<prompt> True about measles outbreak ?Occurs if propoion of susceptible children is 20Infects 50 children in virgin communityVaccination given at 6 monthsEvery 6-7 years  <response>: Ans. is c i.e., Vaccination given at 6 months Epidemic of measles occur if propoion of susceptible children is 40. If measles is introduced in a virgin community, it infects 90 of children. Measles vaccine is given at the age of a months, but age can be lowered to 6 months in epidemics. Measles shows a cyclic trend with epidemic every 2-3 years. 