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," Van Kerkhove said on Monday. "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."
However
A study in April found that viral shedding -- when people may be able to infect others -- could begin two to three days before symptoms appeared. In addition, the U.S. Centers for Disease Control and Prevention estimates in planning scenarios that 40% of coronavirus transmission is occurring before people feel sick.
"These patients weren't asymptomatic," Juthani said. Rather, they were "spreading disease before becoming symptomatic."
So maybe not good news. There's no way to tell if someone is getting sick in 3 days...
Overall, "these findings suggest that if we quarantine and contact trace symptomatic people, we can make a significant dent in the pandemic," Juthani said.
Making this distinction between asymptomatic and pre-symptomatic infections remains important -- but also between "paucisymptomatic infections," which refers to having atypical or very mild symptoms, Babak Javid, a principal investigator at Tsinghua University School of Medicine in Beijing and consultant in infectious disease at Cambridge University Hospitals, said in a written statement distributed by the U.K.-based Science Media Centre on Monday.
"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.
"Other data available, from studies in several continents confirming that presymptomatic transmission does occur, would suggest that being well does not necessarily mean one cannot transmit SARS-CoV-2," Javid said in part. "This has important implications for the track/trace/isolate measures being instituted in many countries."
- Infected and not getting any symptoms, chance you can / could have spread it is very rare.
- Infected and you are going to get atypical, mild symptoms or worse, you can spread the infection 3 days before symptoms show.
The good news is, that if you have tested positive but still don't have any symptoms after 2 weeks, you most likely will not have infected anyone else nor are contagious even though still testing positive.
There are outliers. The average incubation time is 5 days, 97.5% show symptoms within 11.5 days, longest recorded is 27 days.
https://www.sciencedaily.com/releases/2020/03/200317175438.htm
https://www.news-medical.net/news/20200224/Coronavirus-incubation-period-could-be-27-days-longer-than-previously-thought.aspx
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