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WHO clarifies comments about asymptomatic coronavirus spread; experts weigh in

What experts are saying about reports of no asymptomatic spread

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In this Wednesday, Jan. 29, 2020 file photo, Maria van Kerkhove, head of the Outbreak Investigation Task Force for the World Health Organization speaks during a news conference regarding the COVID-19 coronavirus, at the European headquarters of the United Nations in Geneva, Switzerland.

In this Wednesday, Jan. 29, 2020 file photo, Maria van Kerkhove, head of the Outbreak Investigation Task Force for the World Health Organization speaks during a news conference regarding the COVID-19 coronavirus, at the European headquarters of the United Nations in Geneva, Switzerland.

AP

A report from CNBC about asymptomatic patients and the coronavirus went viral on Monday. But experts aren’t so sure about the conclusions.

What the report said:

  • According toCNBC, the World Health Organization said asymptomatic spread of the novel coronavirus is “very rare.”
  • Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonosis unit, said at a news briefing: “From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual. It’s very rare.”
  • “We have a number of reports from countries who are doing very detailed contact tracing. They’re following asymptomatic cases. They’re following contacts. And they’re not finding secondary transmission onward. It’s very rare.”
  • Van Kerkhove said more research and data are needed before making the firm stance that asymptomatic patients can’t spread the virus, per CNBC.
  • Van Kerkhove said Tuesday: “The majority of transmission that we know about is that people who have symptoms transmit the virus to other people through infectious droplets. But there are a subset of people who don’t develop symptoms. To truly understand how many people don’t have symptoms, we don’t actually have that answer yet.” 

Experts don’t exactly agree

  • The WHO said preliminary evidence from the outbreak suggested the virus could spread from people who don’t have symptoms.
  • Experts said the new report needs to be approached with caution. In fact, Dr. Mike Ryan, executive director of the WHO’s emergencies program, said asymptomatic spread occurs, per CNBC: “There is much to be answered on this. There is much that is unknown. It’s clear that both symptomatic and asymptomatic individuals are part of the transmission cycle. The question is what is the relative contribution of each group to overall number of cases.”
  • Ashish Jha, incoming dean at the Brown School of Public Health, said he wasn’t sure whether the World Health Organization is referring to asymptomatic (those who have it but never get symptoms) cases or presymptomatic cases (those who have the virus but haven’t started showing symptoms).

Peter Hotez, an infectious disease expert at Baylor University, said he wondered if the Centers for Disease Control and Prevention will agree with the WHO’s findings: “If this turns out to be true it would be a game-changer, but I think it would be really important for us to know whether CDC concurs?”