> Research early in the pandemic suggested that the rate of asymptomatic infections could be as high as 81%. But a meta-analysis published last month, which included 13 studies involving 21,708 people, calculated the rate of asymptomatic presentation to be 17%. The analysis defined asymptomatic people as those who showed none of the key COVID-19 symptoms during the entire follow-up period, and the authors included only studies that followed participants for at least seven days.
There are many more I've read where the authors have tried to quantify asymptomatic spread and been found wanting (studies on children are particularly enlightening). I wouldn't be surprised if the final figure ends up being very close to, if not, zero, though we're still in the clutches of the initial panic so I suspect those findings to take time due more to social resistance than the frictions involved in actual science.
[1] https://www.nature.com/articles/d41586-020-03141-3?error=coo...