Thermal inactivation of different measles virus strains.

The kinetics of thermal inactivation at 45 degrees C was investigated with different measles virus strains. The decrease of virus infectivity was determined by plaque counting test. The inactivation velocity of strains Schwarz, Moraten, Woodfalk, L16/SSW, L16/Moscow, and L16/S3 based on regression curve analysis (virus titres by time) allowed to divide them into 3 categories according to temperature sensitivity. Our results showed that development of a thermostable measles vaccine does not require selection of a thermoresistant virus variant if certain conditions for virus harvest are fulfilled.