CompletedNCT00283283Updated Feb 12, 2021Results posted

Comparison of Full-dose Flu Vaccine to Half-dose Flu Vaccine

A Phase 2 interventional study of Fluzone® (Aventis Pasteur inactivated influenza vaccine) in Influenza, sponsored by U.S. Army Medical Research and Development Command. Completed at 2 sites in United States. Open to participants aged 18 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2021-02-12.

Sponsored by U.S. Army Medical Research and Development Command · Phase 2, Interventional, and Prevention

From the registry’s dates

Registered 1 year 2 months after the study started (first participant enrolled Nov 2004, registered Jan 2006).

Phase: Phase 2
Study type: Interventional
Enrollment: 1,316
Allocation: Randomized
Ages: 18 Years to 64 Years
Sex: All

Study summary

This study compared full-dose Flu vaccine to half-dose Flu-vaccine during the 2004-2005 flu season.

Read the detailed description

This was a Phase II prospective, single-blind to dose, randomized study that compared the immunogenicity of subjects receiving half-dose Fluzone® compared to full-dose Fluzone®, 2004-2005 formulation. 1440 healthy subjects, ages 18-64 years old and not currently indicated for influenza vaccination under the interim ACIP guidelines, were divided into 8 strata based on age, gender, and previous exposure to influenza vaccine, and randomized to receive either half-dose (0.25mL) Fluzone® or full-dose (0.5mL) Fluzone® by intramuscular injection into the deltoid muscle.

Conditions studied

Influenza

Browse trials for

Influenza, Human 2,214

Keywords

Influenza

In context

Influenza, Human

2,214 studies on the registry are indexed under Influenza, Human; 163 are open to participants now.

This study's enrollment of 1,316 is above the median of 238 across 1,853 interventional studies indexed under Influenza, Human.

Browse Influenza, Human studies →

Lead sponsor

U.S. Army Medical Research and Development Command is the lead sponsor of 151 studies on the registry; 8 are open to participants now.

Of its 23 completed or terminated interventional studies of FDA-regulated products, 16 (70%) have results posted.

Counted across the registry records on this site, refreshed daily.

Who can participate

Ages eligible: 18 Years to 64 Years
Sexes eligible: All
Accepts healthy volunteers: Yes

Inclusion criteria

Able to understand and comply with all study procedures including availability for all study visits and follow up surveys within 6 months following study enrollment.
DEERS eligible beneficiaries eligible for influenza vaccination and able to give informed consent.
Age 18-49
- Patients presenting to travel clinic with no exclusion criteria;
- Household contacts and out-of-home caretakers of infants from 6-23 months of age;
- Hospital and/or employees providing service to the public who are not eligible for the post-October 5th recommendations for priority immunization;
- DOD employees eligible for influenza vaccination prior to October 5th but excluded in the post October 5th guidelines;
- People living in dormitories or under other crowded conditions, to prevent outbreaks;
Ages 50-64 years of age who are not eligible for the post-October 5th recommendations for priority immunization and with no standard of care contraindications to vaccination.
Eligible in the Department of Defense for influenza vaccination

Exclusion criteria

Exclusion Criteria:

all children aged \< 18 years (includes children aged 6 months-18 years on chronic aspirin therapy);
adults aged >65 years;
persons aged 2-64 years with underlying chronic medical conditions:
- includes persons with chronic cardiac or pulmonary disease, diabetes mellitus, hemoglobinopathy, or immunosuppressive illness;
- any acute or chronic condition that, in the opinion of the investigator, would render vaccination unsafe or interfere with the evaluation of response.
use of experimental vaccines or medications within 30 days of study entry;
receipt of parenteral immunoglobulin within 60 days of study entry;
all women who will be pregnant during the influenza season;
residents of nursing homes and long-term care facilities;
health-care workers involved in direct patient care and included in DOD priority 1; and;
military recruits;
out-of-home caregivers and household contacts of children aged \<6 months.
Anyone with clinical contraindications for receiving the inactivated influenza vaccine such as a history of severe allergic reaction to prior influenza vaccinations, severe allergy to egg and/or egg proteins and gelatin.
DOD Priority 1: Deployed or deploying (with orders) service members and others designated as critical to national defense.
DOD Priority 2: Medically high risk in accordance with ACIP guidelines (includes health-care workers with direct patient contact)
Any acute or chronic condition that, in the opinion of the investigator or her provider designee would render vaccination unsafe or interfere with the evaluation of the response.

