World Health Organization retracts claim on asymptomatic spread of Covid-19

Thursday, 11 Jun, 2020

On top of that, Dr. Kerkhove said, "From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual".

"We have to take it a step at a time and say 'What do we know for sure and what is still conjecture?' and there's a heck of a lot that is still conjecture out there", Dr. Jameson said.

"Comprehensive studies on transmission from asymptomatic individuals are hard to conduct, but the available evidence from contact tracing reported by member states suggests that asymptomatically-infected individuals are much less likely to transmit the virus than those who develop symptoms", it said.

"The WHO created confusion yesterday when it reported that asymptomatic patients rarely spread the disease", an email from the Harvard Global Health Institute said Tuesday.

"I wasn't stating a policy of World Health Organization or anything like that", she continued.

During a discussion rebroadcast Tuesday on the WHO's Twitter account, Dr Van Kerkhove said she wanted to clarify a misunderstanding.

Prof Smeeth and other experts have said that understanding the risks of transmission among people with mild or no symptoms is crucial as governments begin to ease their lockdowns and gradually replace them with case tracking and isolation plans.

"We are constantly looking at this data and we're trying to get more information from countries that truly answer this question". Unfortunately, it is not very clear about how much transmission comes from people without symptoms, and the document acknowledges that there are only a few available studies on the matter.

Some scientists have expressed surprise at the WHO's statement.

At the live session, van Kerhove was questioned on the matter explained although some may not develop symptoms, they can still infect others.

"I used the phrase 'very rare, ' and I think that that's a misunderstanding to state that 'asymptomatic transmission globally is very rare, '" said Van Kerkhove.

What this means is that even if you feel fine, you could have the coronavirus and transmit it to others - not just because asymptomatic people may spread the disease, but because presymptomatic people certainly can. It should be noted that the CDC says that the infectiousness of asymptomatic people are relative to symptomatic people, and is estimated anywhere between 50% and 100%.

Dr Van Kerkhove cited "some estimates" that found between 6 and 40 per cent of the population of transmission may be due to asymptomatic transmission.

It was not the "intent of World Health Organization to say there is a new or different policy", said Mike Ryan, head of emergency programs for WHO.

"Whether they're fired up or not, that doesn't prevent them from getting the virus", said Bradley Pollock, chairman of the Department of Public Health Sciences at the University of California, Davis.

The underlying message seemed to be that while we've learned a lot about the virus since it first emerged late previous year, there are many unanswered questions.

How can I tell if someone is pre-symptomatic or asymptomatic?

. Infected people who will go on to experience symptoms can also sometimes transmit the virus before those symptoms manifest.