1. Summary of related published reviews focused on the demand side of childhood vaccination.

Author/ date	Title	Focus	Methodology
Dube 2018	Underlying factors impacting vaccine hesitancy in high‐income countries: a review of qualitative studies	Focuses on the determinants of parents’ attitudes and behaviours towards childhood vaccination. Only includes studies from HICs	Qualitative
Larson 2018b	Measuring trust in vaccination: a systematic review	Focuses specifically on the issue of trust and how different dimensions of trust interact to influence vaccine acceptance, hesitancy and refusal. Considers vaccines for both children and adolescents	Mixed methods, includes both quantitative and qualitative studies
Ames 2017b	Parents’ and informal caregivers’ views and experiences of communication about routine childhood vaccination: a synthesis of qualitative evidence	Focuses specifically on views and experiences of communication interventions about childhood vaccinations	Qualitative
Karafillakis 2017	The benefit of the doubt or doubts over benefits? A systematic literature review of perceived risks of vaccines in European populations	Focuses on perceptions of the benefits and risks of vaccines. Only includes studies from Europe and considers vaccines for all age groups	Mixed methods, includes both quantitative and qualitative studies
Carlsen 2016	The swine flu vaccine, public attitudes, and researcher interpretations: a systematic review of qualitative research	Focuses on attitudes towards a vaccine given in response to a pandemic and also considers all age groups	Qualitative
Corben 2016	To close the childhood immunisation gap, we need a richer understanding of parents’ decision‐making	A narrative review focusing on factors influencing parents’ vaccination decision‐making and interventions to increase vaccination uptake	Mixed methods, includes both quantitative and qualitative studies
Tauil 2016	Factors associated with incomplete or delayed vaccination across countries: a systematic review	Focuses on the factors influencing adherence to routine childhood immunisation schedule. Considers both demand‐ and supply‐related factors	Quantitative
Larson 2014	Understanding vaccine hesitancy around vaccines and vaccination from a global perspective: a systematic review of published literature, 2007‐2012	Focuses on the factors affecting vaccine hesitancy and its determinants	Quantitative
Williams 2014	What are the factors that contribute to parental vaccine‐hesitancy and what can we do about it?	Focuses on the barriers to vaccination reported by vaccine‐hesitant parents and the current evidence on strategies to address parental vaccine hesitancy. Considers vaccines for both children and adolescents	Quantitative
Yaqub 2014	Attitudes to vaccination: a critical review	Focuses on vaccination attitudes among the public and healthcare professionals. Only includes studies from Europe and considers vaccines for all age groups	Mixed methods, includes both quantitative and qualitative studies
Dube 2013	Vaccine hesitancy: an overview	A narrative review providing an overview of the phenomenon of vaccine hesitancy and the possible causes of its increase, and the determinants of individual vaccination decision‐making. Only includes studies from HICs	Unclear as it includes multiple studies and reviews and does not specify the methods for each
Favin 2012	Why children are not vaccinated: a review of the grey literature	A review of grey literature focusing on the reasons for childhood incomplete or non‐vaccination. Considers both demand‐ and supply‐related factors	Mixed methods, includes both quantitative and qualitative studies
Rainey 2011	Reasons related to non‐vaccination and under‐vaccination of children in LMICs: findings from a systematic review of the published literature, 1999–2009	Focuses on the factors related to the under‐vaccination and non‐vaccination of children. Considers both demand‐ and supply‐ related factors and only includes studies from LMICs	Mixed methods, includes both quantitative and qualitative studies
Brown 2010	Factors underlying parental decisions about combination childhood vaccinations including MMR: a systematic review	Focuses on the factors influencing vaccination decisions. Only includes studies from HICs and considers only combination MMR vaccines	Mixed methods, includes both quantitative and qualitative studies
Falagas 2008	Factors associated with suboptimal compliance to vaccinations in children in developed countries: a systematic review	Focuses on the factors associated with suboptimal childhood vaccination compliance. Only includes studies from HICs	Quantitative
Jackson 2008	A systematic review of decision support needs of parents making child health decisions	Focuses on all parental decision‐making about child health, not just vaccination	Mixed methods, includes both quantitative and qualitative studies
Nagaraj 2006	Does qualitative synthesis of anecdotal evidence with that from scientific research help in understanding public health issues: a review of low MMR uptake	Focuses on professional and parental factors underlying uptake of MMR only, and only includes studies from HICs	Qualitative, includes technical and non‐technical anecdotal literature
Mills 2005	Systematic review of qualitative studies exploring parental beliefs and attitudes toward childhood vaccination identifies common barriers to vaccination	Focuses on parental beliefs and attitudes toward childhood vaccination and associated barriers to paediatric immunisations. Only includes studies from HICs	Qualitative
Sturm 2005	Parental beliefs and decision making about child and adolescent immunisation: from polio to sexually transmitted infections	A narrative review focusing on the influence of parental attitudes and beliefs on vaccine decision‐making. Only includes studies from HICs and considers vaccines for children and adolescents	Mixed methods, includes both quantitative and qualitative studies
Roberts 2002	Factors affecting uptake of childhood immunisation: a Bayesian synthesis of qualitative and quantitative evidence	Focuses on the factors that affect the uptake of recommended childhood immunisations. Only includes studies from HICs	Mixed

HICs: high‐income countries; LMICs: low‐ and middle‐income countries; MMR: measles, mumps, and rubella