Report of a SPEAC webinar 22 september 2023: Sensorineural hearing loss, lassa virus disease and vaccines.

Lassa virus (LASV) belongs to the Arenavirus family. LASV is endemic in several West Africa countries and causes viral hemorrhagic fevers. The Nigeria CDC has reported that an outbreak in 2024 in 28 states has resulted in 7767 suspected cases of Lassa fever, 971 confirmed cases and 166 confirmed deaths up to 11 August. Since infection with LASV can result in sensorineural hearing loss (SNHL) in up to 30% of patients, there are questions about whether triggering the immune response by immunization with LASV vaccines could potentially cause SNHL, although this has not been shown in clinical trials to date. To address this issue, the Coalition for Epidemic Preparedness Innovations (CEPI) and the Brighton Collaboration (BC) Safety Platform for Emergency vACcines (SPEAC) convened a three-hour webinar on 22 September 2023 to review what is known from both animal studies and human clinical trials and how hearing assessments in future clinical trials can help to assess the risk. This report summarizes the evidence presented and provides considerations for hearing assessment in expanded human trials of LASV vaccine candidates in children and adults.