Children are particularly vulnerable to respiratory virus infections, especially influenza. Vitamin A \& D deficiencies are associated with vulnerability to infectious diseases of the respiratory tract. The central hypothesis of this protocol is that vitamin supplements will enhance antibody responses toward the flu vaccine in children. Children, 2-8 years old, will be randomized to receive influenza virus vaccine with a vitamin A+D supplement or influenza virus vaccine with placebo. Children will be tested for vitamin levels and immune responses before and after influenza virus vaccinations to determine if vitamin supplementation improves the influenza virus vaccine-induced immune response. PRIMARY OBJECTIVE: * To assess the vaccine-induced and total antibody (including IgG and IgA) response after influenza virus vaccine administration and IgA/IgG plus IgA/IgM ratios at 28 and 56 days in sera SECONDARY OBJECTIVE: * To assess the neutralizing response toward influenza virus vaccine in the sera.
Participants will be randomized to receive either an influenza virus vaccine plus Vitamins A \& D or an influenza virus vaccine plus placebo. They will be stratified based on retinol binding protein (RBP) levels at screening, using a cut-off indicative of Vitamin A insufficiency (≤22,000 ng/ml). Co-enrolled sibling participants will be first stratified by RBP levels, then siblings within the same stratum will be equally assigned to different arms to provide greater assurance of balanced treatment assignment. Children will be tested for vitamin levels and immune responses before and after influenza virus vaccinations to determine if vitamin supplementation improves the influenza virus vaccine-induced antibody immune response. All participants will receive two doses of an influenza virus vaccination administered at least 28 days apart. Vitamin levels and antibody responses toward the vaccine will be measured on day 0 (baseline levels obtained where day 0 equals the first influenza virus vaccination administration), day 28, and day 56. Placebo or Vitamins A + D (at the levels of 20,000 IU and 2,000 IU, respectively) will be administered orally on the days of vaccination. Blood serum samples will be collected from participants on Day 0, prior to receiving influenza virus vaccine on Day 28, and during their Day 56 follow-up visit. Parents will be asked to fill out diary cards to indicate food intake for children during the study period along with an optional food frequency questionnaire given on day 56. Specific measurements on days 28, and 56 will include analyses of vaccine-specific and total IgA, IgG, and IgA/IgG plus IgA/IgM ratios in sera. Functional activities of antibodies toward influenza vaccine will also be measured.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
87
Children will have the first influenza virus vaccine dose (dose 1) administered on day 0 of the trial, and the second dose (dose 2) administered 28 days later.
The chewable gummy contains either Vitamin A (20,000 International Units) and Vitamin D3 (2,000 International Units), which should be fully chewed under supervision of study staff with documentation in the participant's research record and eMAR (electronic medical administration record). The chewable gummy should be administered prior to receiving influenza virus vaccination.
The chewable gummy matched placebo will be formulated with gelatin base and tangerine oil and match the Vitamin A and D in shape, taste, texture, and appearance. Gummies should be fully chewed under supervision of study staff with documentation in the participant's research record and eMAR (electronic medical administration record). The chewable gummy should be administered prior to receiving influenza virus vaccination.
St. Jude Children's Research Hospital
Memphis, Tennessee, United States
Percentage of Participants With Positive Responses in Virus-specific Antibody in Sera
The percentage of 2X increases or conversion from undetectable to detectable response in virus-specific antibody toward any vaccine component after 2 immunizations in intervention and control groups will be reported.
Time frame: Day 56 after vaccination
Isotype Ratios on Day 56
Isotype ratios will be summarized with descriptive statistics.
Time frame: Day 56 after vaccination
Percentage of Participants With Seroconversion at Day 56 After Vaccination, Overall
Secondary analyses will examine sero-conversion based on antibody functions (HAI or neutralization) defined as antibody titers of \<1:40 converting to ≥1:40, or a four-fold increase in titer for participants with a starting titer of ≥1:40. Sero-conversion rate (expressed as percentage) will be estimated with 95% confidence interval. The rate difference will be described with point estimate and 95% confidence interval.
Time frame: Day 56 after vaccination
Percentage of Participants With Seroconversion at Day 56 After Vaccination, by Vitamin A Levels at Screening
Secondary analyses will examine sero-conversion based on antibody functions (HAI or neutralization) defined as antibody titers of \<1:40 converting to ≥1:40, or a four-fold increase in titer for participants with a starting titer of ≥1:40. Sero-conversion rate (expressed as percentage) will be estimated with 95% confidence interval for participants sufficient and insufficient in vitamin A at screening.
Time frame: Day 56 after vaccination
HAI Titers at Day 56 After Vaccination, Overall
Time frame: Day 56 after vaccination
HAI Titers at Day 56 After Vaccination, by Vitamin A Levels at Screening
Time frame: Day 56 after vaccination
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