TLS Online TPP Program

#Question id: 11353


Prior to the availability of a measles vaccine, outbreaks of measles occurred at two-year intervals, why?

#Section 4: Behavioural Ecology
  1. Measles outbreaks occurred during hard winters, which happen every other year
  2. Two years were required for accumulation of enough susceptible infants
  3. Immunity to measles wore off in about two years
  4. Two years were required for the measles virus to disperse from tropical sources