It would be a big deal if true: An official with the World Health Organization suggested Monday that so-called silent spreaders aren't as common as thought when it comes to COVID-19. "From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual," said Dr. Maria Van Kerkhove, per CNBC. "They’re not finding secondary transmission onward. It's very rare." Those comments immediately prompted a reaction from other health experts that amounted to, "wait, what?" And on Tuesday, Kerkhove herself sought to clarify, saying much more research is needed on this "complex question." She called the flap a "misunderstanding" and said she was trying to answer a reporter's question, not "stating a policy of WHO or anything like that."
Her comments Monday were based on a handful of small studies out of nations conducting contact tracing in asymptomatic cases, and the BBC notes Kerkhove said those studies don't always handle three different categories of patients in the same way: the truly asymptomatic (those with no symptoms); the pre-symptomatic (those who have no symptoms when they test positive but soon develop them); and those who have very mild symptoms. Another factor: Contact tracing might not be accurate enough to draw conclusions. The issue is of huge importance because social distancing measures are in part driven by the fear that asymptomatic people (as much as 16% of the population, per studies) can spread the disease to scores of others without realizing it, reports the Washington Post. Its story rounds up initial reaction and provides context to Kerkhove's original comments. For now, the gist seems to be "stay tuned." (Read more coronavirus stories.)