Yes, of course! One of the alkaloids in Olive leaf is called oleuropein, and it seems to have an effect on pathogenic microbes such that they are rendered inert in your body.
The theory of virology goes like: a virus cannot replicate on its own and must infect a host cell, which it turns into a little replication factory. Theoretically, oleuropein changes the outer protein layer of the virus so that it is unable to penetrate healthy cells in your body. This ...