[Dr. Franklin]

So what I get from the graph is that taking the clot shot is one big FU, since that repeats eight times on the X axis.

[MtnClimber]

The graph shows data for four antibodies G1-G4. It shows measurements for two shots 2nd and 3rd as well as two intervals from the shots: a measurement close to the shot (post) and another measurement delayed more from the shot, the Follow-Up (FU) measurement that has time for more antibody response.

You are right that choosing to get the jabs may be a FU.