Trends in dengue incidence and lethality: interrupted time series analysis, Brazil, 2001-2022

To analyze the temporal trend of dengue incidence and lethality rates and the proportions of its serotypes, in the different macro-regions of Brazil, between 2001 and 2022. In particular, the immediate and gradual effects of these indicators were verified in the periods before and after the publication of the National Guidelines for the Prevention and Control of Dengue Epidemics.

This was an interrupted time series analysis. Prais-Winsten generalized linear regression was used and the annual percentage variation was determined with a 95% confidence interval (95%CI). The data were extracted from the Notifiable Diseases Information System and the Mortality Information System.

The incidence of dengue in Brazil was stationary from 2001 to 2009, and the effects of the National Guidelines were not detectable between 2010 and 2022. The dengue fatality rate showed an increasing trend in the period 2001-2009. Between 2010 and 2022, there were gradual reductions of 30.0% in the North (95%CI -36.8; -22.5), 27.9% in the Northeast (95%CI -33.3; -22.2), 20.1% in the Southeast (95%CI -30.0; -8.8), and 17.8% in the Center-West (95%CI -22.5; -12.7). For the South, the dengue fatality rate remained stationary between 2001 and 2009 and undetectable between 2010 and 2022.

The trend in the dengue incidence rate in Brazil was stationary in the period 2001-2009. Between 2010 and 2022, it was not possible to detect immediate and gradual effects on incidence rates. The trend in dengue fatality rates in Brazil (except in the South region) was increasing between 2001 and 2009. After 2010, gradual reductions were identified.