Global trends and prevalence of scabies: a spatiotemporal analysis using Global Burden of Disease 2021 data

BackgroundScabies is a neglected disease believed to be more prevalent in resource-poor nations. Data describing global temporal trends of scabies incidence and prevalence and risk factors is limited. MethodsThis paper uses joinpoint regression and spatial analysis to estimate age-standardized rates (ASR) of scabies incidence and prevalence and temporal trends in 204 countries and regions from 1990 to 2021. Local indicators of spatial association were used to determine contiguous areas of high prevalence. The association of socio-demographic and economic factors with scabies was determined using locally weighted scatterplot smoothing and log-normal regression models. FindingsGlobal prevalence of scabies in 2021 was 2.71% (95% confidence interval [CI]: 2.41 to 3.04%). Age-standardized rates of scabies have marginally declined globally from 1990 to 2021 with an Average Annual Percentage Change (AAPC) of -0.10 (95% CI -0.05 to -0.14) for incidence and -0.09 (95% CI -0.05 to -0.14) for prevalence. Spatial clustering of high scabies prevalence was present in tropical Latin America, Southeast Asia, and the Pacific Islands. Rates have shown an increasing trend in high-income regions such as Australasia and parts of Europe. Scabies showed a declining trend from middle to high socio-demographic index (SDI) regions. There is a significant positive association between warmer latitudes and increasing urbanization and scabies prevalence. InterpretationScabies prevalence remains high in many regions. Control programmes should be prioritized to accelerate progress to reduce prevalence of this important neglected disease.