COVID-19Phase 4SHIELDNCT06633835
Impact of Reactogenicity of the 2024-2025 COVID-19 Vaccines on Health Care Workers and First Responders in the United States
A Phase 4 study testing protein subunit: Novavax COVID-19 vaccine and Pfizer mRNA COVID-19 vaccine in people with COVID-19 and Vaccine-Preventable Diseases, run by Novavax at 1 site in United States.
Trial summary
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 Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- COVID-19, Vaccine-Preventable Diseases, SARS CoV 2 Infection
- What is being tested?
- protein subunit: Novavax COVID-19 vaccine and Pfizer mRNA COVID-19 vaccine
- Type of treatment
- Vaccines
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 660 participants
- Where
- 1 siteUnited States
- Study dates
- 19 Sep 2024to 30 Jun 2025
- Phase
- Phase 4
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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)
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Utah School of Medicine
Salt Lake City, Utah, 84108
About this study
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
Read the detailed description
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.
- Conditions
- COVID-19, Vaccine-Preventable Diseases, SARS CoV 2 Infection
- Being tested
- protein subunit: Novavax COVID-19 vaccine, Pfizer mRNA COVID-19 vaccine
- Keywords
- COVID-19
- Medical subject headings
- COVID-19, Vaccine-Preventable Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
protein subunit: Novavax COVID-19 vaccineBiological
Also called 2024-25 COVID-19 vaccination
Participants will receive a single dose (0.5 ml) of study vaccine Novavax COVID-19 vaccine, 2024-2025 formula (JN.1 containing) in the deltoid muscle of the arm.
Pfizer mRNA COVID-19 vaccineBiological
Also called 2024-2025 formula
Participants will receive a single dose (0.3 ml) of study vaccine Pfizer mRNA COVID-19 vaccine, 2024-2025 formula (KP.2 containing) in the deltoid muscle of the arm.
| Study group | Role | What they receive |
|---|---|---|
| 2024-25 updated Novavax COVID-19 | Active comparator | Participants will receive a single dose (0.5 ml) of study vaccine Novavax COVID-19 vaccine, 2024-2025 formula (JN.1 containing) in the deltoid muscle of the arm. Receives: Biological: protein subunit: Novavax COVID-19 vaccine |
| Pfizer mRNA COVID-19 | Active comparator | Participants will receive a single dose (0.3 ml) of study vaccine Pfizer mRNA COVID-19 vaccine, 2024-2025 formula (KP.2 containing) in the deltoid muscle of the arm. Receives: Biological: Pfizer mRNA COVID-19 vaccine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of participants with solicited systemic reactogenicity symptoms.
Percentage of participants that experienced any solicited systemic reactogenicity symptoms after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during the first two days post vaccination.
Measured: Day 0 to Day 2
Secondary outcomes (5)
Percentage of participants with solicited local reactogenicity symptoms.
To determine the difference in the percentage of participants that experienced any solicited local reactogenicity symptoms after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during first two days post vaccination.
Measured: Day 0 to Day 2
Number of Participants with solicited systemic reactogenicity symptoms
Number of Participants with solicited systemic reactogenicity symptoms experienced by participants after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during the first two days post vaccination.
Measured: Day 0 to Day 2
Percentage of participants that experienced multiple solicited systemic reactogenicity symptoms.
Percentage of participants that experienced multiple solicited systemic reactogenicity symptoms after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during the first two days post vaccination.
Measured: Day 0 to Day 2
Percentage of participants who experienced any local and systemic solicited reactogenicity symptoms.
Percentage of participants who experienced any Local and systemic solicited reactogenicity symptoms that were reported as severity of 2 or higher after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during the first two days post vaccination.
Measured: Day 0 to Day 2
Number of Participants Reporting Perceived Impact on Daily Activities (Work, Social, and Family Life)
Number of participants experiencing any perceived impact on their work, social life, and family/home responsibilities within the first 2 days post-vaccination, comparing responses between Novavax and Pfizer-BioNTech mRNA vaccine recipients."
