Understanding antibody-based SARS-CoV-2 immunity is critical for overcoming the COVID-19 pandemic and informing vaccination strategies. We evaluated SARS-CoV-2 antibody dynamics over 10 months in 963 individuals who predominantly experienced mild COVID-19. Investigating 2,146 samples, we initially detected SARS-CoV-2 antibodies in 94.4% individuals, with 82% and 79% exhibiting serum and IgG neutralization, respectively. Approximately 3% of individuals demonstrated exceptional SARS-CoV-2-neutralization, with these ‘elite neutralizers’ also possessing SARS-CoV-1 cross-neutralizing IgG. Multivariate statistical modeling revealed age, symptomatic infection, disease severity and gender as key factors predicting SARS-CoV-2 neutralizing activity. A loss of reactivity to the virus spike protein was observed in 13% individuals 10 months after infection. Neutralizing activity had half-lives of 14.7 weeks in serum versus 31.4 weeks in purified IgG, indicating a stable long-term IgG antibody response. Our results demonstrate a broad spectrum in the initial SARS-CoV-2-neutralizing antibody response, with sustained antibodies in most individuals for 10 months after mild COVID-19.

Objectives: Lassa fever (LF) causes annual outbreaks in endemic regions with high mortality of symptomatic patients. Ribavirin is recommended as standard treatment for LF in national and international guidelines but the evidence base for this recommendation has been questioned recently. Methods: We conducted a systematic review and included 6 studies providing efficacy data of ribavirin treatment for LF (PROSPERO protocol CRD42018103994). Results: Besides retrospective case series, the evidence mostly relies on a single prospective clinical trial with critical risk of bias. In this trial, LF associated mortality is reduced for patients with elevated aspartate aminotransferase (AST) when treated with ribavirin (OR 0.41, 95% CI 0.23-0.73), while mortality is higher for patients without elevated AST (OR 2.37, 95% CI 1.07-5.25). Conclusions: Based on the available data, current treatment guidelines may therefore put patients with mild LF at increased risk of death. The role of ribavirin in the treatment of LF requires urgent reassessment.