The FDA and the CDC are recommending a pause in the use of Ixchiq (Chikungunya Vaccine, Live) in individuals 60 years of age and older while the Agencies investigate postmarketing reports of serious adverse events, including neurologic and cardiac events, in individuals who have received the vaccine

http://www.fda.gov/safety/medical-product-safety-information/fda-and-cdc-recommend-pause-use-ixchiq-chikungunya-vaccine-live-individuals-60-years-age-and-older