CompletedNCT00053495Updated Mar 18, 2024Results posted

Effect of Dose, Safety, Tolerability of a New Smallpox Vaccine in Adults Without Previous Smallpox Vaccination

A Phase 2 interventional study of Vaccinia virus: ACAM2000 smallpox vaccine and vaccinia virus (calf lymph): Dryvax in Smallpox, sponsored by Emergent BioSolutions. Completed at 4 sites in United States. Open to participants aged 18 Years to 29 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-03-18.

Sponsored by Emergent BioSolutions · Phase 2, Interventional, and Prevention

Phase: Phase 2
Study type: Interventional
Enrollment: 353
Allocation: Randomized
Ages: 18 Years to 29 Years
Sex: All

Study summary

The purpose of this study is to examine the safety and the effectiveness of a new vaccine for the prevention of the disease, smallpox.

Read the detailed description

The objective of this study is to determine the minimum dose of ACAM2000 that is calculated to produce a major cutaneous reaction in at least 90% of a population of healthy adults 18-29 years of age and naïve to smallpox vaccine. Specifically, the objectives of this study are to:

Compare the safety and tolerability of four dose levels of ACAM2000 and a standard dose of Dryvax® in healthy adults 18-29 years of age and naïve to smallpox vaccine. Safety and tolerability will be determined by examination of the local cutaneous reaction, adverse events, physical examinations, vital signs, structured interviews, and laboratory analysis.
Determine the immunogenicity of four dose levels of ACAM2000 and a standard dose of Dryvax® in healthy adults 18-29 years of age by comparing:
1. the proportion of subjects at each dose level who develop a major cutaneous reaction;
2. the proportion of subjects in each treatment group who develop neutralizing antibodies, including the fold-increase in antibody titer between Baseline and Day 30 sera; and the geometric mean vaccinia neutralizing antibody titer on Day 30.
Determine the minimum dose of ACAM2000 that is calculated to produce a major cutaneous reaction in at least 90% of a population of healthy adults 18-29 years of age and naïve to smallpox vaccine.

Conditions studied

Smallpox

Browse trials for

Smallpox 73

Keywords

Smallpox

In context

Smallpox

73 studies on the registry are indexed under Smallpox; 5 are open to participants now.

This study's enrollment of 353 is above the median of 150 across 61 interventional studies indexed under Smallpox.

Browse Smallpox studies →

Lead sponsor

Emergent BioSolutions is the lead sponsor of 47 studies on the registry; 7 are open to participants now.

Of its 11 completed or terminated interventional studies of FDA-regulated products, 7 (64%) have results posted.

Browse Emergent BioSolutions studies →

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

Who can participate

Ages eligible: 18 Years to 29 Years
Sexes eligible: All
Accepts healthy volunteers: Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

females must not be pregnant, lactating and must agree to use an effective form of for the 30 days following vaccination or unable to bear children.
agree to be available for the entire study and agree to comply with all requirements.

Exclusion criteria

Exclusion criteria:

military service prior to 1989.
history of previous smallpox vaccination.
children 1 year of age or younger in the household or be in close contact
smallpox vaccination within ten years
known or suspected (HIV) infection, primary immunodeficiency disorder, leukemia, lymphoma, or current radiation treatment or use of or anti-neoplastic drugs or have a household member or intimate contact with the conditions listed above.
renal disease
current or past history of eczema or a household member or direct contact who has eczema.
known allergy or past allergic reactions to latex gloves or to antibiotics which include neomycin, streptomycin, chlortetracycline, and polymyxin B
known allergy or past allergic reaction to blood products.
known allergy to cidofovir or sulfa-containing drugs.
history of allergic phenomena following smallpox vaccination in the past, including urticaria, erythema multiforme, or Stevens-Johnson syndrome.
transfusion of blood or treatment with any blood product.
current or history of drug or alcohol abuse
inoculation with any other or participating in another drug or vaccine trial within 30 days of enrollment.

