Résumé
When, in 2010, a new PMTCT (Prevention of Mother-to-Child Transmission) strategy replaced the provision of infant formula to mothers living with HIV by a prophylaxis based on antiretrovirals, some Senegalese couples decided to purchase infant formula on their own, thereby risking 'medically induced poverty'. This case study analyzes the emergence of a situation of economic vulnerability generated by a public health policy that is nevertheless globally appropriate in terms of accessibility and epidemiological effectiveness. Because of the gap between the rationales of institutions at the international and national levels and those of people 'on the ground', a strategy that has been defined as progress in terms of equity is interpreted as a regression creating inequality. This situation stems from several determinants analyzed in this article: rapid and poorly managed transition from one strategy to another, different perceptions of acceptable risk levels, and inadequate communication of information by care providers.