Measured: Day 0 to Day 2
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Oct 2024
- Study start19 Sep 2024
- Primary completion30 Dec 2024
- Study completion30 Jun 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for COVID-19Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Model description
- 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.
- Masking
- None (open label)
- Enrolment
- 660 participants (actual)
Sponsor and investigators
- Lead sponsor
- Novavax
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- University of Utah
- Responsible party
- Sponsor
- Investigators
- Sarang K Yoon, MOH, Principal investigator, University of Utah
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06633835
- Sponsor's protocol ID
- 2019nCoV-415
- Acronym
- SHIELD
- Status last verified
- May 2026
- First submitted
- 4 Oct 2024
- Last updated
- 2 Jun 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 2 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Reactogenicity of the 2024-2025 COVID-19 Vaccines on Health Care Workers and First Responders in the United States
- ClinicalTrials.gov ID
- NCT06633835
- Acronym / sponsor ID
- SHIELD / 2019nCoV-415
- Conditions
- COVID-19, Vaccine-Preventable Diseases, SARS CoV 2 Infection
- Keywords
- COVID-19
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 660 participants (actual)
- Lead sponsor
- NovavaxIndustry (pharma, biotech, devices)
- Collaborators
- University of Utah
- Study start
- 19 Sep 2024 (actual)
- Primary completion
- 30 Dec 2024 (actual)
- Study completion
- 30 Jun 2025 (actual)
- First posted
- 9 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Detailed description
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| 2024-25 updated Novavax COVID-19 | Active comparator | Biological: protein subunit: Novavax COVID-19 vaccineParticipants will receive a single dose (0.5 ml) of study vaccine Novavax COVID-19 vaccine, 2024-2025 formula (JN.1 containing) in the deltoid muscle of the arm. |
| Pfizer mRNA COVID-19 | Active comparator | Biological: Pfizer mRNA COVID-19 vaccineParticipants will receive a single dose (0.3 ml) of study vaccine Pfizer mRNA COVID-19 vaccine, 2024-2025 formula (KP.2 containing) in the deltoid muscle of the arm. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (4 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| protein subunit: Novavax COVID-19 vaccineAlso: 2024-25 COVID-19 vaccinationParticipants will receive a single dose (0.5 ml) of study vaccine Novavax COVID-19 vaccine, 2024-2025 formula (JN.1 containing) in the deltoid muscle of the arm. | Biological | 2024-25 updated Novavax COVID-19 |
| Pfizer mRNA COVID-19 vaccineAlso: 2024-2025 formulaParticipants will receive a single dose (0.3 ml) of study vaccine Pfizer mRNA COVID-19 vaccine, 2024-2025 formula (KP.2 containing) in the deltoid muscle of the arm. | Biological | Pfizer mRNA COVID-19 |
Primary outcome
Percentage of participants with solicited systemic reactogenicity symptoms.
Time frame: Day 0 to Day 2
Percentage of participants that experienced any solicited systemic reactogenicity symptoms after receiving a single dose of 2024-25 Novavax COVID-19 vaccine or 2024-25 Pfizer-BioNTech mRNA COVID-19 vaccine during the first two days post vaccination.
5 secondary outcomes
Percentage of participants with solicited local reactogenicity symptoms.
Time frame: Day 0 to Day 2
Number of Participants with solicited systemic reactogenicity symptoms
Time frame: Day 0 to Day 2
Percentage of participants that experienced multiple solicited systemic reactogenicity symptoms.
Time frame: Day 0 to Day 2
Percentage of participants who experienced any local and systemic solicited reactogenicity symptoms.
Time frame: Day 0 to Day 2
Number of Participants Reporting Perceived Impact on Daily Activities (Work, Social, and Family Life)
Time frame: Day 0 to Day 2
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Jun 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sarang K Yoon, MOH principal investigator
University of Utah
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing protein subunit: Novavax COVID-19 vaccine and Pfizer mRNA COVID-19 vaccine in people with COVID-19 and Vaccine-Preventable Diseases, run by Novavax at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 2 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of participants with solicited systemic reactogenicity symptoms. (time frame: Day 0 to Day 2). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Jun 2026.