Door-to-door mobilization of COVID-19 vaccination in Kenya

Last registered on July 29, 2022


Trial Information

General Information

Door-to-door mobilization of COVID-19 vaccination in Kenya
Initial registration date
July 26, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
July 29, 2022, 5:12 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.



Primary Investigator

University of Chicago

Other Primary Investigator(s)

PI Affiliation
University of Chicago
PI Affiliation
University of Chicago
PI Affiliation
University of Michigan
PI Affiliation
University of Chicago

Additional Trial Information

On going
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
This study examines how being offered the COVID-19 vaccine from a nurse conducting a home visit affects vaccine uptake compared to the standard open offer of vaccination at health facilities. In collaboration with Kisumu County Health Department, this project sends nurses to conduct home visits and inform residents that they are offering the vaccine at a nearby location in the community. Participants are randomly assigned to nurse visits that are unannounced or announced in advance by enumerators conducting a household survey. The study will examine whether there are differences in vaccination rates when information about the visit is provided in advance. The primary outcome of interest is vaccination rate, comparing both vaccination rates between the groups that received a home visit (announced and unannounced) from a nurse, and each nurse visit group to a control group where people can access vaccines at a local health facility.
External Link(s)

Registration Citation

Carney, Kevin et al. 2022. "Door-to-door mobilization of COVID-19 vaccination in Kenya ." AEA RCT Registry. July 29.
Experimental Details


T1) Respondents are told by enumerators at the end of a household survey that a nurse is coming to offer them the COVID-19 vaccine – the nurse visits the household shortly after the end of the survey to offer the vaccine. (Announced)
T2) Respondents are not told that the nurse is coming – the nurse visits the household shortly after the end of the survey to offer the vaccine. (Unannounced)
T3) Respondents are not visited by the nurse. (Control/Status Quo)
T4) Respondents are not surveyed and visited by the nurse without prior announcement. (Nurse only)
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Rates of COVID-19 vaccination. The primary outcome is COVID-19 vaccination rate, which will be measured at different points in time. Any additional jab/dose of the vaccine, including booster shot(s), will be included in the calculation. Rates of vaccination will be measured in the immediate- (day of), short- (1 week), medium- (1 month), and long-term (3 months) from the last day of the intervention. Rates of vaccination for each treatment group will be calculated as the number of vaccines accepted and administered as a share of the total sample size of the treatment group.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
The study will also examine additional outcomes, including: Respondent's stated willingness to get vaccinated; Rate of finding the target respondent at home when the nurse visits; Additional household members’ vaccination behavior; Difference between stated intention to vaccinate and actual acceptance of the vaccine (for T1 & T2).
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
The study will survey 2500 households in Kisumu County in Kenya. An enumerator will conduct a survey to collect information on intentions to obtain a COVID-19 vaccine. At the end of the survey, enumerators will either not announce (T1/Unannounced) or announce (T2/Announced) to survey respondents that a nurse will arrive shortly to provide a COVID-19 vaccination. After the survey, the nurse will arrive for the home visit to offer administering the vaccine to household members at a nearby vaccination site that is within minutes walking distance. The choice to use nurses to mobilize participants to get vaccinated at a nearby site, rather than administer the vaccine door-to-door, was in order to follow government regulations of vaccine transportation.

The study will also compare vaccine uptake in households that receive a nurse visit (T1 & T2) with the status quo policy, where surveyed households are not visited by a nurse but can access the vaccine at a local health facility or community campaign (T3/Control).

There is also a fourth comparison group of households who are not surveyed by enumerators, but are visited by the nurse without prior announcement and offered the vaccine (T4/Nurse Only). The vaccination rate in this group will be compared to T1/unannounced, and if no differences are found, the two groups will be pooled in some analyses.
Experimental Design Details
Randomization Method
In each village, thirty households were randomly selected using an office computer and randomly assigned to a treatment group, which was done in the office by a computer. The sampling procedure preferenced the selection of (i) pregnant women, (ii) people aged 50 years and older, while maintaining gender balance (50% men and 50% women) in each village.
Randomization Unit
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Sample size: planned number of observations
3000 (2500 who are surveyed and allocated to T1-T3; 500 who are not surveyed but visited by a nurse in T4)
Sample size (or number of clusters) by treatment arms
Sample size for T1/Announced: 850
Sample size for T2/Unannounced: 850
Sample size for T3/Control: 800
Sample size for T4/Nurse Only: 500
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
We are powered to detect a 0.0473 difference in proportions in vaccine uptake between T1 and T2, with a sigma of 0.045. We are powered to detect a 0.0418 difference in proportions in vaccine uptake between T1/T2 and T3, with a sigma of 0.04.

Institutional Review Boards (IRBs)

IRB Name
Maseno University Scientific and Ethics Review Committee
IRB Approval Date
IRB Approval Number
IRB Name
University of Chicago
IRB Approval Date
IRB Approval Number


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Data Collection Complete
Data Publication

Data Publication

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Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials