Study design for participants receiving RZV. Stethoscopes represent clinician visits that occurred on the day of V1 (M1), the day of vaccine 2 (M3), 6 months after V1 (M5), and the most recent follow-up (M6). Syringes represent RZV administration with ≥8 weeks between V1 and vaccine 2. Notebooks represent symptom diary collection that occurred at clinician visits M1 and M3 and collected by study staff via telephone or e-mail. Drops represent blood samples that were collected 0 to 4 weeks prior to V1 (M0), >4 weeks after V1 (M2), >4 weeks after vaccine 2 (M4), and at 10 to 14 months after V1 (M6), if follow-up allowed.