Spread of virus from people without symptoms is 'rare'

Wednesday, 10 Jun, 2020

Dr Van Kerkhove said that evidence showed that most people who were asymptomatic in fact had a very mild case of the coronavirus or were pre-symptomatic, that is, not yet displaying signs of the disease.

Some of the confusion lies in the distinction between the roles played by truly asymptomatic people and those who are merely pre-symptomatic - and later go on to become ill - in spreading the disease. She called the flap a "misunderstanding" and said she was trying to answer a reporter's question, not "stating a policy of World Health Organization or anything like that". They're following contacts. And they're not finding secondary transmission onward. "I was also referring to some data that isn't published", she said. We are constantly looking at this data and we're trying to get more information from countries to truly answer this question. "In addition to handing out face coverings and hand sanitizer at recent demonstrations, we are proud to now make available a pop-up site for anyone - with symptoms or not - and encourage those who have recently been in large groups to get tested and limit the further spread of COVID-19 in our community". Some studies, however, have estimated that people without symptoms (whether truly asymptomatic or presymptomatic) could be responsible for up to half of the spread, which is why the virus has been so hard to contain.

"T$3 o control the pandemic, it might not be enough for only persons with symptoms to limit their contact with others because persons without symptoms might transmit infection", the CDC said in its report at the time. Some modeling studies have assumed quite widespread asymptomatic transmission.

"They're not quote-unquote COVID symptoms - meaning they may not have developed fever yet, they may not have had a significant cough, or they may not have shortness of breath - but some may have mild disease", Van Kerkhove said.

The WHO previously based their guidelines on preliminary evidence from the earliest outbreaks, which indicated that the virus could spread from person-to-person contact, even if the carrier was asymptomatic. However, when they do, they appear to have higher viral loads on or just prior to the day of symptom onset, relative to later on in their infection.

But researchers from Harvard say the World Health Organization "created confusion" and that a multitude of evidence suggests those without symptoms can, and easily do, spread coronavirus. "And in that, I used the phrase 'very rare, ' and I think that that's misunderstanding to state that asymptomatic transmission globally is very rare".

Undertaking this response can "drastically reduce" the reach of the CCP (Chinese Communist Party) virus, Van Kerkhove said. In addition, some patients transmit the virus before developing symptoms.

Dr van Kerkhove stressed how important it was for countries to track symptomatic cases.

The Chinese city of Wuhan recently completed the testing of its entire population of 11 million in an effort to identify cases to avoid a resurgence of infections.

Ryan explained that just talking, exercising, breathing loudly and touching your mouth and then another surface are ways that asymptomatic people can spread the coronavirus.