To assess the impact of reactogenicity among health care workers and first responders receiving an updated 2024-25 Novavax COVID-19 vaccine as compared with those receiving an updated 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine

This is a prospective interventional study of health care workers (HCW) and first responders (FR) receiving an updated 2024-25 COVID-19 vaccination at the University of Utah (UT). Participants can choose which COVID-19 vaccine type they would like to receive from the study team. For this study, health care workers and first responders are defined as anyone having direct face-to-face contact, defined as being within 3 feet, or about an arm's length, with patients as part of their full-time or part-time (greater than or equal to 20 hours per week) job responsibilities.

Approximately 660 health care workers and first responders from Salt Lake City, Utah and surrounding areas will be enrolled into the study. This study will only enroll participants who intend to get an updated 2024-25 COVID-19 vaccine during Fall/Winter 2024-25 SARS-CoV-2 virus circulation. Eligible participants will choose their desired vaccine type (protein subunit: Novavax, or mRNA: Pfizer). Study vaccinators will then administer the chosen vaccine. Following vaccination, study participants will receive a post vaccination questionnaire 48-hours after vaccine administration. Self-reported information on systemic and local reactogenicity symptoms, socio-demographics, occupational history, medical history, COVID-19 and flu vaccine history, and impact on daily activities and work will be collected through the post vaccination questionnaire.

Inclusion Criteria:

• Adults aged 18 years and older who have received at least one COVID-19 vaccination in the past 4 years
• Health care workers or first responders who have direct face-to-face contact, defined as being within 3 feet, or about an arm's length, with patients as part of their full-time or part-time (greater than or equal to 20 hours per week) job responsibilities
• Intends to receive a dose of the updated 2024-25 COVID-19 vaccine
• Able to understand and provide informed consent
• Comfortable reading and responding to text messages and emails sent in English or having an interpreter assist them
• Able and willing to comply with all study requirements
• Access to a smartphone, tablet, or computer to complete the consent, screener and study questionnaires

Exclusion Criteria:

• Ongoing participation in other vaccine or investigational product trials within 90 days of study enrollment
• History of self-reported severe allergic reaction to prior COVID-19 vaccine
• Receipt of COVID-19 vaccine within 60 days of enrollment
• Plans to receive additional vaccines within 7 days after the vaccination visit for study enrollment. (Co-administered vaccinations at time or day of COVID-19 vaccination are permissible)

Active comparator