The purpose of this research is to compare the ability of a new investigational smallpox vaccine called IMVAMUNE® to produce a strong immune response against smallpox disease if given as one single, higher dose compared with two lower doses given one month apart. Another purpose of the study is to see how quickly someone might be protected against smallpox. Volunteers will be vaccinia-naïve adults age 18 and older (born after 1971) divided into 2 groups. Volunteers in Group A will receive a high dose of vaccine given in 2 shots on day 0 followed by a placebo (inactive substance) shot on day 28. Group B will receive the standard dose of vaccine and placebo given in 2 shots on day 0 followed by a standard dose shot on Day 28. Study participation will include 10 planned study visits over approximately 7 months.
Despite the fact that the World Health Organization (WHO) officially declared smallpox to be eradicated, a new threat exists due to the potential use of variola virus as an agent for biological warfare and/or bio-terrorism. As a consequence, there is an urgent need for a safe and efficacious vaccine to protect the public against smallpox. To date, the majority of clinical studies with Modified Vaccinia Ankara (MVA) have studied a prime-boost vaccination regimen, with a dose of up to 1×10\^8 tissue culture infectious dose 50 (TCID50) of MVA administered on Days 0 and 28. While this vaccination regimen induces a robust immune response that is protective in a variety of animal models and is appropriate for a pre-smallpox release scenario, in the event of a confirmed release of smallpox, a more rapid vaccination regimen that provides a protective immune response would be desirable. Ideally, at least short-term protection could be obtained with a single dose of vaccine. While a single dose of MVA at 1×10\^8 TCID50, does induce an immune response in the majority of recipients, it is possible that a higher dose of MVA could provide a more rapid and/or stronger immune response relative to a single, standard 1×10\^8 TCID50 dose of MVA. The goal of this study is to examine the kinetics and magnitude of the immune response of a single high dose of MVA (5×10\^8 TCID50) relative to both a single and prime/boost regimen using the standard doses (1×10\^8 TCID50) of MVA. This study will complement a current, ongoing study, DMID Protocol 06-0012, which is examining the immune response to compressed prime/boost dosing regimens of MVA administered at (1×10\^8 TCID50). Upon the completion of these studies, clinical data will be generated which will inform policy makers about different options for post-event utilization of available smallpox vaccines. The study is designed as a randomized, non-placebo controlled, double blinded study containing two arms: Group A (N=45) will receive a single high dose of IMVAMUNE® (5x10\^8 TCID50, consisting of two 0.5 mL injections) vaccine on Day 0 and a single saline placebo dose (single 0.5 mL injection) on Day 28 to match the two dose regimen of Group B. Group B (N=45) will receive a standard two dose regimen of IMVAMUNE® (1x10\^8 TCID50) vaccine on Day 0 (consisting of 0.5 mL injection of vaccine and 0.5 mL injection of saline placebo) and Day 28 (single 0.5 mL injection of vaccine). Safety will be measured by assessment of adverse events for 28 days following the last vaccination (56 days following the initial vaccination for those subjects that fail to receive the second dose) and for serious adverse events at six months post the final vaccination, and reactogenicity to the vaccines for 15 days following each vaccination. Immunogenicity testing will include antibody testing \[enzyme linked immunosorbent assay (ELISA) and plaque reduction neutralizing antibody titers (PRNT)\] and cellular immune responses \[(INF-gamma enzyme linked immunospot (ELISPOT)\] following each vaccination and at six months post the final vaccination. In addition, ELISA responses, using MVA VR-1508 as the target antigen and PRNT using vaccinia WR (Western Reserve) as the target antigen will be explored. Participants will include 90 healthy, vaccinia-naïve adults, aged 18 and older (born after 1971). Study duration will be approximately 13 months (7 months/subject).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
91
IMVAMUNE® Vaccinia Vaccine, undiluted, delivered by subcutaneous route on Day 0 at high dose 5×10\^8 TCID50 (5×10\^8 TCID50 per 1.0 mL dose - administered as 2 x 0.5 mL.
0.5 mL injection of saline placebo administered with vaccine on Day 0 (Group B) or single saline placebo dose (single 0.5 mL injection) on Day 28 (Group A).
