It's going to be very difficult to assess in past clinical studies, because too many people did not have the information on what strain they were infected with. However, we do know, based on time periods, the likelihood of your being infected with one type of variant versus the other, so those assessments can be made. Yes, there are large cohort studies that could be used to assess that information, although they create a bit of an epidemiological study nightmare, but I think some things will work out in understanding that better.
One thing we do know is that omicron, for example, and delta were pretty distinct variants in terms of their population size and when they occurred, so that we have pretty understandable data, but those—