1. Summary of included studies.
| Study ID | Study design | Country | Participants | Intervention | Comparison | Duration of intervention | Vaccine target |
| Cates 2014 | Non‐randomised trial | USA | Parents and health providers | Multi‐component providers and parents | Usual practice | 3 months | HPV |
| Diclemente 2015 | Randomised trial | USA | Adolescents | Health education | Usual practice | 30 minutes | HPV |
| Fiks 2016 | Controlled before‐after study | USA | Health provider | Provider education with performance feedback | Usual practice | 1 month | HPV |
| Gargano 2015 | Randomised trial | USA | Parents | Health education | Usual practice | 2 months | Tdap, MCV, HPV, Influenza |
| Grandahl 2016 | Cluster‐randomised trial | Sweden | Adolescents | Health education | Usual practice | 30 minutes | HPV |
| Mantzari 2015 | Randomised trial | UK | Adolescents | Financial incentives | Usual practice | 6 months | HPV |
| Paskett 2016 | Randomised trial | USA | Parents and health providers | Multi‐component providers and parents | Usual practice | — | HPV |
| Perkins 2015 | Cluster‐randomised trial | USA | Adolescent and health providers | Multi‐component provider intervention | Usual practice | 1 months | HPV |
| Rickert 2015 | Randomised trial | USA | Parents | Health education | Usual practice | 1 hour | HPV |
| Schwarz 2008 | Randomised trial | USA | Adolescents and caregivers | Health education plus financial incentives | Usual practice | 1 hour | HepB |
| Skinner 2000 | Randomised trial | Australia | Adolescents | Complex health education | Simplified health education | 1 hour | HepB |
| Staras 2015 | Non‐randomised trial | USA | Adolescents | Health education | Usual practice | 3 months | HPV |
| Szilagyi 2015 | Randomised trial | USA | Health providers | Provider prompts | Usual practice | 2 months | Tdap, MCV, HPV, Influenza |
| Wilson 2005 | Non‐randomised trial | USA | Adolescent | Mandatory school entry vaccination | Usual practice | — | HepB, Td, and MMR |
| Winer 2016 | Cluster‐randomised trial | USA | Parents | Health education | Usual practice | 30–40 minutes | HPV |
| Watson‐Jones 2012 | Cluster‐randomised trial | Tanzania | Adolescents | Class‐based vaccination | Age‐based vaccination | 12 months | HPV |
HepB: hepatitis B virus; HPV: human papillomavirus; MCV: meningococcal conjugate vaccine; MMR: measles–mumps–rubella; Td: tetanus–diphtheria; Tdap: tetanus–diphtheria–acellular–pertussis.