Problem: What does the data tell you about the frequency and severity of AEs? How does the AE profile change after dose 1 vs. dose 2? Why do you think the AE profile changes from dose to dose? What do you think might be some of the complicating factors (confounding factors) when trying to assess AE safety vs. efficacy (benefit: risk) that is unique for vaccines vs. other drugs/biologics/medical devices (hint: vaccines are trying to elicit an immune response whereas most other therapies are trying to REDUCE immune response)?