You had two questions. May I answer the first question?
In terms of changing course, that's with regard to the process. For example, again, you have to pay attention to the data and the information at the time. When information changes, you can't ignore it.
For example, we've recognized for years that Tamiflu is only effective as an antiviral if it's given within the first two days. Even then, it might only reduce the severity of illness for a day.