Using Behavioral Insights to Increase the Demand for Childhood Vaccination in Low Resource Settings: Evidence from a Randomized Controlled Trial in Lebanon

"This study highlights the importance of integrating behavioral insights into vaccination campaigns and programs, especially in low resource settings, to ensure that more children can benefit from life-saving vaccines."

Lebanon has historically maintained high immunisation coverage rates for most routine vaccines. However, an increase in poverty rates, coupled with an influx of over a million refugees in 2011, posed significant challenges to the national immunisation programme. In response, the Ministry of Public Health (MoPH) Lebanon, in collaboration with United Nations Children's Fund (UNICEF), launched an accelerated immunisation activities (AIA) programme in November 2017. Despite this demand generation effort, uptake among refugee and host community households remained low. This study investigates the barriers that prevent households in low coverage areas from vaccinating their children, and it evaluates a behaviour change intervention that uses nudging in an effort to overcome the identified social, perceptual, and cognitive barriers.

The paper begins by describing the AIA programme. In addition to the support offered to primary healthcare centres (PHCs), the programme employed a community-based outreach approach to (a) identify un- or under-vaccinated children, (b) educate and raise awareness of caregivers on the importance of childhood vaccination, (c) collect children's vaccination records, (d) refer children missing vaccines to the nearest participating PHC, and (e) follow up with caregivers to ensure that full immunisation is achieved.

The study was implemented between August 2018 and March 2019 in seven cadastres within three urban districts in Lebanon: Beirut, Baabda, and Matn. A mixed-methods approach, including stakeholder interviews and field observations, was employed to identify the main barriers to vaccination. Thereafter, a cluster randomised trial was conducted to evaluate the impact of the intervention (a visual planning aid comprising five behaviour change techniques, or nudges) on vaccine uptake. A total of 12,332 un- or under-vaccinated children from 6,160 households (3,045 (49.4%) control households; 3,115 (50.6%) treated households) were reached during the trial.

The most prevalent barriers identified were forgetfulness and neglect, as most beneficiaries lived in poverty, and therefore had diverted priorities. To offset these barriers, a visual planning aid in the form of a calendar was designed. The planning aid consisted of five nudges: (i) factual statements about the uptake of vaccination by other beneficiaries (norms/social proof); (ii) a non-binding pledge by parents to vaccinate their children (commitment); (iii) an implementation intention plan, whereby parents would specify the date and location in which they will vaccinate their children (implementation intentions); (iv) the MoPH's guarantee of the quality and effectiveness of the vaccines (messenger); and (v) a request to place the calendar somewhere visible (salience). Table 2 in the paper summarises the identified behavioural barriers and nudges used to offset them.

Outreach teams assigned to the treatment group were given copies of the calendar to distribute to eligible households alongside their standard outreach activities. Meanwhile, the control group continued to use the standard outreach approach. Each group completed separate training sessions to remind them about the AIA implementation protocols, introduce them to the new procedures required by the intervention, and run mock outreach activities. The teams were spot-checked during the implementation period to identify and mitigate implementation and data collection issues.

Compared to the control group, treated households were 6.7 percentage points (pp) more likely to vaccinate at least one child (adjusted 95% confidence interval (CI): (1.5 pp, 11.9 pp), p < 0.05). The average uptake among households receiving the calendar was 20.2% versus 13.5% in the control group. The demand for vaccination increased 1.8 pp for every additional unvaccinated child in the household (adjusted 95% CI: (0.6 pp, 2.9 pp), p < 0.01). This result was statistically significant and practically meaningful, with at least 220 additional households (390 additional children) receiving vaccines as a result of the intervention (outreach + visual planning aid).

Overall, vaccinated children reported to a health centre within 13.5 days (standard deviation (SD) = 11.6 days) following a household visit. Treated children were on average 1.6 days earlier to vaccinate compared to those in the control group, averaging 13.0 days (SD = 10.85) compared to 14.6 days (SD = 12.8), respectively (95% CI: (0.20 days, 3.0 days), p < 0.01).

Nationality was a significant determinant of overall uptake, such that Lebanese households were 3.1 pp less likely to demand vaccination relative to non-Lebanese households (95% CI: (-5.0 pp, -1.0 pp), p < 0.01). However, the study found no significant difference in the treatment effect between Lebanese and non-Lebanese households. Furthermore, in line with previous findings from Lebanon, the child's gender was not a significant predictor of vaccination uptake, with households equally likely to vaccinate boys and girls.

In conclusion, this study "demonstrates how simple, low-cost nudges such as intention-implementation plans, norms, and commitments delivered in an appealing visual planning aid can be effective at addressing perceptual, social, and cognitive barriers to increase the demand for childhood vaccination....These findings have important implications for future vaccination programs in Lebanon and other similar contexts, and can help inform the design of future vaccination programs to ensure that more children receive life-saving vaccines."