University of Iowa - Vaccine Research and Education Unit
Iowa City, Iowa, United States
Saint Louis University Center for Vaccine Development
St Louis, Missouri, United States
Time to Seroconversion After One Vaccination Using Bavarian Nordic's (BN) Enzyme Linked Immunosorbent Assay (ELISA) in the Intent-to-Treat (ITT) Population
Seroconversion is defined as a titer \>= 50 or as a 2-fold or greater increase in titer from baseline if pre-vaccination titer was \>= 50. Participants who did not seroconvert during the study were analyzed as right censored at the last sample collection date. Samples collected after the second vaccination were also analyzed as right censored.
Time frame: Days 0, 4, 8, 14, 21, and 28 after first vaccination
Time to Seroconversion After One Vaccination Using BN ELISA in the Per Protocol Population
Seroconversion is defined as a titer \>= 50 or as a 2-fold or greater increase in titer from baseline if pre-vaccination titer was \>= 50. Participants who did not seroconvert during the study were analyzed as right censored at the last sample collection date. Samples collected after the second vaccination were also analyzed as right censored.
Time frame: Days 0, 4, 8, 14, 21, and 28 after first vaccination
Frequency of Serious Adverse Events (SAEs) Related to Vaccination
The number of participants who experienced at least one SAE throughout the course of the study that was deemed related to the study vaccination. A SAE is defined as an AE meeting one of the following conditions: * Death during the study period (from first vaccine until end of surveillance period) * Life-threatening (defined as a participant at immediate risk of death at the time of the event) * Requires inpatient hospitalization or prolongation of existing hospitalization during the period of protocol-defined surveillance * Results in a congenital anomaly or birth defect * Results in a persistent or significant disability/incapacity * Severe adverse event associated with study product
Time frame: Day 0 after first vaccination to study completion through Day 180 after second vaccination (Day 208 after first vaccination)
Frequency of Non-Serious AEs Related to Vaccination
The number of participants who experienced at least one unsolicited non-serious AE of any severity from Day 0 to 28 days post second vaccination (56 days post first vaccination) that was deemed related to the study vaccination.
Time frame: Day 0 after first vaccination to Day 28 after second vaccination (Day 56 after first vaccination)
Frequency of Local Solicited Reactogenicity AEs for Subjective Symptoms
Local solicited reactogenicity AEs were collected daily for 15 days post each vaccination using a memory aid. Local subjective events included pain at injection site, itchiness at injection site, underarm pain, and underarm swelling and were graded on a scale of Grade 0 (None), Grade 1 (Mild), Grade 2 (Moderate), and Grade 3 (Severe).
Time frame: Day 0 through Day 15 after first vaccination; Day 0 through Day 15 after second vaccination (Day 28 through Day 43 after first vaccination)
Frequency of Local Solicited Reactogenicity AEs for Measured Symptoms
Local solicited reactogenicity AEs were collected daily for 15 days post each vaccination using a memory aid. Local measured events included erythema and induration at the vaccination site and were measured in millimeters.
Time frame: Day 0 through Day 15 after first vaccination; Day 0 through Day 15 after second vaccination (Day 28 through Day 43 after first vaccination)
Frequency of Systemic Solicited Reactogenicity AEs
Systemic solicited reactogenicity AEs were collected daily for 15 days post each vaccination using a memory aid. Systemic events included muscle aches, chills, headache, nausea, feeling tired, change in appetite, joint pain, and elevated oral temperature. Events were graded on a scale of Grade 0 (None), Grade 1 (Mild), Grade 2 (Moderate), and Grade 3 (Severe).
Time frame: Day 0 through Day 15 after first vaccination; Day 0 through Day 15 after second vaccination (Day 28 through Day 43 after first vaccination)
Peak Titer of Saint Louis University's (SLU) Plaque Reduction Neutralizing Antibody Titer (PRNT) Assay After First Vaccination in the ITT Population
The peak PRNT is defined as the largest titer among all available measurements post-first vaccination but prior to the second vaccination. Means and corresponding standard errors are calculated on the log2.5 scale.
Time frame: Days 4, 8, 14, 21, and 28 after first vaccination
Peak Titer of SLU PRNT Assay After First Vaccination in the Per Protocol Population
The peak PRNT is defined as the largest titer among all available measurements post-first vaccination but prior to the second vaccination. Means and corresponding standard errors are calculated on the log2.5 scale.
Time frame: Days 4, 8, 14, 21, and 28 after first vaccination
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