The degree of sensitivity to varying dilutions of a poison ivy antigen was established by patch tests in seven individuals. Administration of the live, attenuated measles virus vaccine (Schwarz) to this small group of subjects resulted in a temporary reduction of sensitivity, most marked (33% of control values) between the third and sixth weeks postimmunization. At nine weeks, the sensitivity was returning to preimmunization levels. Five control subjects showed no change in their degree of sensitivity.
Blumhardt R, Pappano JE, Moyer DG. Depression of Poison Ivy Skin Tests by Measles Vaccine. JAMA. 1968;206(12):2739-2741. doi:10.1001/jama.1968.03150120073026