Excess Mortality Related to Chikungunya Epidemics in the Context of Co-circulation of Other Arboviruses in Brazil

The objective of this study was to assess the mortality associated with chikungunya epidemics in Brazil by comparing the mortality of pre-chikungunya with mortality during chikungunya epidemics2,3. Methods We studied the 3 Brazilian states with higher chikungunya incidence rates (IR), Pernambuco (9,410,772 inhabitants), Rio Grande do Norte (3,474,998 inhabitants), and Bahia (15,498,733 inhabitants)5. Bahia is the largest and most populated state, with a heterogeneous incidence of chikungunya, and therefore we analyzed separately each one of 9 administrative regions of Bahia. We retrospectively analyzed anonymous, publicly available data from the Brazilian Ministry of Health. To evaluate the possible effect of chikungunya on all-cause mortality, we compared the number of deaths expected for the current estimated population with that observed during the epidemic, during 2015 and 2016. Given the lack of previous data of the CHIKV circulation in the studied regions, we arbitrarily considered as epidemic period onset on first of at least two consecutive months with incidence rates higher than 50 cases per 100 thousand population; and for the end of epidemic period we defined as incidence rate lower than 50 per 100 thousand for two consecutive months for all studied regions. We plot the incidence rate of dengue during 2015 and 2016 in all studied regions for comparing. The expected mortality rates were calculated based on the mean monthly Age Standardized Mortality Rate (ASMR,...
Source: PLOS Currents Outbreaks - Category: Epidemiology Authors: Source Type: research