nose, throat and lungs as those with symptoms, and for almost as long. Continue reading.