Measles epidemic can be anticipated when propoion of susceptible children in a community reaches -: (A) 20%, (B) 40%, (C) 60%, (D) 80%
Answer is B. Measles tends to occurin epidemics when the propoion of susceptible children reaches about 40% Reference; Park&;s Textbook of preventive and social medicine, 24th edition.Pg no. 156