Yellow Fever Vaccination ReactionPhase 4NCT05374317

Study of the Safety and Immunogenicity of Reduced Doses of the US Yellow Fever Vaccine

A Phase 4 study testing Yellow Fever Vaccine in people with Yellow Fever Vaccination Reaction, run by US Army Medical Research Institute of Infectious Diseases at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Who is it for?: Ages 18 to 50 yearsHealthy volunteers can take part
Conditions the study is for: Yellow Fever Vaccination Reaction
What is being tested?: Yellow Fever Vaccine
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 88 participants
Where: 1 siteUnited States
Study dates: 7 Jun 2021to 2 Nov 2022
Phase: Phase 4
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 to 50 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

Males and Females 18 to 50 years of age.
In good health, as determined by pertinent medical history, physical examination, vital signs, and clinical safety laboratory evaluations.
Female of child bearing potential: Has a negative pregnancy test and is willing to use a reliable form of contraception for the duration of the study after vaccination.
Negative human immunodeficiency virus (HIV) antibody screen, seronegative for hepatitis B surface antigen (HBsAg) and hepatitis C antibody (following HIV and hepatitis testing, subjects will be provided with counseling and referral for health care if any test is positive).
Ability to comprehend and a willingness to sign an informed consent, which includes the Health Insurance Portability and Accountability Act (HIPAA) Authorization, and a separate consent form for HIV testing.
Be willing to comply with all follow-up visits, testing, adverse event (AE) reporting, and completion of diary card.

Who cannot join

Receipt of any other investigational vaccine or investigational drug within 28 days prior to or after vaccination with YF-VAX® vaccine.
Have had any known flavivirus disease or receipt of any flavivirus vaccine, licensed or investigational at any time; in addition to any yellow fever vaccine, these include; Japanese Encephalitis (JE), St. Louis Encephalitis, Tick Borne Encephalitis (TBE), West Nile, Dengue, Zika virus
Anticipates receipt of any other vaccine within 28 days of YF-VAX®. Influenza vaccination will be permitted but not within 14 days of YF-VAX®.
Acute or chronic medical conditions, or medications that, in the Principal Investigator's (PI) opinion, would impair the subject's ability to respond to vaccination.
Hypersensitivity to any vaccine, eggs or egg products, or allergy to any component of the YF-VAX® (sorbitol, gelatin) or latex.
Corticosteroids ≥20 mg/day of prednisone for ≥ 2 weeks suppresses the immune system. Low-dose corticosteroid topical products and nasal sprays used sporadically (i.e. prn--according to circumstances) are permissible.

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History of immunosuppression, by any cause--primary or acquired immunodeficiencies, transplantation, malignant neoplasm, lymphoma, leukemia, thymoma, myasthenia gravis, radiation, immunosuppressive drugs, including antimetabolites, tumor necrosis factor (TNF)-alpha inhibitors (etanercept), interleukin-1 (IL-1) blocking agents and other monoclonal antibodies targeting immune cells (e.g., rituximab, alemtuzumab, etc), etc.
Receipt of or anticipates receipt of/or donation of blood or blood products for 2 months after receipt of YF-VAX®. (Note: Blood banks require a minimum 2 week interval between the receipt of this FDA licensed vaccine and blood donations; however because of the blood collections in this study, an interval of 2 months is requested).
Female: Pregnant (or planning to become pregnant) or breastfeeding for the duration of the study after receipt of YF-VAX®.
Clinically significant abnormal laboratory tests (generally 2 times the upper limit of normal or as determined by the PI).

Trial locations and contacts

1 site in 1 country.

United States1 site

United States Army Medical Research Institute of Infectious Diseases
Frederick, Maryland, 21702

Other trials in United States

About this study

Official title: An Exploratory, Pilot Study of the Safety and Immunogenicity of Reduced Doses of the US Yellow Fever Vaccine

This is an open-label, randomized, exploratory study to evaluate the human immune response to reduced subcutaneous (SQ) dosing of Yellow Fever vaccine compared to the standard FDA approved subcutaneous vaccination dose. The current dose of the US FDA licensed Yellow Fever vaccine is approximately 55,000 plaque-forming unit(s) (PFU) in 0.5 mL administered SQ. Using the licensed dosage as standard, investigators are evaluating reduced doses of 1/5th (0.10 mL) and 1/10th (0.05 mL) standard Yellow Fever vaccine (YF-VAX).

Read the detailed description

Up to 150 individuals will be screened in order to randomize 90 eligible individuals to one of three groups: Group 1- YF-VAX® standard dose 0.5 mL SQ = 30 subjects; Group 2-0.10 mL (1/5th) SQ = 30 subjects; Group 3-0.05 mL (1/10th) SQ = 30 subjects.

