Excess deaths associated with the 2014 chikungunya epidemic in Jamaica

Although traditionally chikungunya virus is considered non-fatal, recent studies suggest that there may be in fact underreporting of deaths in some situations. A major chikungunya epidemic hit Jamaica in 2014 but no chikungunya-associated deaths were reported. We assessed the excess of all-cause deaths during this epidemic. Excess deaths were estimated by difference between observed and expected mortality based on the average age-specific mortality rate of 2012-2013, using the 99% confidence interval. There was an excess of 2,499 deaths during the epidemic (91.9/100,000 population), and a strong positive correlation between the monthly incidence of chikungunya and the excess of deaths (Rho = 0.939, p < 0.005). No significant concomitant epidemiological or climatic phenomenon occurred. Chikungunya is a major contributor to morbidity during epidemics and may be an unrecognized cause of death. Thus, it is urgent to review clinical protocols and improve the investigations of specific-cause deaths during chikungunya epidemics. Excess deaths could be a strategic tool for epidemiological surveillance.