| LurkerJ said: Coronavirus spread by asymptomatic people 'appears to be rare,' WHO official says "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 is very rare -- and much of that is not published in the literature," she said. "We are constantly looking at this data and we're trying to get more information from countries to truly answer this question. It still appears to be rare that an asymptomatic individual actually transmits onward." "When we actually go back and we say how many of them were truly asymptomatic, we find out that many have really mild disease," Van Kerkhove said. "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," she said. "Having said that, we do know that there can be people who are truly asymptomatic." "Detailed contact tracing from Taiwan as well as the first European transmission chain in Germany suggested that true asymptomatics rarely transmit. However, those (and many other) studies have found that paucisymptomatic transmission can occur, and in particular, in the German study, they found that transmission often appeared to occur before or on the day symptoms first appeared," Javid said in the statement. https://edition.cnn.com/2020/06/08/health/coronavirus-asymptomatic-spread-who-bn/index.html |
Lol they're backtracking already
https://www.ctvnews.ca/health/coronavirus/who-clarifies-comments-on-asymptomatic-spread-of-coronavirus-there-s-much-unknown-1.4976424
The organization held a live Q&A on its social media pages to address questions about comments made by a WHO official that suggested asymptomatic people only rarely spread COVID-19. The comments appeared to directly contradict guidance from public health organizations, including the U.S. Centers for Disease Control and Prevention, which have said about a third of coronavirus infections may be asymptomatic. The CDC also estimates that 40% of coronavirus transmission is occurring before people feel sick, meaning they are presymptomatic.
But it may boil down to how one defines "asymptomatic." 'THERE ARE SO MANY UNKNOWNS'
Maria Van Kerkhove, WHO's technical lead for coronavirus response and head of its emerging diseases and zoonoses unit, said during a media briefing in Geneva on Monday that "it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual."
But then on Tuesday, during the live Q&A, she clarified "this is a major unknown. 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, and to truly understand how many people don't have symptoms, we don't actually have that answered yet," Van Kerkhove said.
"We do know that some people who are asymptomatic, or some people who don't have symptoms, can transmit the virus on," she said. "So what we need to better understand is how many of the people in the population don't have symptoms and separately how many of those individuals go on to transmit to others."
Jumping the gun with a small subset of studies...
On Monday, Van Kerkhove had said that what appear to be asymptomatic cases of COVID-19 often turn out to be cases of mild disease.
"When we actually go back and we say how many of them were truly asymptomatic, we find out that many have really mild disease," Van Kerkhove said on Monday. "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. "Having said that, we do know that there can be people who are truly asymptomatic."
"What I was referring to yesterday in the press conference were very few studies -- some two or three studies that had been published that actually try to follow asymptomatic cases, so people who are infected, over time, and then look at all of their contacts and see how many additional people were infected," Van Kerkhove said. "And that's a very small subset of studies. So I was responding to a question at the press conference. I wasn't stating a policy of WHO or anything like that," she said. "Because this is a major unknown, because there are so many unknowns around this, some modeling groups have tried to estimate what is the proportion of asymptomatic people that may transmit."
Different findings in the UK
Liam Smeeth, professor of clinical epidemiology at the London School of Hygiene and Tropical Medicine, said that he was "quite surprised" by Van Kerkhove's original comments. "It goes against my impressions from the science so far that suggest asymptomatic (people who never get symptoms) and pre-symptomatic people are an important source of infection to others," Smeeth said In a written statement distributed by the U.K.-based Science Media Centre on Tuesday.
"There remains scientific uncertainty, but asymptomatic infection could be around 30% to 50% of cases," Smeeth said. "The best scientific studies to date suggest that up to half of cases became infected from asymptomatic or pre-symptomatic people."