Terms in these criteria, in plain language(4)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

Study design

Phase: Phase 2
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel assignment
Masking: Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment: 353 participants (actual)

Study arms

Experimental
Group 1: ACAM2000 Dose 1
Participants will receive a single dose of ACAM2000 smallpox vaccine, 1.0x10-8th plaque-forming units (PFU)/mL on Day 0.
Biological: Vaccinia virus: ACAM2000 smallpox vaccine
Experimental
Group 2: ACAM2000 Dose 2
Participants will receive a single dose of ACAM2000 smallpox vaccine, 2.0x10-8th plaque-forming units/mL on Day 0.
Biological: Vaccinia virus: ACAM2000 smallpox vaccine
Experimental
Group 3: ACAM2000 Dose 3
Participants will receive a single dose of ACAM2000 smallpox vaccine, 1.0x10-7th plaque-forming units/mL on Day 0
Biological: Vaccinia virus: ACAM2000 smallpox vaccine
Experimental
Group 4: ACAM2000 Dose 4
Participants received a single dose of ACAM2000 smallpox vaccine, 5.0x10-6th plaque-forming units/mL on Day 0
Biological: Vaccinia virus: ACAM2000 smallpox vaccine
Active comparator
Group 5: Dryvax® Vaccine
Participants will receive a single dose of Dryvax® smallpox vaccine, 1.0x10-8th plaque-forming units/mL on Day 0
Biological: vaccinia virus (calf lymph): Dryvax

Interventions

BiologicalVaccinia virus: ACAM2000 smallpox vaccine
Group 1 dose: 1.0x10-8th PFU/ml Group 2 dose: 2.0x10-8th PFU/ml Group 3 dose: 1.0x10-7th PFU/ml Group 4 dose: 5.0x10-6th PFU/ml
Biologicalvaccinia virus (calf lymph): Dryvax
Group 5 dose: 1.0x10-8th PFU/ml
Also known as: Dryvax®

What researchers measure

Primary outcomes

Number of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
The severity of each reported adverse event was classified by the investigator according to the following definitions. None - no symptom; Mild - awareness of sign or symptoms, but easily tolerated; Moderate - discomfort enough to cause interference with usual activity; and Severe - incapacitating with inability to work or perform usual activity.
Time frame: Days 0 to 30 post-vaccination
Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame: Day 30 post-vaccination
Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame: Day 30 post-vaccination

Other outcomes

Number of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame: Days 0 to 30 post-vaccination
Clinical Chemistry Parameters (Aspartate Aminotransaminase and Alanine Aminotransferase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame: Days 0 (baseline) and 15 post-vaccination
Clinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Time frame: Days 0 (baseline) and 15 post-vaccination
Selected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame: Days 0 (baseline) and 15 post-vaccination
Selected Hematology Parameters (Red Blood Count and Platelets) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.
Time frame: Days 0 (baseline) and 15 post-vaccination

Results

Posted Feb 11, 2011

Participant flow

Participants were enrolled from 10 January 2003 to 14 April 2003 in 4 medical centers in the US.

Participant flow — Overall Study
Milestone	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Started	51	101	101	51	49
Completed	51	101	101	51	49
Not completed	0	0	0	0	0

Outcome measures

PrimaryNumber of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

The severity of each reported adverse event was classified by the investigator according to the following definitions. None - no symptom; Mild - awareness of sign or symptoms, but easily tolerated; Moderate - discomfort enough to cause interference with usual activity; and Severe - incapacitating with inability to work or perform usual activity.

Time frame:: Days 0 to 30 post-vaccination
Reported as:: Number · Participants

Number of Participants Reporting Adverse Events of Severe Intensity Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
Participants	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Lymph Node Pain	2	4	3	4	2
Lymphadenopathy	0	0	0	1	0
Diarrhea Not Otherwise Specified	1	0	0	0	0
Nausea	1	0	0	0	0
Vomiting Not Otherwise Specified	1	0	0	0	0
Injection Site Erythema	1	6	14	11	15
Injection Site Swelling	0	0	1	1	0
Injection Site Pruritus	0	0	1	0	1
Fatigue	0	0	1	0	0
Injection Site Pain	0	0	1	0	0
Dehydration	0	0	1	0	0
Myalgia	0	0	0	1	0
Headache Not Otherwise Specified	1	0	4	1	0
Pregnancy Not Otherwise Specified	0	1	0	1	0
Dysuria	1	0	0	0	0

PrimaryNeutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.

Time frame:: Day 30 post-vaccination
Reported as:: Mean · PRNT50 Titers

Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
PRNT50 Titers	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Neutralizing Antibody Response Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.	212 ± 536.4	278 ± 581.6	425 ± 947.4	582 ± 1129.3	1515 ± 6019.4

Other pre-specifiedNumber of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.

