Beneficial effects of human viruses

In keeping with the theme of this Yale-China symposium, we discuss some unexpected dividends which have been derived from the basic study of five viruses to which man has been exposed. Inquiring into the behavior of these viruses for their own sake has not only produced an increase in basic understanding of biologic processes, but has provided concepts and techniques which will broaden our knowledge of the etiology, pathogenesis, and treatment of human diseases which are unrelated to viruses.