A scoping review on Lassa fever in Nigeria and the implication for disabling hearing loss

Background: Lassa fever (LF) affects thousands of Nigerians yearly, yet its long-term complications, particularly sensorineural hearing loss (SNHL), remain underrecognized. This scoping review collated current knowledge, socioeconomic consequences, and preventive strategies of LF-induced hearing loss in Nigeria. Methods: We followed the Arksey and O'Malley framework and reported per PRISMAScR guidelines. PubMed, Google Scholar, Scopus, African Journals Online, NCDC reports, and WHO fact sheets were searched for records (January 2000–June 2025) using terms including "Lassa fever" and "hearing loss." Eligible sources included English peerreviewed studies, surveillance reports, and policy/economic analyses. Two reviewers independently screened and extracted data, resolving disagreements by consensus. Thirty-six records were included. Formal risk of bias assessment was not conducted, consistent with scoping review methodology; methodological features were appraised narratively where relevant. Results: Seven Nigerian and Sierra Leonean studies reported LF-associated hearing loss across 250 survivors and acute cases. Prevalence of self-reported and audiometrically confirmed SNHL ranged from 12.5–30.0% and 13.5–29.0%, respectively. Hearing loss was independent of acute-disease severity and persisted in 64.0% of cases. NCDC recorded 1,309 confirmed cases and 214 deaths in 2024, with spread across 34 of Nigeria's 36 states between 2018 and 2023. Global hearing-aid production meets only 3.0% of demand in low- and middle-income countries. Conclusion: LF-induced SNHL is common but underrecognized. Scarce audiometric follow-up and limited long-term economic data remain critical gaps. Routine audiological screening within survivor care and investment in affordable hearing rehabilitation are urgent priorities.