Study design

Phase: Phase 2
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Single (Participant)
Enrollment: 1,316 participants (actual)

Study arms

Experimental
Male, Age 18 -49, Full Dose
0.5ml, 15µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinin antigen per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Male, Age 50 -64, Half Dose
0.25ml, 7.5µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinia per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Female, Age 18 - 49, Full Dose
0.5ml, 15µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinin antigen per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Female, Age 18 - 49, Half Dose
0.25ml, 7.5µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinia per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Male, Age 18 - 49, Half Dose
0.25ml, 7.5µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinia per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Male, Age 50 -64, Full Dose
0.5ml, 15µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinin antigen per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Female, Age 50 -64, Full Dose
0.5ml, 15µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinin antigen per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)
Experimental
Female, Age 50 -64, Half Dose
0.25ml, 7.5µg Fluzone® (Aventis Pasteur inactivated influenza vaccine) hemagglutinin antigen per strain
Biological: Fluzone® (Aventis Pasteur inactivated influenza vaccine)

Interventions

BiologicalFluzone® (Aventis Pasteur inactivated influenza vaccine)
A/H1N1, A/New Caledonia/20/99; A/H3N2, A/Fujian/411/2002; B, B/Shanghai/361/2002

What researchers measure

Primary outcomes

Immune Response: Age 18-49
Immune response as measured by viral strain specific hemaggluttination inhibition (HAI) antibody levels for subjects ages 18-49
Time frame: 21 days post-vaccincation
Immune Response: Age 50-64
Immune response as measured by viral strain specific hemaggluttination inhibition (HAI) antibody levels for subjects ages 50-64
Time frame: 21 days post-vaccincation

Secondary outcomes

Medical Events: Unsolicited Adverse Events
Assessed through following subjects' recording of oral body temperature, completion of a 21-day symptom diary; subjects' completion of longer-term follow-up surveys to track respiratory symptoms; and a review of the Defense Medical Surveillance System (DMSS) hospitalization and outpatient medical visits database in order to track ICD-9 codes relevant to flu-like illness.
Time frame: 3 - 6 months following vaccination

Other outcomes

Race/Ethnicity Baseline Measure
Race/ethnicity data was only collected by age and cannot be separated out by dose as per the other Baseline Measures
Time frame: Enrollment Day

Results

Posted Jun 19, 2020

Participant flow

Study participants were recruited at the Walter Reed Army Medical Center Allergy-Immunization Clinic, the Fort Belvoir DeWitt Allergy-Immunization Clinic and the Pentagon Health Clinic during the annual influenza immunization program.

Participant flow — Overall Study
Milestone	Full Dose, Age 18-49	Half Dose, Age 18-49	Full Dose, Age 50-64	Half Dose, Age 50-64
Started	274	284	280	276
Completed	274	284	280	276
Not completed	0	0	0	0

Outcome measures

PrimaryImmune Response: Age 18-49

Immune response as measured by viral strain specific hemaggluttination inhibition (HAI) antibody levels for subjects ages 18-49

Time frame:: 21 days post-vaccincation
Reported as:: Geometric mean · Anti-body response (GMT)

Immune Response: Age 18-49
Anti-body response (GMT)	Age 18 - 49, Full Dose	Age 18 - 49, Half Dose
H1N1 - GMT	28.8 (25.2 to 32.8)	21.3 (18.9 to 24.0)
H3N2 - GMT	55.2 (48.7 to 62.5)	45.0 (39.7 to 50.9)
B - GMT	69.6 (61.4 to 78.9)	54.8 (49.1 to 61.2)

PrimaryImmune Response: Age 50-64

Immune response as measured by viral strain specific hemaggluttination inhibition (HAI) antibody levels for subjects ages 50-64

Time frame:: 21 days post-vaccincation
Reported as:: Geometric mean · Anti-body response (GMT)

Immune Response: Age 50-64
Anti-body response (GMT)	Age 50 - 64, Full Dose	Age 50 - 64, Half Dose
H1N1 - GMT	21.4 (18.6 to 24.7)	14.2 (12.7 to 15.9)
H3N2 - GMT	59.0 (51.4 to 67.8)	39.1 (34.3 to 44.6)
B - GMT	52.1 (45.5 to 59.8)	36.8 (32.4 to 41.9)

SecondaryMedical Events: Unsolicited Adverse Events

Assessed through following subjects' recording of oral body temperature, completion of a 21-day symptom diary; subjects' completion of longer-term follow-up surveys to track respiratory symptoms; and a review of the Defense Medical Surveillance System (DMSS) hospitalization and outpatient medical visits database in order to track ICD-9 codes relevant to flu-like illness.

