 Accordingly, estimates from the period of the epidemic often were imprecise, tending to overestimate the overall number of cases.China did not begin to produce regular, systematic estimates of the prevalence of HIV/AIDS until 2003, doing so in conjunction with the United Nations, World Health Organization, and United States Centers for Disease Control.This initial estimate was tentatively 840,000 cases nationwide, but with a potential range of 430,000 to 1.5 million.