in the present study the distribution of rubella hemagglutination inhibition (hi) antibody titer in the sera of 1486 women of 18 to 25 years old residing in tehran were examined. sera were pretreated with acid washed kaolin and pigeon red blood cell. titers below 1:10 and in some studies below 1:20 are considered nonimmune to rubella. our results show that 10, 29% of studied population had hi a...