Project Details
E.W. "Al" Thrasher
Status: Funded - Open
Immunological evaluation of early measles vaccination in Vietnam
Summary
BACKGROUND: Measles represents a growing global public health concern, with over 10 million estimated cases in 2023 and current outbreaks in all regions of the world. Most infants in low- and middle-income countries no longer have protective antibody levels by four months of age, leaving them vulnerable to infection before their first routine measles vaccine dose (at nine months of age). Infants are at high risk of severe illness and death, so protecting this group is of particular importance. GAP: To date, no studies have assessed the immediate total (combined humoral and cellular) immune response to a 4-month dose of measles containing vaccine (MCV), which provides a measure of the expected protection against measles. Two recent trials evaluated MCV given at 6 months but had conflicting results. There are also few data on the effect of early MCV on responses to the routine 9-month dose. HYPOTHESIS: We hypothesise that there is no difference in 1) the antibody seroconversion rate and the total immune response rate, between infants who received early MCV administered at 4 months or 6 months, and 2) the antibody seroconversion rate and the total immune response rate following a 9-month dose, between infants who did or did not receive an early MCV dose. METHODS: This is a single-blind open-label randomized controlled trial. Healthy infants will be randomized to one of three groups to receive: early MCV at 4 months (Arm 1), early MCV at 6 months (Arm 2), or no early MCV (Arm 3). All infants will receive routine MCV at 9 months and will be followed up to 10 months of age. Blood samples will be collected pre- and 28 days post-MCV doses for measles IgG antibody levels (all participants) and measles-specific T cell responses (among those who fail to seroconvert). RESULTS: Pending. IMPACT: By providing detailed immunological evaluation of early MCV at 4 and 6 months of age, we will generate the evidence needed to support global measles policy.