Explosions that destroy objects?

DoMan

I've made a game where you use different weapons to dispose of a disease. I tried to make a grenade type weapon, and after a certain time it spawns an explosion actor that grows, and then fades out. I made it so that when a diseased cell overlaps or collides with it it should destroy itself. However, this sometimes doesn't work. Does the change size behavior only change the graphics? Is the explosion too fast? Is there a better way of doing this?