One of the surprises of the Caribbean outbreak is that the strain responsible isn't the one adapted to the tiger mosquito, but a different one, most likely originating in East Asia, says virologist Scott Weaver of UTMB. That's little consolation for most of the hemisphere, because A. aegypti is so widespread. But in the United States, A. aegypti occurs only in the southernmost parts of the country, which could limit the spread. There are no drugs for chikungunya, but several vaccine candidates are in various stages of development, and the Caribbean outbreak has revived industry attention, Weaver says. Weaver's own team has designed a live vaccine, based on a weakened version of the chikungunya virus, licensed to Japanese pharma company Takeda. Animal studies suggest that one shot of the vaccine will provide long-lasting protection, and Takeda is keen on beginning human studies, Weaver says.