- In a set of interim guidelines published on June 5, WHO estimated that 16 percent of people who contract SARS-CoV-2, the virus that causes COVID-19, never develop symptoms.
- In an asymptomatic infection, someone contracts the virus and never develops symptoms.
- In a pre-symptomatic infection, someone with the virus has not yet developed symptoms but eventually does so.
During a press briefing on Monday, an official from the World Health Organization (WHO) told reporters that asymptomatic transmission of SARS-CoV-2 appears to be “very rare.”
These comments were made by Maria Van Kerkhove, PhD, an epidemiologist who’s acting as the technical lead of WHO’s COVID-19 response. SARS-CoV-2 is the novel strain of coronavirus that causes COVID-19.
Van Kerkhove’s comments triggered swift pushback from public health experts who want people to know that if someone contracts SARS-CoV-2, they can pass it on to other people — even if they don’t have symptoms.
“The bottom line is that we don’t have a good handle on the extent of asymptomatic transmission that is truly present in the community. Until we do, such individuals should be considered infectious and must wear a face mask or facial covering,” Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York, New York, told Healthline.
“We need messaging from public health leaders that is coherent, unified, and without equivocation in order to maintain the public trust,” he added.
After Monday’s press briefing, Van Kerkhove later clarified that people can transmit SARS-CoV-2 even if they never develop symptoms of COVID-19.
“I did not say that asymptomatic cases cannot transmit; they can,” Van Kerkhove reportedly said during an interview with TIME. “The question is, do they? And if they do, how often is that happening?” she continued.
In a set of interim guidelines published on June 5, WHO estimated that 16 percent of peopleTrusted Source who contract SARS-CoV-2 never develop symptoms.
They based that estimate on the results of a preprint review of research, which has been posted online but not yet peer-reviewed.
The authors of that preprint review found that asymptomatic people can transmit the virus, but some research suggests they do so at lower rates than people with symptoms.