Efficacy of severe fever with thrombocytopenia syndrome vaccines in animal models: a systematic review and meta-analysis

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne zoonosis that threatens both animal and human health across East Asia, yet no licensed vaccine is currently available. We therefore conducted a PRISMA-guided systematic review and meta-analysis of preclinical murine and ferret studies to evaluate severe fever with thrombocytopenia syndrome virus vaccine efficacy. Seven electronic databases were searched for studies published between 2009 and 2025. Random-effects meta-analyses evaluated mortality, viremia, and post-challenge weight loss. Quantitative viral burden was further evaluated using standardized mean differences for mean and peak viremia, whereas body-weight trajectories were assessed using generalized linear mixed models. Twenty-three studies met the inclusion criteria. Vaccination markedly reduced mortality (RR = 0.10, 95% CI 0.05–0.21), post-challenge weight loss (RR = 0.21, 95% CI 0.12–0.37), and detectable viremia (RR = 0.45, 95% CI 0.27–0.73), although the effect estimate was attenuated in the trim-and-fill sensitivity analysis (RR = 0.74, 95% CI: 0.36–1.51). Furthermore, significantly suppressing both mean and peak viremia under homologous and heterologous challenge conditions. Longitudinal analyses further demonstrated improved preservation of body weight, particularly following mRNA and vector vaccination. These findings provide the strongest quantitative evidence supporting the development of broadly protective SFTSV vaccines for both human and veterinary use within a One Health framework.