I don't think so. Here's a study looking at Beijing that estimates about 15% of cases were transmitted presymptomatically: https://jech.bmj.com/content/75/1/84

I don't think so. Here's a study looking at Beijing that estimates about 15% of cases were transmitted presymptomatically: https://jech.bmj.com/content/75/1/84.full https://jech.bmj.com/content/75/1/84.full