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CompletedNCT00050505Updated Dec 5, 2014

Expanded Dryvax Dilution Study in Previously Vaccinated Adults

A Phase 2 interventional study of Live vaccinia virus vaccine and Live vaccinia virus vaccine in Smallpox, sponsored by National Institute of Allergy and Infectious Diseases (NIAID). Completed at 7 sites in United States. Open to participants aged 32 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2014-12-05.

Sponsored by National Institute of Allergy and Infectious Diseases (NIAID) · Phase 2, Interventional, and Prevention

Phase
Phase 2
Study type
Interventional
Enrollment
927
Allocation
Randomized
Ages
32 Years to 70 Years
Sex
All
01

Study summary

The purpose of this study is to determine the safety and effect of diluting smallpox vaccine, making a larger number of doses in case smallpox is released into the environment. A total of up to 927 healthy adults between the ages of 32 and 70 years who were already vaccinated against smallpox (but not since 1989) will volunteer for this study for up to 34 weeks and receive different strengths of vaccine. Some subjects may participate for longer if they choose to be revaccinated because the first vaccination does not take. The vaccine will be given by making small cuts in the skin and putting the vaccine into these cuts. After the screening visit, volunteers will be followed through study visits and follow up phone calls. Blood will be collected during some study visits to look at the immune system (body system that fights infection) response.

Read the detailed description

The purposes of this multi-center, double blind randomized dose response study are: to evaluate the safety of undiluted Dryvax and Dryvax diluted at 1:5 and 1:10 in adults between the ages of 32 and 70 years who were previously vaccinated but not since 1989 and to define, with very high precision (+/-3%), the proportion of individuals who respond with a "take" 6 to 11 days after vaccination with undiluted Dryvax vaccine and Dryvax diluted at 1:5. A "take" is defined as the formation of a lesion at the site of vaccination that is consistent with the description of a successful vaccination described in the IB Secondary study objectives include defining with good precision (+/- 10%), the proportion of individuals who respond with a "take" 6 to 11 days after vaccination with a 1:10 dilution of Dryvax vaccine and exploring correlations between "takes"/ no-"take" and immune responses in all vaccine groups (antibody responses in all volunteers; and assays of cell-mediated immunity in a convenience sample consisting of 15 volunteers enrolled at each site (total N = 105) randomly distributed across the vaccine groups). Immunogenicity assays will include neutralizing antibody to vaccinia, vaccinia binding antibody, ELISPOT for gamma interferon [Assays of cell-mediated immunity will be performed only on a convenience sample consisting of 15 volunteers enrolled at each site (total N = 105)] and intracellular cytokine production. Primary safety endpoints include safety data regarding the three doses of vaccine in previously vaccinated subjects as assessed by adverse events reported by the subjects and/or investigators and changes observed during the scheduled clinic visits. Specific attention will be paid to the following: local reactogenicity at the site of injection: pain, tenderness, erythema, induration, regional lymphadenopathy, limitation of limb movement; systemic symptoms: fever, myalgia, fatigue, and headache; anaphylaxis, and hypersensitivity reactions; other reactions: dermatologic, neurologic, gastrointestinal (nausea/vomiting, diarrhea). The primary efficacy endpoint for this trial will be the proportion of vaccinees demonstrating a "take" 6 to 11 days after the first vaccination at each of the dose levels (undiluted and 1:5 and 1:10). Secondary endpoints are: immune responses as assessed by vaccinia neutralizing antibody measured on all subjects and binding antibody to vaccinia on all subjects and the size of the lesions observed in all subjects compared across the dilution groups. Tertiary endpoints of 15 volunteers at each site randomly distributed across the vaccine groups are cellular immune responses as assessed by: ELISPOT for gamma interferon in response to vaccinia antigens and intracellular cytokine production.

02

Conditions studied

  • Smallpox

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Keywords

  • smallpox, Dryvax, vaccine, dilution
03

In context

Smallpox

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

This study's enrollment of 927 is above the median of 150 across 61 interventional studies indexed under Smallpox.

Browse Smallpox studies →

Lead sponsor

National Institute of Allergy and Infectious Diseases (NIAID) is the lead sponsor of 2,446 studies on the registry; 179 are open to participants now.

Of its 405 completed or terminated interventional studies of FDA-regulated products, 302 (75%) have results posted.

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

04

Who can participate

Ages eligible
32 Years to 70 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

  1. Age 32 to 70 years.
  2. Typical vaccinia scar or validated documentation (e.g., military record, international travel certificate) of a smallpox vaccination, but not since 1989.
  3. Willing to sign .
  4. Availability for follow-up for the planned duration of the study (at least 26 weeks after vaccination).
  5. Acceptable medical history by screening evaluation and brief clinical assessment.
  6. Negative urine or serum pregnancy test for women of .
  7. If the subject is female and of childbearing potential, she must use an acceptable and not become pregnant within 56 days post vaccination. (Acceptable contraception includes implants, injectables, combined oral contraceptives, effective intrauterine devices (IUDs), sexual abstinence, or a vasectomized partner).
  8. Negative ELISA for or indeterminant Western blot or other assay confirming that the serostatus does not reflect HIV infection
  9. \< 1.5 times institutional .
  10. Negative surface antigen and negative antibody to virus.
  11. Negative urine glucose by dipstick.
  12. Adequate renal function defined as a serum creatinine less than or equal to 1.5 mg/dL; urine protein \< 100 mg/dL or trace or negative proteinuria by dipstick; and a calculated > 55 mL/min based on the formulas in the manual of procedures.
  13. Hematocrit > 34% for females, > 38% for males; > 150,000/mm3; and WBC > 2,500/mm3 and \< 11,000/mm3.

