In a 6 membered family, there are two parents and four children all aged between 2-6 years. On eof the children is completely immunized for his age, whereas other 3 siblings are totally unimmunized. One of the unimmunized child developed measles. 6 days later 2 other children developed measles. SAR is?

Ans. is 'd' i.e., 100% o In this family of 6 members: Parents are not susceptilble because adults are usually not susceptible to measles. 1 child is immunized --> Not susceptile for measles Remaining 3 children are non-immunized --> susceptible for measles. All 3 susceptible children developed measles within one incubation period (Incubation period of measles is 23 weeks)