Conditions: Yellow Fever Vaccination Reaction
Being tested: Yellow Fever Vaccine

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Yellow Fever VaccineBiological
Also called YF-VAX
Administered subcutaneously once.

Study groups in NCT05374317
Study group	Role	What they receive
Standard Dose (Group 1)	Active comparator	Yellow Fever vaccine standard dose, 0.5mL. Receives: Biological: Yellow Fever Vaccine
Fractional dose (Group 2)	Experimental	Yellow Fever vaccine 1/5th standard dose, 0.1mL. Receives: Biological: Yellow Fever Vaccine
Fractional dose (Group 3)	Experimental	Yellow Fever vaccine 1/10th standard dose, 0.05mL. Receives: Biological: Yellow Fever Vaccine

What is being measured

The primary outcome is the main question the study is designed to answer.

Adverse Events
Rate of Adverse Events of fractional doses vs standard dose of YF-VAX.
Measured: Up to 28 days post vaccination
Neutralizing Antibody Response
For each group determine the PRNT50 neutralizing antibody response rate at the primary data point at post-vaccination day 28.
Measured: The primary data point is day 28 post-vaccination.

Secondary outcomes (1)

Viremia
Compare the rate of viremia by Reverse Transcription Polymerase Chain Reaction (RT-PCR) [copies/mL] of fractional doses vs standard dose.
Measured: First 14 days following vaccination.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

7 Jun 20212 Nov 2022

First posted16 May 2022
Study start7 Jun 2021
Primary completion2 Nov 2022
Study completion2 Nov 2022

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (16)Papers the sponsor has linked to this study.
Other trials for Yellow Fever Vaccination ReactionStudies 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: Health services research
Allocation: Randomised
Intervention model: Sequential
Masking: None (open label)
Enrolment: 88 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05374317
Sponsor's protocol ID: FY19-26
Status last verified: Mar 2026
First submitted: 28 Mar 2022
Last updated: 7 Apr 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No

