Investigating immune amnesia after measles virus infection in two West African countries: A study protocol

"Investigation of Immune Amnesia Following Measles Infection in Select African Regions" (ClinicalTrials.gov Identifier: NCT06153979) is a prospective, observational, longitudinal study being conducted in two West African countries, Guinea, and Mali. The overall goal is to investigate the impact of measles virus (MeV) infection on pre-existing immunity, vaccine response, and susceptibility to subsequent illness. A total of 256 children aged 1 to 15 years are being enrolled into one of two study arms: those with acute MeV infection (cases) and without (controls). Acute MeV is confirmed by RT-PCR testing on upper respiratory specimens or IgM detection on blood samples at screening. Blood samples are collected at multiple time points at screening (Day 0), at an optional visit to repeat IgM serology for inconclusive or negative Day 0 results (Day 7-10), and during follow-up visits on Day 14, Week 13, and Week 52. These blood samples will be tested to evaluate both humoral and cellular immune responses to endemic pathogens to measure variations in antibody diversity and antibody secreting cells (ASCs). To explore how recent MeV infection may affect the childs ability to respond to a controlled immune stimulus, all participants will receive rabies vaccine pre-exposure prophylaxis (PrEP) using Verorab inactivated rabies vaccine. Three doses of 0.5 ml of VERORAB vaccine are administered on Days 0, 7, and 28. Biological samples will be collected after vaccination to assess if the rabies vaccine response differs: 1) between cases and controls, and 2) based on the timing of the rabies vaccination after acute measles infection. In addition, the study team will collect information on healthcare encounters during the year-long follow-up will be collected to determine if there is a difference in the number of encounters by study group. The findings of this study will further the understanding of the MeV immune amnesia phenotype.