<prompt> In a village of 100 children, 60 are immunized against measles. One child travelled outside and returned with measles and infected other 26 children. What is the secondary attack rate67275080  <response>: Ans. is a, i.e 67 Secondary attack rate : No. of exposed persons developing the disease within the range of incubation period following exposure to the primary case. SAR No. of exposed persons developing the disease within the range of incubation period x 100 Total no. of exposedsusceptible contactsTotal no. of children 100Total no. of immunize 60No. of susceptible 39Since out of 40 unimmunized children one has already contacted the disease.No. of exposed persons developing the disease 26So SAR 26 39 x 100 2003 67 