Time frame:: Days 0 to 30 post-vaccination
Reported as:: Number · Participants

Number of Participants With Treatment-Emergent Rash Events Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Participants	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Rash Not Otherwise Specified	3	10	9	5	7
Rash Pruritic	0	1	0	0	0
Rash Pustular	0	1	0	0	1
Application Site Rash	0	1	1	3	2
Injection Site Rash	0	0	1	0	1
Any Rash Event	3	11	10	7	10

Other pre-specifiedClinical Chemistry Parameters (Aspartate Aminotransaminase and Alanine Aminotransferase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

Time frame:: Days 0 (baseline) and 15 post-vaccination
Reported as:: Mean · IU/L

Clinical Chemistry Parameters (Aspartate Aminotransaminase and Alanine Aminotransferase) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
IU/L	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Aspartate Aminotransferase (Baseline)	21 ± 7.4	21 ± 5.9	22 ± 7.1	23 ± 7.1	20 ± 5.8
Aspartate Aminotransferase (Day 15)	23 ± 10.5	21 ± 7.7	22 ± 7.5	21 ± 6.3	22 ± 6.8
Alanine Aminotransferase (Baseline)	32 ± 15.0	32 ± 16.2	33 ± 17.4	36 ± 18.5	31 ± 16.8
Alanine Aminotransferase (Day 15)	33 ± 15.4	32 ± 17.5	33 ± 16.6	34 ± 16.2	33 ± 17.9

Other pre-specifiedClinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine

Time frame:: Days 0 (baseline) and 15 post-vaccination
Reported as:: Mean · mg/dL

Clinical Chemistry Parameters (Creatinine and Glucose) at Baseline and Day 15 Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine
mg/dL	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Creatinine (Baseline)	0.97 ± 0.147	0.96 ± 0.153	0.98 ± 0.181	0.97 ± 0.171	0.97 ± 0.158
Creatinine (Day 15)	0.98 ± 0.149	0.98 ± 0.142	0.98 ± 0.169	1.00 ± 0.144	1.00 ± 0.163
Glucose (Baseline)	85 ± 7.3	84 ± 9.8	86 ± 7.4	86 ± 8.3	87 ± 18.6
Glucose (Day 15)	83 ± 14.2	86 ± 14.6	86 ± 10.6	87 ± 13.2	88 ± 21.4

PrimaryParticipants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.

Time frame:: Day 30 post-vaccination
Reported as:: Number · Participants

Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.
Participants	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Participants With ≥ 4-fold Increase in Plaque-Reduction Neutralization Test (PRNT50) Titers Post-vaccination With ACAM2000 or Dryvax® Smallpox Vaccine.	28	73	84	48	47

Other pre-specifiedSelected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.

Time frame:: Days 0 (baseline) and 15 post-vaccination
Reported as:: Mean · Percentage (%)

Selected Hematology Parameters (Hematocrit, Lymphocyte, and Eosinophil) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.
Percentage (%)	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Hematocrit (Baseline)	43.7 ± 4.20	43.2 ± 3.71	43.2 ± 4.44	44.2 ± 3.29	44.1 ± 3.54
Hematocrit (Day 15)	42.8 ± 3.74	42.3 ± 3.59	42.7 ± 3.21	43.2 ± 2.55	43.1 ± 3.13
Lymphocytes (Baseline)	30.6 ± 8.26	31.5 ± 8.33	30.7 ± 7.00	29.6 ± 7.45	31.6 ± 7.99
Lymphocytes (Day 15)	33.9 ± 8.62	34.0 ± 7.41	34.7 ± 7.93	33.9 ± 6.83	33.8 ± 7.58
Eosinophils (Baseline)	2.5 ± 1.61	2.5 ± 1.95	2.4 ± 1.69	2.3 ± 1.42	2.4 ± 1.72
Eosinophils (Day 15)	2.8 ± 2.07	2.8 ± 2.11	2.6 ± 1.65	2.7 ± 1.42	2.7 ± 1.61

Other pre-specifiedSelected Hematology Parameters (Red Blood Count and Platelets) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.

Time frame:: Days 0 (baseline) and 15 post-vaccination
Reported as:: Mean · x10-6th/μL

Selected Hematology Parameters (Red Blood Count and Platelets) at Baseline and on Day 15 in Participants Vaccinated With ACAM2000 or Dryvax® Smallpox Vaccine.
x10-6th/μL	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Red Blood Cell Count (Baseline)	5.1 ± 0.53	5.0 ± 0.47	5.1 ± 0.44	5.1 ± 0.45	5.1 ± 0.44
Red Blood Cell Count (Day 15)	5.0 ± 0.50	4.9 ± 0.44	5.0 ± 0.39	5.0 ± 0.37	5.0 ± 0.38
Platelets (Baseline)	274 ± 64.0	282 ± 60.1	281 ± 68.1	274 ± 52.4	267 ± 51.6
Platelets (Day 15)	284 ± 58.6	280 ± 57.7	281 ± 65.1	284 ± 59.3	285 ± 52.1

