Persistence of Varicella Immunity in Hospital Employees Receiving Varicella Vaccine
Persistence of Varicella Immunity
Biological: Varicella vaccine
|Study Design:||Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: No masking
Primary Purpose: Health Services Research
|Official Title:||Persistence of Varicella Immunity in Hospital Employees Receiving Varicella Vaccine|
- Determine the proportion of employees who 5 years previously received varicella vaccine at the time of employment who no longer have varicella-specific antibody. [ Time Frame: Outcome measure data obtained at visit 1; assessed in the aggregate 3-6 months after completion of study. ]VZV-specific antibody measured by a sensitive gp-ELISA method at CDC
- Determine the avidity (strength with which the vaccine induced antibody binds to the varicella antigen) of varicella-specific antibody in vaccinated employees. [ Time Frame: Outcome measure data obtained at visit 1; assessed in the aggregate 3-6 months after completion of study. ]Avidity in these employees will be compared to the avidity of antibody in employees who did hot require vaccination because of natural immunity.
- Determine the varicella-specific T-cell and B-cell responses in vaccinees. [ Time Frame: At 7 and 30 days post-vaccination ]Responses will be compared to those present in employees who did not require vaccination because of natural immunity.
|Anticipated Study Start Date:||October 2017|
|Estimated Study Completion Date:||December 2018|
|Estimated Primary Completion Date:||December 2018 (Final data collection date for primary outcome measure)|
No Intervention: Sero-positive for varicella at least 5 years prior
Active Comparator: Varicella vaccine
One dose varicella vaccine (Varivax).
Biological: Varicella vaccine
Varivax 0.5ml subcutaneous injection
Other Name: Varivax
The population will be employees who were previously evaluated in the pre-employment phase by the Occupational Health Clinic (OHC) of Colorado Children's Hospital (CHC) from 2004 until 2009 and were found to be seronegative for varicella antibody at that time and were thus vaccinated per CHC protocol. Additionally, a matching number of comparator subjects who were positive for varicella antibody at the pre-employment phase will be selected from the same pool (2004-2009).
Subject participation will last up to 6 months. Subjects will be enrolled into one of two study groups:
- Group 1 consisting of 50 subjects who tested seronegative for varicella antibody and received varicella vaccine to meet employment criteria at least 5 years previously; and
- Group 2 consisting of 50 subjects who had natural varicella infection and thus tested seropositive for varicella antibody at least 5 years previously.
Group 1 subjects will receive 1 additional dose (lifetime total will be 2 or 3) of varicella vaccine (Varivax) and participate in a total of 4 study visits over a period of 6 months. Before receiving the dose of varicella vaccine at Day 1, Group 1 subjects will be given the CDC Vaccine Information Sheet for varicella vaccine. Study staff will review this with the subject to assure understanding prior to administering vaccine. Vaccination will occur after eligibility criteria have been confirmed and completion of a urine pregnancy test -with a negative result - on females of childbearing potential. Following administration of the varicella vaccine, the subject will be observed in the clinic for at least 15 minutes for safety. Blood (60 ml per sample) will be collected from all Group 1 subjects on Day 1 immediately prior to vaccination, and at Day 7(±2), Day 30(±7) and Day 180(±14) in order to measure VZV-specific antibody, antibody avidity, and cell-mediated immunity by the methods indicated above. Subjects receiving a third lifetime dose of Varivax will be asked to complete a diary for 5 days after vaccination to track anticipated and unanticipated reactions to the vaccine.
Group 2 subjects, the comparator group, will receive no vaccine and will only participate in the first visit for a blood draw. Blood (60 ml) will be collected from Group 2 participants only at Day 1. Subject information to be recorded includes age; gender; varicella vaccine history at the OHC; age vaccinated (calculate interval since vaccination); the number of doses (1 vs 2) received; and any exposure to varicella or HZ (including involvement in any CHC outbreak work-up).
Please refer to this study by its ClinicalTrials.gov identifier: NCT02026089
|Contact: Nancy E Lang, RN, BSNfirstname.lastname@example.org|
|United States, Colorado|
|Children's Hospital Colorado||Not yet recruiting|
|Aurora, Colorado, United States, 80045|
|Contact: Amanda Kennedy, RN 720-777-3535 email@example.com|
|Contact: Myron J Levin, MD 303-724-2451 firstname.lastname@example.org|
|Principal Investigator:||Myron J Levin, MD||University of Colorado School of Medicine|