Badge of Infamy

Badge of Infamy is a juvenile science fiction novel written by American writer Lester del Rey. 

In the future, powerful unions called lobbies control much of society. One of the most powerful lobbies is the medical lobby, which following a pandemic that spread across earth, has required all medicine from being practiced only by authorized lobby members and only in approved lobby facilities. Daniel Feldman was once a doctor but has now become a pariah due to his breach of these rules. Trying to escape the shame he travels to Mars, where he discovers a disaster threatening billions of lives.