Discussion
DISEASE, MEASLES, BCC
This study was among the first trials in Africa to demonstrate a beneficial impact of a CCT intervention on child immunisation. Introduction of a single time point conditionality and provision of an enhanced home-based health record card had a highly significant positive impact on vaccination with improvements in both measles (MCV1) vaccination coverage and pentavalent series completion. The mHealth intervention was associated with an increase in household diet diversity, despite no evidence that knowledge had improved. To the best of our knowledge, this is the first study to demonstrate that mHealth interventions may improve household diet diversity when combined with a multipurpose UCT programme. However, no change in child diet diversity or any other primary outcome was observed, and there was no improvement in exclusive breastfeeding.The strong impact of cash transfer conditionality on uptake of vaccination services is consistent with other studies that have provided evidence that conditional transfers can enhance the use of health services and improve health outcomes [The selection and calculation of vaccination indictors for use in different studies is somewhat variable [Timely vaccination (also referred to as on-time vaccination or its reverse, delayed vaccination) is important to assess as delayed vaccination may lead to an increase in mortality and it increases the fraction of a population that requires vaccination in order to eliminate a disease [Achieving full vaccination is challenging in this context for a range of reasons, including weak health infrastructure, financial and human resource constraints, insecurity, a highly mobile population, as well as knowledge of and attitudes towards vaccination among caretakers. Evidence-based approaches to identify and remove barriers to vaccination are recommended as part of the Immunization 2030 global strategy [mHealth interventions have been demonstrated to have potential to improve multiple health indicators in low-income countries [The partnership between an NGO that had been operational in the area for many years and an academic institution with a strong track record in research in fragile contexts provided the necessary expertise to conduct this trial in challenging circumstances. Regular visits by the researchers to the field sites and the strong working relationships between the academic study coordinator and the NGO field coordinator were essential to the robust running of the trial. Periodic, monthly follow-up visits allowed close monitoring of participants with regular data collection and for the calculation of incidence as well as prevalence indicators.Use of both health record cards and caregiver recall to determine child vaccination status allowed for measurements to be made in the whole population sample. Only a small proportion possessed record cards at baseline, so if we had relied on card records only, it is likely to have resulted in selection of a biased sample. However, as record cards were issued as part of the CCT intervention, there was an unavoidable difference between the CCT and control arms in how vaccination data were collected after the baseline. It is therefore possible that the greater use of record cards in the CCT arm may have resulted in improved reporting of vaccinations and a resulting measurements bias. However, a recent study has demonstrated that while results from studies are inconsistent, parental recall compared to record-based data in East Africa may be reliable [Working with national companies experienced in production and broadcasting of mHealth messages helped to ensure the quality of the productions and allowed for messages to be recorded in both of the commonly used local languages. The process of mHealth message design was originally conceived as involving successive iterative cycles of design and message testing. Due to limitations in the available time, the intended testing process had to be curtailed, and, while messages were reviewed by the local study team, it was not possible to pretest all messages with participant volunteers before broadcast. Additionally, the BCC approach was ambitious, aiming to address multiple behaviours simultaneously, instead of focusing on few simple messages at a time. However, engagement with the mHealth messages remained high throughout the study, suggesting the general desirability of the messages among participants.The use of a 2 × 2 factorial design allowed the testing of 2 important interventions and was therefore cost-efficient. However, the study design also required a large number of comparisons and significance tests. The use of Holm–Bonferroni correction is recommended in situations where a large number of tests are required, and we adopted it for the analysis of this trial to reduce the risk of type 1 errors [Our data show that including a simple, one time point conditionality in a humanitarian cash transfer programme can increase the uptake of proven life-saving interventions, such as child vaccination. Further work to understand the contribution of home-based health record cards and how CHW interacted with them would be useful and contribute to optimising their design. Use of mHealth messages may be useful for increasing expenditure on food and diet diversity during cash transfer programmes. However, in this context, they failed to achieve any direct health benefits, despite achieving high engagement. Future studies should include iterative message design and intensive pretesting of content and format with participant volunteers. This would help to maximise the chances of utilising this potentially desirable modality to achieve health and nutrition impacts in this complex context.