<prompt> In house with 9 susceptible individuals 1 gets infected and other two get infected after two days what is the secondary attack rate -25335065  <response>: Ans. is a i.e., 25 SARNo of exposed persons developing disease withinthe range of the incubation period---Total number of exposedsusceptible contactx 100o The important features of SAR : -The primary case is excluded from both the numerator and denominator.Denominator is restricted to susceptible contacts of primary case.In denominator, person should be suscetible - Immune person to disease are not susceptible to develop the disease, So they are excluded.Disease should develop within the range of incubation period.o In this questionPrimary case -1Susceptible contacts - 8 9-1Number of susceptible developing disease secondary cases - 2 Thus SAR 28x 100 25 