Longitudinal Analysis of Antibody Dynamics in Severe Fever with Thrombocytopenia Syndrome Patients - High-Incidence Regions of China, 2010-2023.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Severe fever with thrombocytopenia syndrome (SFTS) is a serious tick-borne disease in East Asia with high mortality, particularly affecting the elderly. Since its discovery in 2010, inconsistencies in small-scale studies and the lack of decade-long research on antibody levels in large population samples after natural infection, along with the absence of an effective vaccine, highlight the need for large-scale, long-term data in high-incidence regions of China.

WHAT IS ADDED BY THIS REPORT?: This study of 1,410 serum samples from SFTS patients in high-incidence regions of China reveals that immunoglobulin M (IgM) levels peak at 8-14 days post-infection, declining to nearly undetectable levels by 180 days. Immunoglobulin G (IgG) and neutralizing antibodies (NAb) levels peak at 22-180 days, persisting up to 10 years. IgM levels correlate with viral load and various immune and coagulation parameters, with lower levels observed in fatal cases. During convalescence, elderly patients have lower IgG levels, whereas females exhibit higher IgG levels compared with males.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: The study's findings on long-term antibody dynamics in SFTS patients can significantly improve vaccine development, optimize therapy scheduling, inform public health policies, and enhance diagnostic tools, leading to better disease management and prevention in high-incidence areas.