176. Remdesivir for Post-Exposure Prophylaxis of Marburg Virus Disease: A Cohort Study Assessing Safety, Clinical, and Immunologic Outcomes

Abstract Background Marburg Virus Disease (MVD) outbreaks have mortality rates up to 90% and disproportionately affect healthcare workers (HCWs). Although no treatments are approved, remdesivir, an antiviral drug that inhibits RNA-dependent RNA polymerase, was shown to protect against MVD in animal models. This study aims to evaluate the safety, clinical, and laboratory outcomes among HCWs who received a 3-day course of remdesivir following suspected MVD exposure during the 2024 outbreak in Rwanda.Table 1Characteristics of HCWs exposed to MVD during the 2024 Rwanda outbreakTable 2Description of MVD exposure and clinical outcomes and NPS antibody results Methods Between September 27 and October 30, 2024, intravenous remdesivir (200 mg on Day 1, 100 mg on Days 2-3) was offered as post-exposure prophylaxis (PEP) to HCW who had worked at least one shift in MVD-affected units.Liver function tests (LFTs) and symptom assessments were performed pre- and post-remdesivir infusion. In March 2025, eligible HCWs were surveyed about post-treatment symptoms and provided blood samples for Marburg virus-specific antibody testing.CT values and incubation periods from MVD-positive individuals without PEP (Rwanda Biomedical Center) were compared to MVD-positive PEP participants in this study. Analyses used STATA v28.Table 3.Remdesivir Possible side effects, MVD severity and antibody testing among participants who received remdesivir only (N=194)Graph 1.Box plot of CT values and incubation Period among Remdesivir use status Results By July 14, 2025, 380 HCWs were enrolled: 194 (51%) received PEP and 186 (49%) declined. Participant characteristics are shown in Table 1. Overall, 261 (68.7%) reported MVD testing; 20 (5.3%) were hospitalized with MVD-like symptoms, and 11 (3.2%) tested positive. MVD exposure risks are presented in Table 2.15 HCWs (4%) developed MVD-specific antibodies. Table 3 summarizes self-reported complications and MVD severity. A significant difference in incubation period was observed between PEP recipients (median: 11 vs. 8 days; P = 0.0014).Seroprevalence was higher in the PEP group (5.6%) than in the non-PEP group (2.2%). CT values were similar (median: 26.29 vs. 25.38; P = 0.41), with less variation in the PEP group (Graph 1). LFTs showed no notable changes pre- and post-remdesivir. Conclusion Remdesivir appears safe as post-exposure prophylaxis (PEP) for HCWs during MVD outbreaks.findings suggest that remdesivir may lead to a clinically and statistically significant extension of the incubation period, as well as a modest reduction in viral load at the time of diagnosis. However, controlled clinical trials are needed to confirm its preventive efficacy. Disclosures All Authors: No reported disclosures