Interventions Addressing Routine Childhood Immunization and Its Behavioral and Social Drivers

"[T]he current review fills an important learning gap by providing detailed summary of strategies from 142 impact evaluations."

To improve the evidence base on community engagement interventions, International Initiative for Impact Evaluations (3ie) commissioned several evaluations of such interventions under the its Innovations in Increasing Immunization Evidence Program. The present review builds on this existing work, available at Related Summaries, below, to provide a compendium of interventions that have been implemented in low- and middle-income countries (LMICs) to improve routine child immunisation outcomes. Furthermore, it analyses the barriers to vaccination uptake, classified using the World Health Organization (WHO)'s Behavioral and Social Drivers (BeSD) of vaccination framework, that were potentially addressed through these interventions. The paper also provides more information on key intervention features and implementation characteristics that are potentially useful for policy.

Experimental and quasi-experimental impact evaluations conducted in LMICs evaluating the effectiveness of interventions in improving routine immunisation of children aged 0-5 years or intermediate outcomes were included from 3ie's review of systematic reviews. Some additional impact evaluation studies published in recent years in select LMICs with large numbers of unvaccinated children were also included. Studies were coded to identify interventions and the barriers in the study context using the intervention framework developed in 3ie's Evidence Gap Map (EGM) and the BeSD of vaccination framework, respectively. The EGM framework broadly groups the interventions into caregiver-oriented, health system-oriented, community level, and policies and institutions. The BeSD framework divides the factors driving vaccine uptake into four broad drivers: (i) thinking and feeling, (ii) motivation, (iii) social processes, and (iv) practical constraints. In addition, political climate, natural calamity, migration, and socio-economic characteristics that may affect the uptake of vaccination were captured.

One hundred and forty-two impact evaluations were included to summarise the interventions. The majority of studies (n = 111) were published between 2011 and 2020, and the oldest study was published in the year 1986. Many included studies were conducted in India (n = 42), followed by Nigeria (n = 13).

The review found that evaluations of both standalone and multicomponent interventions have increased steadily since 2006. In the 2001-2010 decade, the studies mostly focused on evaluating effectiveness of informing, educating, and incentivising caregivers and training of health workers and health system strategic planning. In the 2011-2020 decade, there was an increase in interventions oriented toward the caregiver, health system, and community. Among the caregiver-oriented interventions, there was a sharp jump in evaluations of reminder and recall interventions overlapping with increasing usage of mobile phones. Among the health system-oriented interventions, there was a big increase in evaluations of those training health workers, carrying out home visits and outreach, and conducting health system strategic planning. In addition, there was a substantial number of evaluations of health management information system (HMIS)/dashboard interventions. Furthermore, there was a sharp increase in evaluations of community engagement interventions.

The included impact evaluations investigated effects of multiple standalone or multicomponent strategies on immunisation and its intermediate outcomes and one or more of the BeSD barriers to vaccination at various levels. These interventions are grouped based on the barriers they address and described in the paper. In brief:

• To address attitudinal and knowledge-related barriers to vaccination and to motivate caregivers, sensitisation and educational programmes, media campaigns, and monetary or non-monetary incentives to caregivers that may or may not be conditional upon certain health behaviours have been used across contexts.
• To improve knowledge of vaccination, its place, time, and schedule, automated voice messages and written or pictorial messages have been used as standalone or multicomponent strategies.
• Interventions used to improve service quality included training and education of health workers and providing monetary or non-monetary perks to them or sending reminders to them on different aspects of provision of vaccination services. Interventions like effective planning or outreach activities, follow-up of children, tracking of children that have missed vaccinations, pay-for-performance schemes, and health system strengthening have also been used to improve service access and quality.
• Interventions aimed at mobilising and collaborating with the community to impact social norms, attitudes, and empower communities to make health decisions have also been widely implemented. For example, the review identified 27 multicomponent strategies that included components of collaboration with select community groups or the whole community. Of these, 21 studies found that the intervention improved immunisation-related outcomes.

According to the researchers, this review allows the programme managers and policymakers who are exploring various strategies to improve vaccination uptake (i) to know which strategies have been tested and in which combinations, (ii) to know the context in which they have been tested, and (iii) to identify and explore the studies as their references are provided. The review also highlights critical areas for future policy-relevant research design. To understand how and why an intervention impacts an important barrier subsequently influencing uptake of vaccination, a well-developed theory of change (ToC) with carefully laid out impact pathways is helpful.