Efficacy of exogenous interferon treatment initiated after onset of multiplication of vesicular stomatitis virus in the brains of mice.

Initiation of treatment with potent interferon preparations (6-4 x 10-6 units per dose) 4 days after intranasal inoculation of VSV (at a time when virus has already multiplied in the brains of most mice) resulted in a marked increase in mouse survival. In a series of 6 experiments only 11 to 18% of control mice survived whereas 52% of interferon treated mice survival. These results suggest the usefulness of exogenous interferon even when treatment is begun late in the course of an acute virus disease.