Exclusion criteria

Exclusion Criteria:

  1. Smallpox vaccination in 1990 or more recently.
  2. History of immunodeficiency.
  3. Known or suspected impairment of immunologic function including, but not limited to, liver disease; diabetes mellitus; moderate to severe kidney impairment.
  4. , other than squamous cell or basal cell skin cancer.
  5. Active disease.
  6. Use of medication.
  7. Medical or psychiatric condition or occupational responsibilities that preclude subject compliance with the protocol.
  8. History of "illegal" injection drug use.
  9. Inactivated vaccine 14 days prior to vaccination
  10. within 60 days of study.
  11. Use of agents within 30 days prior to study.
  12. Receipt of blood products or immunoglobulin in the past 6 months.
  13. Acute febrile illness on the day of vaccination.
  14. Pregnant or lactating women.
  15. Eczema of any degree or history of eczema.
  16. History of chronic exfoliative skin disorders/conditions.
  17. Any acute skin disorders of large magnitude, e.g., laceration requiring sutures, burn greater than 2 x 2 cm.
  18. Household contacts/sexual contacts with, or frequent and/or prolonged exposure to, any of the following:

    • Pregnant women
    • Children \< 12 months of age
    • People with or history of eczema
    • People with chronic exfoliative skin disorders/conditions or any acute skin disorders of large magnitude. e.g., laceration requiring sutures, burn greater than 2 x 2 cm
    • People with immunodeficiency disease or use of immunosuppressive medications
  19. Any condition that, in the opinion of the investigator, might interfere with study objectives.
  20. Known allergies to any component of the vaccine (e.g., polymyxin B sulfate, dihyrostreptomycin sulfate, chlortetracycline hydrochloride, neomycin sulfate).
  21. Known allergies to any known component of the diluent (i.e., glycerin and phenol).
  22. Known allergies to any known component of VIG, i.e., thimerosal or previous allergic reaction to immunoglobulins.
  23. Known allergies to cidofovir or probenecid.
Terms in these criteria, in plain language(16)

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.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

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.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

Creatinine clearance (CrCl)

How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

Autoimmune disease

A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.

Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.

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.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

05

Study design

Phase
Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Double (Participant, Investigator)
Enrollment
927 participants (actual)

Study arms

  • Experimental
    Cohort C

    N=100 to 110 subjects receives 1:10 diluted dose of Dryvax vaccine on Day 0 and 1:5 revaccination dose on Day 56

    Biological: Live vaccinia virus vaccine

  • Experimental
    Cohort B

    N=571 to 581 subjects receives 1:5 diluted dose of Dryvax vaccine on Day 0 and 1:5 revaccination dose on Day 56

    Biological: Live vaccinia virus vaccine

  • Experimental
    Cohort A

    N=226 to 236 subjects receives undiluted dose Dryvax vaccine on Day 0 and 1:5 revaccination dose on Day 56

    Biological: Live vaccinia virus vaccine

Interventions

  • BiologicalLive vaccinia virus vaccine

    Dryvax undiluted. Cohort A receives undiluted dose of Dryvax vaccine

  • BiologicalLive vaccinia virus vaccine

    Dryvax with diluent (50% glycerin and 0.25% phenol in sterile water). Cohort A-C receives diluted dose of Dryvax vaccine.

06

What researchers measure

Primary outcomes

  1. Proportion of vaccinees demonstrating a "take" 6 to 11 days after the first vaccination at each of the dose levels (undiluted and 1:5 and 1:10).

    Time frame: 6 to 11 days after the first vaccination at each of the dose levels (undiluted and 1:5 and 1:10).

07

Study locations

7 sites
  • Kaiser Permanente Vaccine Study Center
    Oakland, California 94612, United States
  • Stanford University
    Stanford, California 94305-5208, United States
  • UCLA Center For Vaccine Research
    Torrance, California 90502, United States
  • University of Maryland Baltimore
    Baltimore, Maryland 21201, United States
  • Saint Louis University
    St. Louis, Missouri 63110, United States
  • University of Rochester
    Rochester, New York 14642, United States
  • Duke Health Center
    Durham, North Carolina 27704, United States
08

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 5, 2014, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT00050505
First posted
Dec 11, 2002
Start date
Oct 2002
Completion
Dec 2003
Last update
Dec 5, 2014
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Jul 2009. You cannot join it, but the record below documents what was studied.

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