The spread of Covid-19 by someone who is not showing symptoms appears to be rare, Maria Van Kerkhove, the World Health Organization’s technical lead for coronavirus response and head of the emerging diseases and zoonoses unit, said during a media briefing in Geneva on Monday.
“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,” Dr Maria Van Kerkhove said, adding that more research and data are needed to ‘truly answer’ the question of whether the coronavirus can spread widely through asymptomatic carriers.
Van Kerkhove said WHO is now relying on data obtained through contact tracing even as she urged governments to focus on detecting and isolating infected people with symptoms, as well as tracking anyone who might have come into contact with them.
“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,’ she added.
Van Kerkhove went on to describe how the novel coronavirus, a respiratory pathogen, spreads through droplets, which can be released when someone coughs or sneezes.
“It passes from an individual through infectious droplets. If we actually followed all of the symptomatic cases, isolated those cases, followed the contacts and quarantined those cases, we would drastically reduce — I would love to be able to give a proportion of how much transmission we would actually stop — but it would be a drastic reduction in transmission,” she said.
Van Kerkhove also said that what appear to be asymptomatic cases of Covid-19 often turn out to be cases of mild disease.