1 Kaiser Permanente Vaccine Study Center, 1 Kaiser Plaza, Ordway Building, 16th Floor, Oakland, CA 94612, United States.
2 Kaiser Permanente Vaccine Study Center, 1 Kaiser Plaza, Ordway Building, 16th Floor, Oakland, CA 94612, United States. Electronic address: john.hansen@kp.org.
3 AstraZeneca, One MedImmune Way, Gaithersburg, MD 20878, United States.