Adverse events

Collected over Adverse events data were collected from the day of vaccination for up to 6 months post-vaccination.. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
Group	Deaths	Serious	Other
ACAM2000 Dose 1	—	1/51 (2%)	51/51 (100%)
ACAM2000 Dose 2	—	1/101 (1%)	99/101 (98%)
ACAM2000 Dose 3	—	0/101 (0%)	98/101 (97%)
ACAM2000 Dose 4	—	1/51 (2%)	51/51 (100%)
Dryvax® Vaccine	—	0/49 (0%)	49/49 (100%)

Most frequent serious events

Most frequent serious events
Event	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Pregnancy Not Otherwise SpecifiedPregnancy, puerperium and perinatal conditions	1/51	1/101	0/101	1/51	0/49

Most frequent other events

Showing 10 of 17

Most frequent other events
Event	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine
Injection Site PruritusGeneral disorders	43/51	89/101	82/101	51/51	49/49
Lymph Node PainBlood and lymphatic system disorders	22/51	59/101	61/101	39/51	44/49
Injection Site ErythemaGeneral disorders	27/51	65/101	64/101	37/51	37/49
Injection Site PainGeneral disorders	22/51	59/101	58/101	35/51	35/49
Headache Not Otherwise SpecifiedNervous system disorders	30/51	51/101	49/101	24/51	28/49
FatigueGeneral disorders	23/51	41/101	55/101	29/51	28/49
MyalgiaMusculoskeletal and connective tissue disorders	21/51	40/101	47/101	26/51	27/49
MalaiseGeneral disorders	18/51	27/101	29/101	18/51	23/49
Feeling HotGeneral disorders	14/51	26/101	24/101	13/51	19/49
LymphadenopathyBlood and lymphatic system disorders	11/51	26/101	25/101	19/51	17/49

Baseline characteristics

Age, Categorical
Age, Categorical(Participants)	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine	Total
<=18 years	0	0	0	0	0	0
Between 18 and 65 years	51	101	101	51	49	353
>=65 years	0	0	0	0	0	0

Age, Continuous
Age, Continuous(Years)	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine	Total
Mean	23 ± 2.4	22 ± 3.1	22 ± 3.2	22 ± 3.0	22 ± 3.1	22 ± 3

Sex: Female, Male
Sex: Female, Male(Participants)	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine	Total
Female	18	36	34	14	13	115
Male	33	65	67	37	36	238

Region of Enrollment
Region of Enrollment(participants)	ACAM2000 Dose 1	ACAM2000 Dose 2	ACAM2000 Dose 3	ACAM2000 Dose 4	Dryvax® Vaccine	Total
United States	51	101	101	51	49	353

Study locations

4 sites

Orlando Clinical Research Center
Orlando, Florida 32806, United States
PRA International
Lenexa, Kansas 66219, United States
Bio-Kinetic Clinical Applications
Springfield, Missouri 65802, United States
Memorial Hospital of Rhode IslandDivision of Infectious Diseases
Pawtucket, Rhode Island 02860, United States

Timeline

Tracking since Sep 25, 2026

Not marked actual or estimatedDates not marked actual or estimated

The record gives a start of Jan 2003, a primary completion of Jun 2003 and a completion of Nov 2003. It does not say whether these dates are actual or estimated.

Results were first posted in Feb 2011, 7 years 8 months after primary completion.

How these figures are worked out, and which studies are left out of them.

Registered: Jan 30, 2003
First posted: Jan 31, 2003
Start: Jan 2003
Primary completionActual: Jun 2003
CompletionActual: Nov 2003
Results first posted: Feb 11, 2011
Last update: Mar 18, 2024

What these dates mean

Start.: When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.: When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.: When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.: Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.

No changes since tracking began. The registry record was last updated on Mar 18, 2024, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗

Registry details

Key details

Study ID: NCT00053495
Lead sponsor: Emergent BioSolutions
Responsible party: Sponsor
First posted: Jan 31, 2003
Start date: Jan 2003
Primary completion: Jun 2003
Completion: Nov 2003
Results posted: Feb 11, 2011
Last update: Mar 18, 2024

Study contacts

Medical Director

study director · Emergent BioSolutions

Oversight

Data monitoring committee: Yes

View the source record on ClinicalTrials.gov ↗

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