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.

“It’s important data, that’s for sure,” said Benjamin Cowling, an epidemiologist at the University of Hong Kong who was not involved in the work. “And it does confirm what we’ve suspected for a long time — that asymptomatic cases can transmit infection.”…

“They don’t look any different from the symptomatic population” in terms of how much virus they carry, said Marta Gaglia, a virologist at Tufts University in Massachusetts who was not involved in the work. “There’s no actual reason to believe a priori that they would transmit any differently.”