Systematic maps draw on the same rigorous and transparent methods used for systematic reviews of effects, but focus on documenting and describing the range of interventions available rather than their effects [27, 28]. We will search multiple databases for literature describing or evaluating communication interventions related to childhood vaccination, selecting on key criteria of communication intervention (defined comprehensively as per the Cochrane Consumers & Communication Review Group scope ) and childhood vaccination. The databases of primary focus will be the Cochrane Central Register of Controlled Trials (CENTRAL) and MEDLINE. For each communication intervention identified, we will extract descriptive information on the aim of the intervention, population(s) targeted, intervention content and tools used to deliver the intervention, evaluation design (where applicable), and outcomes assessed . We will also link these interventions to known barriers to improved vaccination uptake [8, 30] and examine relationships between intervention types and delivery context.
The construction of the interventions map will entail extracting and mapping the following data from all included studies, with particular attention paid to capturing information about interventions in a systematic and structured way [29, 31]:
1. Communication barriers identified (if any)
2. Population features: population group; setting of vaccination services (i.e., country and region, urban, or rural); vaccination delivery strategy, details of vaccine dose and coverage; and age of infants or children
3. Communication intervention features: intervention purpose; direction of communication ; parties involved; content of communication; format and delivery mode; deliverer (i.e., service type or personnel); training required; setting; frequency or timing of communication; and cost
4. Outcome features: main outcomes measured (where applicable); and side effects.
Rigorous effects studies (i.e., controlled trials) will be evaluated on additional characteristics using existing checklists. These data will allow us to describe where, in relation to the interventions map, robust evidence of effectiveness is available, informing later project sub-studies.