IXCHIQ - a live-attenuated chikungunya virus vaccine: 10-30% have mild-moderate adverse effects, w/ headache, fatigue, & myalgia. <3% have severe AEs. Rare reports of encephalitis in elderly post Ixchiq, due to type I IFN-neutralizing autoantibodies (same w/ yellow-fever Vax) https://t.co/3VlZCd4sGc