Publications

Vasconcelos PF, Monath TP. Yellow Fever Remains a Potential Threat to Public Health. Vector Borne Zoonotic Dis. 2016 Aug;16(8):566-7. doi: 10.1089/vbz.2016.2031. Epub 2016 Jul 11.
PubMed 27400066
Monath TP, Woodall JP, Gubler DJ, Yuill TM, Mackenzie JS, Martins RM, Reiter P, Heymann DL. Yellow fever vaccine supply: a possible solution. Lancet. 2016 Apr 16;387(10028):1599-600. doi: 10.1016/S0140-6736(16)30195-7. Epub 2016 Apr 14. No abstract available.
PubMed 27116054
Calisher CH, Woodall JP. Yellow Fever-More a Policy and Planning Problem than a Biological One. Emerg Infect Dis. 2016 Oct;22(10):1859-60. doi: 10.3201/eid2210.160875. Epub 2016 Oct 15. No abstract available.
PubMed 27479749
Elachola H, Ditekemena J, Zhuo J, Gozzer E, Marchesini P, Rahman M, Sow S, Kattan RF, Memish ZA. Yellow fever outbreaks, vaccine shortages and the Hajj and Olympics: call for global vigilance. Lancet. 2016 Sep 17;388(10050):1155. doi: 10.1016/S0140-6736(16)31546-X. Epub 2016 Sep 5. No abstract available.
PubMed 27609407
Roukens AH, Vossen AC, Bredenbeek PJ, van Dissel JT, Visser LG. Intradermally administered yellow fever vaccine at reduced dose induces a protective immune response: a randomized controlled non-inferiority trial. PLoS One. 2008 Apr 23;3(4):e1993. doi: 10.1371/journal.pone.0001993.
PubMed 18431480
Slifka MK, Leung DY, Hammarlund E, Raue HP, Simpson EL, Tofte S, Baig-Lewis S, David G, Lynn H, Woolson R, Hata T, Milgrom H, Hanifin J. Transcutaneous yellow fever vaccination of subjects with or without atopic dermatitis. J Allergy Clin Immunol. 2014 Feb;133(2):439-47. doi: 10.1016/j.jaci.2013.10.037. Epub 2013 Dec 10.
PubMed 24331381
Campi-Azevedo AC, de Almeida Estevam P, Coelho-Dos-Reis JG, Peruhype-Magalhaes V, Villela-Rezende G, Quaresma PF, Maia Mde L, Farias RH, Camacho LA, Freire Mda S, Galler R, Yamamura AM, Almeida LF, Lima SM, Nogueira RM, Silva Sa GR, Hokama DA, de Carvalho R, Freire RA, Filho EP, Leal Mda L, Homma A, Teixeira-Carvalho A, Martins RM, Martins-Filho OA. Subdoses of 17DD yellow fever vaccine elicit equivalent virological/immunological kinetics timeline. BMC Infect Dis. 2014 Jul 15;14:391. doi: 10.1186/1471-2334-14-391.
PubMed 25022840
Wu JT, Peak CM, Leung GM, Lipsitch M. Fractional dosing of yellow fever vaccine to extend supply: a modelling study. Lancet. 2016 Dec 10;388(10062):2904-2911. doi: 10.1016/S0140-6736(16)31838-4. Epub 2016 Nov 10.
PubMed 27837923
Visser LG, Roukens AH. Modelling a way out of yellow fever. Lancet. 2016 Dec 10;388(10062):2847-2848. doi: 10.1016/S0140-6736(16)31330-7. Epub 2016 Nov 10. No abstract available.
PubMed 27837922
Casey RM, Harris JB, Ahuka-Mundeke S, Dixon MG, Kizito GM, Nsele PM, Umutesi G, Laven J, Kosoy O, Paluku G, Gueye AS, Hyde TB, Ewetola R, Sheria GKM, Muyembe-Tamfum JJ, Staples JE. Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report. N Engl J Med. 2019 Aug 1;381(5):444-454. doi: 10.1056/NEJMoa1710430. Epub 2018 Feb 14.
PubMed 29443626
Martins RM, Maia Mde L, Farias RH, Camacho LA, Freire MS, Galler R, Yamamura AM, Almeida LF, Lima SM, Nogueira RM, Sa GR, Hokama DA, de Carvalho R, Freire RA, Pereira Filho E, Leal Mda L, Homma A. 17DD yellow fever vaccine: a double blind, randomized clinical trial of immunogenicity and safety on a dose-response study. Hum Vaccin Immunother. 2013 Apr;9(4):879-88. doi: 10.4161/hv.22982. Epub 2013 Jan 30.
PubMed 23364472
Yellow fever vaccine: WHO position on the use of fractional doses - June 2017. Wkly Epidemiol Rec. 2017 Jun 23;92(25):345-50. No abstract available. English, French.
PubMed 28643507
Roukens AHE, Visser LG. Fractional-dose yellow fever vaccination: an expert review. J Travel Med. 2019 Sep 2;26(6):taz024. doi: 10.1093/jtm/taz024.
PubMed 30937437
Hepburn MJ, Kortepeter MG, Pittman PR, Boudreau EF, Mangiafico JA, Buck PA, Norris SL, Anderson EL. Neutralizing antibody response to booster vaccination with the 17d yellow fever vaccine. Vaccine. 2006 Apr 5;24(15):2843-9. doi: 10.1016/j.vaccine.2005.12.055. Epub 2006 Jan 18.
PubMed 16494976
Hotez PJ, LaBeaud AD. Yellow Jack's Potential Return to the American South. N Engl J Med. 2023 Oct 19;389(16):1445-1447. doi: 10.1056/NEJMp2308420. Epub 2023 Oct 14. No abstract available.
PubMed 37843124

Study at a glance

From the registry record, last updated by the sponsor on 7 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: An Exploratory, Pilot Study of the Safety and Immunogenicity of Reduced Doses of the US Yellow Fever Vaccine
ClinicalTrials.gov ID: NCT05374317
Acronym / sponsor ID: FY19-26
Conditions: Yellow Fever Vaccination Reaction
Phase: Phase 4
Study type: Interventional
Recruitment status: Completed
Enrolment: 88 participants (actual)
Lead sponsor: US Army Medical Research Institute of Infectious DiseasesUS federal agency
Study start: 7 Jun 2021 (actual)
Primary completion: 2 Nov 2022 (actual)
Study completion: 2 Nov 2022 (actual)
First posted: 16 May 2022 (actual)
Results: Posted 7 Apr 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Health services research
Allocation: Randomised
Intervention model: Sequential
Masking: None (open label)
Number of arms: 3

Arm	Type	Receives
Standard Dose (Group 1)	Active comparator	Biological: Yellow Fever VaccineYellow Fever vaccine standard dose, 0.5mL.
Fractional dose (Group 2)	Experimental	Biological: Yellow Fever VaccineYellow Fever vaccine 1/5th standard dose, 0.1mL.
Fractional dose (Group 3)	Experimental	Biological: Yellow Fever VaccineYellow Fever vaccine 1/10th standard dose, 0.05mL.

