The global burden of chikungunya virus and the potential benefit of vaccines

The first chikungunya virus (CHIKV) vaccine has now been licensed, however, its potential to reduce disease burden remains unknown due to a poor knowledge of the underlying global burden. We use data from seroprevalence studies, observed cases and mosquito distributions to quantify the underlying burden in 190 countries and territories, and explore the potential impact of the vaccine. We estimate that 104 countries have experienced transmission, covering 2.8 billion individuals and that in epidemic settings, the mean duration between outbreaks is 6.2 years, with 8.4% of the susceptible population infected per outbreak. Globally there are 33.7 million annual infections, driven by countries in Southeast Asia, Africa and the Americas. Assuming a vaccine efficacy against disease of 70% a protection against infection of 40%, vaccinating 50% of individuals over 12 years old in places and times where the virus circulates would avert 3,718 infections, 2.8 deaths and 158 DALYs per 100,000 doses used. These findings highlight the global burden and the significant potential of the vaccine.