“…A detailed explanation is given elsewhere[ 20 ]. Briefly, the population of this poor, rural area is around 900,000 and subject to the highest infant mortality rate in the country at around 121 per 1,000 live births compared to national average of 68 per 1,000 live births[ 21 , 22 ]. Like the rest of Tanzania, the health system in the project area comprises a network of tiered public and private facilities where IPTi is delivered alongside Expanded Programme on Immunization (EPI) services.…”