Who may qualify

Ages: 18 to 50 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (6 listed)

Males and Females 18 to 50 years of age.
In good health, as determined by pertinent medical history, physical examination, vital signs, and clinical safety laboratory evaluations.
Female of child bearing potential: Has a negative pregnancy test and is willing to use a reliable form of contraception for the duration of the study after vaccination.
Negative human immunodeficiency virus (HIV) antibody screen, seronegative for hepatitis B surface antigen (HBsAg) and hepatitis C antibody (following HIV and hepatitis testing, subjects will be provided with counseling and referral for health care if any test is positive).
Ability to comprehend and a willingness to sign an informed consent, which includes the Health Insurance Portability and Accountability Act (HIPAA) Authorization, and a separate consent form for HIV testing.

Key exclusion criteria (10 listed)

Receipt of any other investigational vaccine or investigational drug within 28 days prior to or after vaccination with YF-VAX® vaccine.
Have had any known flavivirus disease or receipt of any flavivirus vaccine, licensed or investigational at any time; in addition to any yellow fever vaccine, these include; Japanese Encephalitis (JE), St. Louis Encephalitis, Tick Borne Encephalitis (TBE), West Nile, Dengue, Zika virus
Anticipates receipt of any other vaccine within 28 days of YF-VAX®. Influenza vaccination will be permitted but not within 14 days of YF-VAX®.
Acute or chronic medical conditions, or medications that, in the Principal Investigator's (PI) opinion, would impair the subject's ability to respond to vaccination.
Hypersensitivity to any vaccine, eggs or egg products, or allergy to any component of the YF-VAX® (sorbitol, gelatin) or latex.

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
Yellow Fever VaccineAlso: YF-VAXAdministered subcutaneously once.	Biological	Fractional dose (Group 2), Fractional dose (Group 3), Standard Dose (Group 1)

Primary outcome

Adverse Events
Time frame: Up to 28 days post vaccination
Rate of Adverse Events of fractional doses vs standard dose of YF-VAX.
Neutralizing Antibody Response
Time frame: The primary data point is day 28 post-vaccination.
For each group determine the PRNT50 neutralizing antibody response rate at the primary data point at post-vaccination day 28.

1 secondary outcome

Viremia
Time frame: First 14 days following vaccination.

Results and safety

Results posted to the registry on 7 Apr 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Standard Dose (Group 1)	29	23
Fractional Dose (Group 2)	30	25
Fractional Dose (Group 3)	29	24

Primary outcome: Adverse Events

Time frame: Up to 28 days post vaccination. Count of participants. Unit: Participants

Measure	Standard Dose (Group 1) n = 29	Fractional Dose (Group 2) n = 30	Fractional Dose (Group 3) n = 29
Value	26	27	28

Population analysed: All participants who received a single dose of vaccine.

Primary outcome: Neutralizing Antibody Response

Time frame: The primary data point is day 28 post-vaccination.. Count of participants. Unit: Participants

Measure	Standard Dose (Group 1) n = 27	Fractional Dose (Group 2) n = 29	Fractional Dose (Group 3) n = 28
Value	26	27	28

Population analysed: All participants who received a single dose of vaccine and complied with day 28 study visit.

1 secondary outcome is reported in the full results.

Adverse events

Time frame: Adverse Events collected Up to one year following vaccination.. Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Standard Dose (Group 1)	1 of 29 (3.4%)	15 of 29 (51.7%)	0 of 29
Fractional Dose (Group 2)	0 of 30 (0%)	11 of 30 (36.7%)	0 of 30
Fractional Dose (Group 3)	0 of 29 (0%)	7 of 29 (24.1%)	0 of 29

