The Use of an Herbal Formula by Hospital Care Workers During the Severe Acute Respiratory Syndrome Epidemic in Hong Kong to Prevent Severe Acute Respiratory Syndrome Transmission, Relieve Influenza-Related Symptoms, and Improve Quality of Life: A Prospective Cohort Study

Objectives: To investigate the efficacy of an herbal formula in the prevention of severe acute respiratory syndrome (SARS) transmission among health care workers. The secondary objectives are to investigate quality of life (QOL) and symptomology changes among supplement users, and to evaluate the safety of this formula. Design: Controlled clinical trial. Settings: Hong Kong during epidemic of SARS. Subjects: Two cohorts of health care workers from 11 hospitals in Hong Kong, 1 using an herbal supplement for a 2-week period (n = 1063) and a control cohort comprising all other health care workers who did not receive the supplement (n = 36,111) were compared prospectively. Interventions: Taking an herbal supplement for a 2-week period. Outcome measures: SARS attack rates and changes in quality of life and influenza-like symptoms were also examined at three timepoints among herbal supplement users. Results: None of the health care workers who used the supplement subsequently contracted SARS compared to 0.4% of...