# Human‐to‐Human Transmission of Severe Fever With Thrombocytopenia Syndrome Resulting in Fatal Cases: A Case Series

## TL;DR

This paper reports a deadly case series of human-to-human transmission of SFTS in China, emphasizing the risks to the elderly and the need for better early diagnosis and prevention.

## Contribution

The study provides the first documented cluster of fatal human-to-human SFTS transmission and highlights critical gaps in clinical management.

## Key findings

- Six SFTS cases, including five secondary infections, were traced to an index patient in China with an 83% mortality rate.
- Secondary infections occurred in elderly individuals due to exposure to body fluids, not tick bites.
- The outbreak revealed significant delays in early diagnosis and clinical management of SFTS.

## Abstract

Severe fever with thrombocytopenia syndrome (SFTS), primarily a tick‐borne disease, can also cause fatal human‐to‐human transmission. This report analyzes a cluster of six SFTS cases identified in China in 2022, involving one index patient and five secondary infections, with an overall mortality of 83%. All secondary cases occurred in elderly individuals (aged 66–85 years) following unprotected exposure to the index patient’s body fluids during bedside care or traditional postmortem rituals, without documented tick bites. The high fatality rate underscores the potential severity of secondary transmission, particularly among elderly adults. More critically, this outbreak exposes systemic delays in early diagnosis even within an endemic area, highlighting fundamental gaps in the clinical management of undifferentiated fever. Effective prevention, therefore, relies on establishing a clinical system for early detection, rapid diagnosis, and prompt isolation while implementing culturally adapted community interventions to reliably interrupt transmission.