Do you have a study with hard data on the number of people infected by asymptomatic carriers?
All I’ve seen in the studies I’ve read so far are models, inferences, and estimates, with ridiculously high error bars, but no hard data.
No, and I don’t know how you would possibly conduct such a study to get hard data. They are asymptomatic after all.
You can go back and look at the German study on the initial spreader in Germany and the amount of time she was asymptomatic and the number of people who she infected.
Unless you believe that there are a lot of people going out into public with symptoms, then you kind of have to assume that most people get it from asymptomatic people.
I thought about nursing homes in response to your question. But even considering they send a symptomatic person back into the nursing home. Unless you assume that person wasn’t sufficiently isolated, then medical workers are getting it from the symptomatic person and transmitting it to the other patients while the medical worker is still asymptomatic.
Same thing in hospitals. Yes there were a couple of early cases where doctors worked for days while experiencing symptoms, but that’s the exception. Most get it and spread it while asymptomatic.
Hospitals in Boston requred all workers and patients to wear masks and saw a greater than 50% drop in new cases a day.