Unraveling Natural and Vaccine-Elicited Immunity to Lassa Fever (UNVEIL)

We will use the minimum number of patients required to achieve statistical significance for the biomarker/correlate of interest, which may include up to 100 patients across all clinical sites (3 sites in Nigeria plus one site in Sierra Leone). While we intend to collect samples from multiple sites in Nigeria and Sierra Leone, sample collection will be halted after we accumulate enough samples to achieve statistical significance regardless of location. Lassa patients will be serially sampled at the following timepoints: blood (plasma) samples collected every other day during the acute phase (10-14 days) plus 1 month, 6 months, and 12 months; PBMCs will be collected at 0 days, 10 days, 28 days, 6 months, and 12 months. Hearing tests will be performed at 4 days, 2 weeks, 6 months, and 12 months. Blood tests for electrolytes, complete blood cell counts, and protein biomarkers will also be conducted during the acute phase and convalescence.