The Prevention of Mother-to-child Transmission (PMTCT) of HIV program in Zambia has undergone several policy iterations over the past 10 years. This qualitative study aimed to contribute towards addressing this knowledge gap by analysing the evolution and actors' influence during the policy process using the Walt and Gilson policy triangle as our evaluation framework. Document review and key informant interviews with policy makers were undertaken to identify the contextual factors that had shaped the PMTCT policy evolution in Zambia. Overall, the study revealed that over the past decade, at least five PMTCT policy changes have occurred, averaging three years per policy with extensive overlap between policies. This resulted in more than two policies being implemented at a given time. Pressure from the international community and scientific evidence were the main drivers of policy change in Zambia, with local actors being mainly reactive. Among international agencies, UNICEF and WHO were the key actors who had driven the policy changes as they had the power and resources. The rapid changes, negatively impacted the health system, disrupted service delivery, which was unprepared to effectively and efficiently shift from one policy to another.
Keywords: Health Policy analysis; Health system; Option B+; Prevention of Mother to Child Transmission; Zambia.