Core Outcome Measures in Effectiveness Trials

Identification of preliminary core outcome domains for communication about childhood vaccination: An online Delphi survey

General Information

Communication interventions for childhood vaccination are promising strategies to address vaccine hesitancy, but current research is limited by the outcomes measured. Most studies measure only vaccination-related outcomes, with minimal consideration of vaccine hesitancy-relevant intermediate outcomes. This impedes understanding of which interventions or elements are effective. It is also unknown which outcomes are important to the range of stakeholders affected by vaccine hesitancy. Outcome selection shapes the evidence base, informing future interventions and trials, and should reflect stakeholder priorities. Therefore, our aim was to identify which outcome domains (i.e. broad outcome categories) are most
important to different stakeholders, identifying preliminary core outcome domains to inform evaluation of three common vaccination communication types: (i) communication to inform or educate, (ii) remind or recall, and (iii) enhance community ownership.

We conducted a two-stage online Delphi survey, involving four stakeholder groups: parents or community members, healthcare providers, researchers, and government or non-governmental organisation representatives. Participants rated the importance of eight outcome domains for each of the three communication types. They also rated specific outcomes within one domain (‘‘attitudes or beliefs”) and provided feedback about the survey.

Collectively, stakeholder groups prioritised outcome domains differently when considering the effects of different communication types. For communication that aims to (i) inform or educate, the most important outcome domain is ‘‘knowledge or understanding”; for (ii) reminder communication, ‘‘vaccination status and behaviours”; and for (iii) community engagement communication, ‘‘community participation”. All stakeholder groups rated most outcome domains as very important or critical. The highest rated specific outcome within the ‘‘attitudes or beliefs” domain was ‘‘trust”.

This Delphi survey expands the field of core outcomes research and identifies preliminary core outcome domains for measuring the effects of communication about childhood vaccination. The findings support the argument that vaccination communication is not a single homogenous intervention – it has a range of purposes, and vaccination communication evaluators should select outcomes accordingly.

Communicate to Vaccinate (COMMVAC) 2 Project

Jessica Kaufman (PhD candidate and lead investigator for this study)
Sophie Hill (supervisor and COMMVAC project partner)
Rebecca Ryan (supervisor)

Simon Lewin (COMMVAC 2 principal investigator)
Xavier Bosch-Capblanch (project partner)
Claire Glenton (project partner)
Julie Cliff (project partner)
Angela Oyo-Ita (project partner)
Artur Manuel Muloliwa (post-doctoral researcher)
Afiong Oku (PhD candidate)
Heather Ames (PhD candidate)
Gabriel Rada (project partner)
Yuri Cartier (project partner)


Further Study Information

January 2014 - 2015
Funding source(s):
The work of all authors except RR is supported by the Global Health and Vaccination Research (GLOBVAC) program of the Research Council of Norway (COMMVAC 2 project grant number 220873). SL also receives funding from the South African Medical Research Council. RR is funded by the National Health and Medical Research Council (Cochrane Review Group support 2013–2016).

Health Area

Disease Category
Child health
Public health

Disease Name

Target Population

Age Range
0 - 4


Nature / type of Intervention


Delphi process
Focus group(s)
Literature review

Stakeholders Involved

Clinical experts
Consumers (caregivers)
Governmental agencies

Study Type

COS for clinical trials or clinical research

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