Limitations and caveats (from the sponsor): This was a pilot study to establish proof of concept.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 7 Apr 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Background: PubMed 27400066Vasconcelos PF, Monath TP. Yellow Fever Remains a Potential Threat to Public Health. Vector Borne Zoonotic Dis. 2016 Aug;16(8):566-7. doi: 10.1089/vbz.2016.2031. Epub 2016 Jul 11.
Background: PubMed 27116054Monath TP, Woodall JP, Gubler DJ, Yuill TM, Mackenzie JS, Martins RM, Reiter P, Heymann DL. Yellow fever vaccine supply: a possible solution. Lancet. 2016 Apr 16;387(10028):1599-600. doi: 10.1016/S0140-6736(16)30195-7. Epub 2016 Apr 14. No abstract available.
Background: PubMed 27479749Calisher CH, Woodall JP. Yellow Fever-More a Policy and Planning Problem than a Biological One. Emerg Infect Dis. 2016 Oct;22(10):1859-60. doi: 10.3201/eid2210.160875. Epub 2016 Oct 15. No abstract available.
Background: PubMed 27609407Elachola H, Ditekemena J, Zhuo J, Gozzer E, Marchesini P, Rahman M, Sow S, Kattan RF, Memish ZA. Yellow fever outbreaks, vaccine shortages and the Hajj and Olympics: call for global vigilance. Lancet. 2016 Sep 17;388(10050):1155. doi: 10.1016/S0140-6736(16)31546-X. Epub 2016 Sep 5. No abstract available.
Background: PubMed 18431480Roukens AH, Vossen AC, Bredenbeek PJ, van Dissel JT, Visser LG. Intradermally administered yellow fever vaccine at reduced dose induces a protective immune response: a randomized controlled non-inferiority trial. PLoS One. 2008 Apr 23;3(4):e1993. doi: 10.1371/journal.pone.0001993.
Background: PubMed 24331381Slifka MK, Leung DY, Hammarlund E, Raue HP, Simpson EL, Tofte S, Baig-Lewis S, David G, Lynn H, Woolson R, Hata T, Milgrom H, Hanifin J. Transcutaneous yellow fever vaccination of subjects with or without atopic dermatitis. J Allergy Clin Immunol. 2014 Feb;133(2):439-47. doi: 10.1016/j.jaci.2013.10.037. Epub 2013 Dec 10.
Background: PubMed 25022840Campi-Azevedo AC, de Almeida Estevam P, Coelho-Dos-Reis JG, Peruhype-Magalhaes V, Villela-Rezende G, Quaresma PF, Maia Mde L, Farias RH, Camacho LA, Freire Mda S, Galler R, Yamamura AM, Almeida LF, Lima SM, Nogueira RM, Silva Sa GR, Hokama DA, de Carvalho R, Freire RA, Filho EP, Leal Mda L, Homma A, Teixeira-Carvalho A, Martins RM, Martins-Filho OA. Subdoses of 17DD yellow fever vaccine elicit equivalent virological/immunological kinetics timeline. BMC Infect Dis. 2014 Jul 15;14:391. doi: 10.1186/1471-2334-14-391.
Background: PubMed 27837923Wu JT, Peak CM, Leung GM, Lipsitch M. Fractional dosing of yellow fever vaccine to extend supply: a modelling study. Lancet. 2016 Dec 10;388(10062):2904-2911. doi: 10.1016/S0140-6736(16)31838-4. Epub 2016 Nov 10.
Background: PubMed 27837922Visser LG, Roukens AH. Modelling a way out of yellow fever. Lancet. 2016 Dec 10;388(10062):2847-2848. doi: 10.1016/S0140-6736(16)31330-7. Epub 2016 Nov 10. No abstract available.
Background: PubMed 29443626Casey RM, Harris JB, Ahuka-Mundeke S, Dixon MG, Kizito GM, Nsele PM, Umutesi G, Laven J, Kosoy O, Paluku G, Gueye AS, Hyde TB, Ewetola R, Sheria GKM, Muyembe-Tamfum JJ, Staples JE. Immunogenicity of Fractional-Dose Vaccine during a Yellow Fever Outbreak - Final Report. N Engl J Med. 2019 Aug 1;381(5):444-454. doi: 10.1056/NEJMoa1710430. Epub 2018 Feb 14.
Background: PubMed 23364472Martins RM, Maia Mde L, Farias RH, Camacho LA, Freire MS, Galler R, Yamamura AM, Almeida LF, Lima SM, Nogueira RM, Sa GR, Hokama DA, de Carvalho R, Freire RA, Pereira Filho E, Leal Mda L, Homma A. 17DD yellow fever vaccine: a double blind, randomized clinical trial of immunogenicity and safety on a dose-response study. Hum Vaccin Immunother. 2013 Apr;9(4):879-88. doi: 10.4161/hv.22982. Epub 2013 Jan 30.
Background: PubMed 28643507Yellow fever vaccine: WHO position on the use of fractional doses - June 2017. Wkly Epidemiol Rec. 2017 Jun 23;92(25):345-50. No abstract available. English, French.
Individual participant dataSharing planned: No

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.

Phillip R Pittman, M.D., M.P.H. principal investigator

US Army Medical Research Institute of Infectious Diseases

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 Yellow Fever Vaccine in people with Yellow Fever Vaccination Reaction, run by US Army Medical Research Institute of Infectious Diseases 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 6 inclusion and 10 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 7 Apr 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?

Yes. Results are posted in the registry (first posted 7 Apr 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Adverse Events (time frame: Up to 28 days post vaccination). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05374317, which also lists 16 linked publications.

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 7 Apr 2026.