It's tricky: When you are testing an antiviral, you need subjects that have some symptoms but not ready to go to the hospital. You give the drug to half of them and give a placebo to the other half using a double blind process. Then you see what the outcome is. If the antiviral works, then most of the patients who received it never have to go to the hospital. But most patients with symptoms never have to go to the hospital anyway. So you might see something like 15% in a certain age group go with placebo, versus 5% go with the drug. That would be a huge result. It may be a little more subtle.
