Promoting Vaccination Take-up at the Last Mile: Evidence from a Randomized Controlled Trial in Rural Indonesia

We conduct a cluster randomized experiment that varies the type of vaccine ambassadors—health care workers, local leaders, and laypersons—at the village level. Each ambassador—recruited from local communities—is tasked to deliver the same information contents on COVID-19 and COVID-19 vaccines (e.g., benefits and risks of taking up vaccines) to participants. To increase the chance of success, ambassadors will also use participants' personal information from baseline survey, such as reasons and barriers to vaccination, to tailor a more targeted approach for each participant. Ambassadors use interpersonal behavioral communication change approach as their communication strategy.

We will have three treatment groups, where each group only differs in terms of the types of ambassadors---they deliver the same information contents.

1. Treatment 1: In this group, local health cadres will serve as ambassadors
2. Treatment 2: In this group, local eminent persons--selected through nominations by villagers--will serve as ambassadors
3. Treatment 3: In this group, local laypersons will serve as ambassadors

We do not have pure control group in this study because we want to combat misinformation in every village.
We consider Treatment 3 as the control group for estimation purpose.

All ambassadors are tasked to deliver information contents that have been prepared by our research team, such as the efficacy of first and second dose of vaccine, personal benefits of vaccines, social and economic benefits of vaccines, social norms of vaccination, and other practical topics of vaccination (e.g., vaccine types, number of doses, local vaccination sites). All ambassadors will visit each participant personally twice within two-week period. First visit involves information session. Second visit is aimed to ask for respondents' intention and commitment to get vaccinated. During the second visit, to enhance information retention, ambassadors will deliver a pamphlet summarizing most important information about COVID-19 vaccines.

More detailed explanation on each treatment below.

Treatment Group 1 (Health Cadres) -- In villages assigned to this treatment, we will recruit health cadres that operate at the village level. In terms of qualification and education credentials, these health cadres differ from health workers (doctors and nurses)—cadres usually do not have medical or nursing degrees. They are generally volunteers that assist community health related agendas, such as implementation of child immunization. Unlike doctors and nurses, most villages have health cadres.

Treatment Group 2 (Nominated)---In villages assigned to this treatment, we will leverage village social networks to recruit a central individual as an ambassador. We asked respondents in each village to nominate and identify three individuals who they perceive as the most respected, trusted, and credible at disseminating health or important information in their village. We then approached and recruited the individual that receives the most nominations as an ambassador. If he/she declined, we approached the second nomination and so on until we get an ambassador.

Treatment group 3 (Laypersons)--In villages assigned to this treatment, we approached and recruited a layperson to become an ambassador in a randomly assigned village. To distinguish between treatment groups, we did not recruit layperson ambassadors from the health cadres.

2022-06-09

2022-07-06

1. Vaccination uptake

2. Vaccination intention: willingness to get vaccinated and registered for vaccination but declined

3. Vaccination status of others

1. Vaccination uptake
Measures the actual vaccination. Binary variable that equals to one if participants report having received the first and/or second dose of vaccine (verified by physical or digital proof).

2. Vaccination intention

A. Willingness to get vaccinated
Measures the degree of vaccination intention, likert scale variable (1-5). This variable will be normalized to have 0-1 support.

B. Registered for vaccination but declined
Measures vaccination intention but vaccination fails to materialize due to health or other reasons. Binary variable that equals to one if participants report having registered for vaccine but declined by health workers for health or other reasons.

3. Vaccination status of others
Measures potential spillover effects of the intervention on reported vaccination status of household members and friends/relatives.

Household vaccination rate ranges between 0 and 1.

Vaccination status of close friends/relatives is constructed from responses to "How many people in your personal network (close family and/or friends) have been vaccinated against COVID-19?" (conditional on responding “yes” to "Have any of your relatives / neighbors / acquaintances been vaccinated since our last visit?"). This variable is measured using likert scale 1 (few) to 4 (all). This variable will be normalized to have 0-1 support.

1. Compliance to COVID-19 health protocols

2. Post-intervention COVID infection

3. Mental health: general mental health status and mental health status attributed to COVID-19

4. Perceived quality of the ambassadors and intervention

5. Participation during information session

6. Knowledge about COVID-19 and vaccines

7. Beliefs about COVID-19 and vaccines

1. Compliance to COVID-19 health protocols
Index variable constructed from responses to questions on hand-washing, mask-wearing, and maintaining physical distance.

2. Post-intervention COVID infection
Binary variable that equals to one if respondents report getting infected with COVID after the intervention.

3. Mental health: general mental health status and mental health status attributed to COVID-19

A. General mental health status
Index variable constructed from questions on non-specific cause of depression and other questions.

B. Mental health status attributed to COVID-19
Index variable constructed from questions on depression and other questions driven by fear of COVID-19.

4. Perceived quality of the ambassadors and intervention
Index variable constructed from questions on participants' self-assessment on the quality of information delivery by the ambassadors and intervention as a whole.

5. Participation during information session
Index variable constructed from questions on participants' participation, such as number of correct information on knowledge on COVID-19 and vaccines.

6. Knowledge about COVID-19 and vaccines
Index variable constructed from questions on health belief model related to knowledge about COVID-19 and vaccines, such as benefits and risks of COVID-19 vaccines.

7. Beliefs about COVID-19 and vaccines
Index variable constructed from questions on health belief model related to beliefs on vulnerability to catching COVID-19 and barriers to COVID-19 vaccines, among other things.

We conduct a cluster randomized experiment that varies the type of ambassadors at the village level. Other than local eminent person ambassadors, which are nominated by participants, health cadres and layperson ambassadors are randomly selected using list provided by village officials.

Cluster level randomization (village level) by computer software. Within each cluster, eligible population (list provided by village officials) will be randomly selected by computer software.

Village

Yes

300 Villages

3,600 Observations

Each treatment arm consists of 100 villages and roughly 1200 individuals.

Promoting Vaccination Take-up at the Last Mile: Evidence from a Randomized Controlled Trial in Rural Indonesia