Ritonavir boosts the lopinavir levels, helping lopinavir to work better at controlling HIV infection. The HIV virus proliferates within the body’s cells, spreading the infection from one cell to another. During this process, the virus makes new proteins, some of which are structural proteins and some enzymes, such as protease. Lopinavir blocks the activity of protease, controlling the infection and reducing the number of viruses in the body. Remember, Generic Kaletra does not prevent HIV transmission and it does not cure HIV/AIDS.