The cover was colorful and had a picture of the back of a young man walking with a bike.
The story starts out with a teenage male living with his very paranoid father who has managed to keep them both alive with very strict rules in order to stay safe, not just from the virus (I think they called it the ceph/seph...sp?) but from people who once infected became irrational and violent. The father is exposed and sets into motion the plan for the son to reach a safe haven. The son manages to reach a safe place but is so unhappy with it after arriving that he leaves.
The book is actually quite short. I bought it in the mid to late 80s used at the Hobbit in Santa Monica. Read it till it fell apart and would love to remember the title so I can get a new copy.