<prompt> True about varicella vaccine is ?Poorly immunogenicDuration 4-6 monthsAvoid salicylates for 4-6 weeksGiven to child 12 months when they do not have chicken pox  <response>: Ans. is c i.e., Avoid salicylates for 4-6 weeks A live attenuated varicella virus vaccine is safe and currently recommended between 12-18 months of age who have not had chicken pox.The vaccine is very immunogenic, sero-conversion occurs in 95 of children after a single dose.A duration of immunity is not known, but is probably 10 years. 