Analysis Price comparisons. To compare drug prices in Brazil to those in other middle and low-income countries, we examined Brazil’s 2006 PPPY prices alongside prices reported by the 2006 WHO Price Reporting Mechanism, the Clinton Foundation and MSF. Prices for patented ARVs in Brazil reflect price negotiations that have taken place since 1998. Reported percentage price declines for efavirenz and nelfinavir are based on the price differences between the year the drug was launched in Brazil and 2006 prices. Reported percentage price declines for lopinavir/r, atazanavir, and tenofovir are based on the initial price offered by the pharmaceutical company prior to the drug’s launch in Brazil and 2006 prices. To constrain price comparisons to include only those drugs meeting international quality and efficacy standards, whenever possible we restricted our analysis to drugs that had been approved by either the WHO Prequalification System or the US Food and Drug Administration. Both agencies require bioequivalence testing and good manufacturing, laboratory, and clinical practices [41,42]. To make price comparisons for the last year for which data were available in Brazil, we ended our comparative price analysis in 2006.