The purpose of this study is to explore the physiological and behavioral impact of the immune response to vaccines after receipt of investigational or approved messenger ribonucleic acid (mRNA) vaccines using wearable medical sensors, with the potential of establishing a digital biomarker of vaccine response due to stimulation of the immune system.

Participants will be provided wearable medical sensor equipment and instructions at the start of the study. Participants will have access to device support throughout the study period. The wireless medical devices will be applied prior to vaccination in the concurrent Moderna-sponsored vaccine trial in order to establish an initial baseline of participants' daily physiological patterns.

Inclusion Criteria:

• Enrolled in a concurrent Moderna-sponsored vaccine clinical trial.
• Investigator assessment that participant understands and is willing and physically able to comply with wearing the sensors and follow-up as outlined in the study protocol, including all procedures.
• Participant has provided written informed consent for participation in this study, including all evaluations and procedures as specified in the study protocol.

Exclusion Criteria:

• History of hypersensitivity or allergic reaction to medical adhesive or other history of skin irritation, that, in the opinion of the investigator, contraindicates their use of a wearable medical device.
• Broken skin at the site of wearable location
• Implanted, permanent pacemaker

Participants enrolled in the multi-center, concurrent Moderna-sponsored vaccine trial will be provided the opportunity to enroll in this study. Participants will be screened for eligibility based on their concurrent enrollment in the vaccine trial.