<prompt> The infectivity of chickenpox lasts forTill the last scab falls off6 days after onset of rash3 days after onset of rashTill the fever subsides  <response>: Period of communicability: Chickenpox: 1 2 days before to 4 5 days after appearance of rash Measles: 4 days before to 5 days after appearance of rash Diphtheria: 14 28 days from disease onset Poliomyelitis: 7 10 days before and after onset of symptoms 