The Gilchrist and M-33 strains of rubella virus exposed in the frozen state to (137)Ce or (60)Co were inactivated exponentially according to "one hit" kinetics. There was no difference in the radiosensitivity of the two strains. Experimental D(37) values for both strains ranged from 1.9 x 10(5) to 2.9 x 10(5) rads, and computed radiosensitive molecular weights ranged from 2.6 x 10(6) to 4.0 x 10(6) daltons.
