Calculation of the frequency of congenital rubella syndrome in Poland.

The annual number and incidence of congenital rubella syndrome (CRS) in Poland was evaluated by means of a methematical model and on the basis of serological studies. In its principles this model describes the infectious kinetics of rubella by the formula y = 1--e-at, where "y" is the rate of immune persons, "a" is a parameter representing the transfer of susceptibles to immunes and "t" is age. The calculated incidence of congenital rubella syndrome resulted in average values of 0.15 to 0.38%, i.e. 15 to 38 CRS cases among 100,000 children born to mothers primarily infected by rubella virus during the first trimester of pregnancy.