A Study on the Immune Response and Safety of the Shingles Vaccine and the Influenza Vaccine When Either is Given to Healthy Adults at the Same Time or Following a COVID-19 Booster Vaccine

Inclusion Criteria: * Participants who in the opinion of the investigator, can and who will comply with the requirements of the protocol (e.g., completion of the eDiaries, return for follow-up visits). * Written informed consent obtained from the participant prior to performance of any study-specific procedure. * Age at study entry: * For HZ/su and mRNA-1273 booster cohort: A male or female aged 50 years or older at the time of randomization. * For Flu D-QIV and mRNA-1273 booster cohort: A male or female aged 18 years or older at the time of enrollment. * Healthy participants or medically stable patients as established by medical history and clinical examination at screening. A stable medical condition is defined as disease not requiring significant change in therapy or hospitalization for worsening disease during the 3 months before enrolment. * Participants who have a documented previous mRNA-1273 primary vaccination series completed (i.e., both doses) at least 6 months prior to first vaccination. * Female participants of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as pre-menarche, current bilateral tubal ligation or occlusion, documented total hysterectomy, bilateral ovariectomy, or bilateral salpingectomy, or post-menopause. * Female participants of childbearing potential may be enrolled in the study, if the participant: * Has practiced effective contraception for 1 month prior to study intervention administratio…