Measuring the Prevalence of Infant Measles in Mali
Dr. Wilbur Chen
School of Medicine
Measles is a highly contagious yet vaccine-preventable disease for which the largest burden is in the WHO African Region (AFR). Measles elimination has been hampered by low measles vaccination rates and more recently sub-Saharan Africa has experienced a resurgence of measles. We recently (2022) performed a Phase 3 meningococcal vaccine study in infants in Bamako, Mali (DMID 20-0024) wherein we observed that 100% of our study infants (age 9-months) demonstrated anti-measles antibody >200 mIU/mL (seropositive response for measles) after their first dose of
measles-containing vaccine (MCV1). This is a surprisingly high seropositive response rate for infants subsequent to MCV1. [Our Hypothesis] Nearly all infants in Mali experienced natural measles infection prior to 9-months of age. Furthermore, this could indicate a failure of existing measles control programs--a situation that requires immediate attention.
We have teamed with the CDC's Measles Virus Lab, developing a high-throughput, low-volume, multi-plex method for the measurement of measles and rubella antibody (Luminex-based Multiplex Bead Assay, MBA). The MBA has been validated and calibrated to WHO International Standards. The CDC is eager to assess the measles baseline antibody levels in infant samples (future-use authorized frozen aliquots) from our study (DMID 20-0024). The plan is to assess measles antibody levels in up to N=1122 pairs of serum samples (Day 1 baseline and Day 29 post-vaccination serum sample pairs). The CVD and the CDC Measles Virus Lab executed a UBMTA (Uniform Biological Materials Transfer Agreement) November 26, 2024; internal CDC ethical approval was received June 7, 2024. Meanwhile, we have had no funding mechanism to cover the cost of the international shipment of specimens from Bamako to Atlanta and for the analysis and correlation of the immunogenicity assessments. Therefore, this PGIF funding opportunity could fully support this important public health project.