Table 2 Study inclusion criteria. Caption: abstracts and full texts were screened independently by two authors using the following criteria

Study population

Any child/adolescent 9–19 years old, recruited from the community or a cohort of vaccinees, care-givers or care-providers

Geographical setting

No restriction

Vaccine

Any vaccine administered to the study population in a schedule including more than one dose within the same year

Vaccine delivery

Routine vaccine delivery; studies excluded if an outbreak/campaign setting/non-routine delivery

Outcome

Completion or non-completion of (or ‘adherence to’) the intended multi-dose vaccine schedule within 1 year of follow-up

Comparison

Individuals or groups who initiated vaccination (i.e. received dose 1), and completed the vaccine series (i.e. received the final dose) within 1 year, compared to those who initiated the vaccine series but did not receive the final dose within 1 year.

Exposure

Any characteristics of individuals, communities, or programmatic or contextual factors investigated for an association with adherence/completion

Study design

Any study design with data on and analysis of factors predicting completion of a multi-dose vaccine in routine settings

Data

Some estimate of the completion rate achieved must be available