Time frame:: 3 - 6 months following vaccination
Reported as:: Number · Adverse events

Medical Events: Unsolicited Adverse Events
Adverse events	Mild	Moderate	Severe, Able to Work	Severe, Lost Productivity	No Events
Body as a Whole	0	6	1	3	1193
Cardiovascular System	2	2	0	0	1199
Digestive Sytem	12	3	2	4	1182
Hematological and Lymphatic System	2	0	1	0	1200
Musculoskeletal System	6	5	1	1	1190
Respiratory System	10	18	5	3	1167
Skin and Appendages	14	8	1	0	1180
Special Senses	2	2	0	1	1198
Urogenital System	0	4	0	0	1199
Symptions in Arm Given Shot	13	1	0	0	1189
Headache	0	2	1	1	1199

Other pre-specifiedRace/Ethnicity Baseline Measure

Race/ethnicity data was only collected by age and cannot be separated out by dose as per the other Baseline Measures

Time frame:: Enrollment Day
Reported as:: Count of participants · Participants

Race/Ethnicity Baseline Measure
Participants	Aged 18-49 y (n=558)	Aged 50-64 y (n=556)
White	454	491
African American	54	46
Hispanic	16	6
Asian	14	7
Other/unknown	10	6

Adverse events

Collected over 3 - 6 months following vaccination. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
Full Dose	0/554 (0%)	2/554 (0.4%)	18/554 (3.2%)
Half Dose	0/556 (0%)	1/556 (0.2%)	17/556 (3.1%)

Most frequent serious events

Most frequent serious events
Event	Full Dose	Half Dose
Melanoma exisedSurgical and medical procedures	1/554	0/556
Breast cancerNeoplasms benign, malignant and unspecified (incl cysts and polyps)	1/554	0/556
Carotid endarterectomeyCardiac disorders	0/554	1/556

Most frequent other events

Showing 10 of 27

Most frequent other events
Event	Full Dose	Half Dose
Brusing at injection siteInjury, poisoning and procedural complications	4/554	1/556
Injection site sorenessInjury, poisoning and procedural complications	3/554	2/556
DiarrheaGastrointestinal disorders	2/554	0/556
Aching at injection siteInjury, poisoning and procedural complications	1/554	0/556
Arm sore at injection siteInjury, poisoning and procedural complications	1/554	0/556
Fever, chills, flu-like symptomsGeneral disorders	1/554	0/556
Irritable bowel syndromeGastrointestinal disorders	1/554	0/556
Itching, distil to injection siteInjury, poisoning and procedural complications	1/554	1/556
Outbreak of HSV on face, also nasal lesionsInfections and infestations	1/554	0/556
Pain in right antecubital area after venipunctureInjury, poisoning and procedural complications	1/554	0/556

Baseline characteristics

FCSR didn't report baseline demographics per arm they were presented by age group.

Age, Customized
Age, Customized(years)	Full Dose, Age 18-49	Half Dose, Age 18-49	Full Dose, Age 50-64	Half Dose, Age 50-64	Total
Number	274	284	280	276	1114

Sex: Female, Male
Sex: Female, Male(Participants)	Full Dose, Age 18-49	Half Dose, Age 18-49	Full Dose, Age 50-64	Half Dose, Age 50-64	Total
Female	126	121	119	118	484
Male	148	163	161	158	630

Region of Enrollment
Region of Enrollment(participants)	Full Dose, Age 18-49	Half Dose, Age 18-49	Full Dose, Age 50-64	Half Dose, Age 50-64	Total
United States	274	284	280	276	1114

Study locations

2 sites

Pentagon
Washington, District of Columbia 20050, United States
Walter Reed Army Medical Center
Washington, District of Columbia 20307, United States

References and documents

Publications

Engler RJ, Nelson MR, Klote MM, VanRaden MJ, Huang CY, Cox NJ, Klimov A, Keitel WA, Nichol KL, Carr WW, Treanor JJ; Walter Reed Health Care System Influenza Vaccine Consortium. Half- vs full-dose trivalent inactivated influenza vaccine (2004-2005): age, dose, and sex effects on immune responses. Arch Intern Med. 2008 Dec 8;168(22):2405-14. doi: 10.1001/archinternmed.2008.513. PubMed 19064822 ↗

Individual participant data

Plan to share: No

Updates

Tracking since Sep 25, 2026

No changes since tracking began. The registry record was last updated on Feb 12, 2021, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT00283283
Lead sponsor: U.S. Army Medical Research and Development Command
Collaborators: Walter Reed Army Medical Center, United States Army Medical Materiel Development Activity, Centers for Disease Control and Prevention, Uniformed Services University of the Health Sciences, Walter Reed Army Institute of Research (WRAIR), U.S. Air Force Office of the Surgeon General
Responsible party: Sponsor
First posted: Jan 27, 2006
Start date: Nov 2004
Primary completion: Nov 2004
Completion: May 2006
Results posted: Jun 19, 2020
Last update: Feb 12, 2021

Study contacts

Renata J Engler, M.D

principal investigator · Walter Reed Army Medical Center

Oversight

Data monitoring committee: No

View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Feb 2021. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Other studies in this condition

Influenza, Human→

Other studies from this sponsor

U.S. Army Medical Research and Development Command

Start the discussion