Fig. 3.In infections with the human immunodeficiency virus (HIV), there are different types of infected cells. Productively infected cells start producing virus particles immediately after they get infected. Their half-life is about 2 days and they produce 99% of the virus particles present in a patient. Latently infected cells can contain inactive virus waiting to be reactivated to become productively infected cells. The estimated half-life of latently infected cells is between 10 and 40 days. Chronically infected cells continuously produce free virus particles, albeit at a slow rate. Their half-life is similar to the half-life of latently infected cells. About 90% of HIV-infected cells in the blood of patients contain defective pro-virus, which is incapable of initiating virus production. The half-life of these cells is about 100 days. Knowledge of the turnover rates of different types of infected cells is crucial for evaluating the effect of antiviral therapy and estimating the chances of virus eradication from infected patients.