Highlights•CHIKV adaptation to new urban vector, A. albopictus, can facilitate
epidemics.•Epistatic mutations can constrain adaptation of some CHIKV lineages to A.
albopictus.•CHIKV strains circulating in the Americas are less likely to adapt to A.
albopictus.•The risk for establishment of an enzootic CHIKV cycle in the neotropics is
uncertain.•Growing herd immunity will likely modulate the CHIKV pandemic.Chikungunya
virus (CHIKV) causes severe, debilitating, often chronic arthralgia with high attack rates …