Gender Differences in Incidence and Fatality of Severe Fever with Thrombocytopenia Syndrome in China: A Comparative Study Based on National Surveillance Data

Abstract

Background: Severe fever with thrombocytopenia syndrome (SFTS) is a newly emerging infectious disease, which has a substantial burden in eastern Asia and an increasingly global concern. Differences in infectious diseases between male and female individuals are an important public health problem. Methods: We used the database containing all reported SFTS cases in mainland China, and conducted systematic evaluation of gender differences in incidence and fatality in relation to age, temporal and spatial distribution, residence location and some clinical factors. Findings: A total of 15234 SFTS cases were reported during 2010-2018. Female individuals had significantly higher average annual incidence rate (AAIR) with a RR of 1·21 (95% CI 1·17-1·25; p˂0·0001), but significantly lower case fatality rate (CFR) with an OR of 0·74 (95% CI 0·63-0.85; p<0·0001). Both AAIR and CFR were age-dependent, and significant differences were observed in age groups of 40-69 and 50-69 years, respectively (all p<0·05). There was a rising incidence and declining CFR along with epidemic years. The AAIR and CFR varied greatly from province to province. However, higher AAIR and lower CFR in females were present among epidemic years and in affected provinces. After adjusting for potential confounders, the female-to-male difference in either AAIR or CFR remained significant. Interpretation: We elucidate an age-dependent gender dimorphism, in which the SFTS incidence is higher, but the fatality is lower for females. Further epidemiological and biological investigations are required to better understand the gender-specific differences for effective interventions. Funding Statement: This study was supported by Natural Science Foundation of China (81621005). Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: As this study constituted public health surveillance rather than research in human beings, ethical approval from institutional review boards was not required. All the information regarding individual persons had been anonymized in data collection.