Increasing vaccination: reminders work, and a behaviourally-informed chatbot works better
| ISRCTN | ISRCTN13725439 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN13725439 |
| Secondary identifying numbers | AEARCTR-0009758 |
- Submission date
- 03/06/2024
- Registration date
- 07/06/2024
- Last edited
- 17/10/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Infections and Infestations
Plain English summary of protocol
Background and study aims
In this study, a new chatbot will be designed and tested to understand whether two-way interactive messaging incorporating behaviourally-informed functionalities could perform better than one-way message reminders. A large-scale pre-registered randomly allocated and controlled trial will be performed with 249,705 participants in Chaco, Argentina, measuring vaccinations using Ministry of Health (MoH) records. Randomisation will be conducted at the individual level, with one-third of the sample (83,235 participants) assigned to receive the WhatsApp chatbot, another third to receive a single one-way WhatsApp message encouraging them to get the next dose of the COVID-19 vaccine, and the final third of the sample to receive no message (the control group).
Who can participate?
Adults aged 18 years old and over who had received at least one dose of the COVID-19 vaccine
What does the study involve?
Participants for the trial will be selected from one of three phone databases owned by the MoH. The study is a three-arm trial using data from MoH records to test whether a chatbot can increase vaccination more than a one-way message reminder or no message. Participants in the WhatsApp chatbot group received interactive messages incorporating several functionalities based on insights from behavioural science. First, they will receive individual-level personalised information on their eligibility based on the government’s vaccination database. Second, they could use a locator tool to find their nearest vaccination centres based on their postcode or by using WhatsApp’s ‘Share Location’ functionality. Third, they will be prompted to make a plan for when and where they will get vaccinated. Fourth, they will receive a reminder message the day before their chosen date, and fifth, they will be provided a link with Google Maps directions on how to get to their chosen centre. In each case, users can reply to the chatbot’s messages by choosing an answer from a set menu of options. Participants in the one-way message group receive a single WhatsApp message encouraging them to get the next dose of the COVID-19 vaccine. Participants in the control group will not receive any messages.
What are the possible benefits and risks of participating?
Potential participation benefits include receiving personalized information regarding COVID-19 vaccination eligibility, vaccination centres, and reminder-setting, which aims to promote vaccination outcomes. No anticipated major risks associated with participation are expected. The risk that participation may yield a lower vaccination outcome will be minimised by developing the messages based on qualitative research with the target population in Chaco, Argentina, as well as input from experts and consultations with the Government of Argentina’s Unidad de Ciencias del Comportamiento y Políticas Pública.
Where is the study run from?
Chaco, Argentina
When is the study starting and how long is it expected to run for?
September 2021 to December 2022
Who is funding the study?
1. Vaccine Confidence Fund
2. Inter-American Development Bank
Who is the main contact?
1. Dan Brown, dan.brown@cantab.net
2. Adelaida Barrera, adelaidabarrera@gmail.com
Contact information
Scientific, Principal Investigator
None provided
London
None provided
United Kingdom
| Phone | None provided |
|---|---|
| dan.brown@cantab.net |
Public, Principal Investigator
None provided
London
None provided
United Kingdom
| Phone | None provided |
|---|---|
| adelaida.barrera@bi.team |
Study information
| Study design | Naturalistic randomized controlled trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Community, Medical and other records |
| Study type | Efficacy |
| Participant information sheet | No participant information sheet available |
| Scientific title | Original Title for Pre-Registration: Implementation of a Chatbot Based on Behavioral Strategies to Promote Continuity of COVID-19 Vaccination: A Randomized Controlled Trial. Current Title: Increasing vaccination: reminders work, a behaviourally-informed chatbot works better. |
| Study objectives | Participants who receive personalized WhatsApp chatbot messages informed by behavioral principles will exhibit a higher rate of COVID-19 vaccination during the 4-week period following the intervention compared to each of the two comparison groups (one group receives a one-way message reminder, and the other receives no message). |
| Ethics approval(s) |
Approved 29/06/2022, Comité de Bioética, Hospital Universitario Fundación Favaloro (Bioethics committee, Favaloro Foundation University Hospital) (Av. Belgrano 1746, Buenos Aires, C1095, Argentina; +54 11 4378-1229; comitedebioetica@ffavaloro.org), ref: CBE Acta 121 29/06/2022 |
| Health condition(s) or problem(s) studied | Promotion of COVID-19 vaccination in the general population |
| Intervention | Participants in the treatment group will receive personalised WhatsApp chatbot messages informing them they are eligible for the next dose with a motivational message leveraging loss aversion (“don’t lose your immunity”), sharing practical information on when and where to get vaccinated, providing planning prompts, and enabling them to set reminders to get their next dose of the COVID-19 vaccine on a convenient date. Participants in the one-way message control group will receive a single WhatsApp message (i.e., a message they cannot interact with) informing them they are eligible for the next dose and with a motivational message leveraging loss aversion (“don’t lose your immunity”). This single message is identical to the first communication of the treatment chatbot. Finally, participants in the control group do not receive a message. Randomisation will be conducted at the individual level, with one-third of the sample (83,235 participants) assigned to receive the WhatsApp chatbot, another third to receive a single one-way WhatsApp message encouraging them to get the next dose of the COVID-19 vaccine, and the final third of the sample to receive no message (the control group). The unit of randomisation is the individual as identified by their national ID number. Using a random number generator, participants are assigned to one of three groups (chatbot group, one-way message reminder group, control group), and stratified by the number of COVID-19 vaccine doses already received by the individual (1, 2, 3 or 4). |
| Intervention type | Behavioural |
| Primary outcome measure | Next dose vaccination rate, indicating whether the individual received the next dose for which they are eligible, measured using administrative data provided by the Ministry of Health which includes information on the date of vaccination within four weeks of entering the trial |
| Secondary outcome measures | There are no secondary outcome measures |
| Overall study start date | 23/09/2021 |
| Completion date | 31/12/2022 |
Eligibility
| Participant type(s) | Population |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 241, 435 individuals |
| Total final enrolment | 249705 |
| Key inclusion criteria | Individuals from Chaco province, Argentina, will be included in the trial if: 1. They are aged 18 years old and over 2. Have received the first COVID-19 vaccination dose 3. Are eligible to receive their next COVID-19 dose (i.e., 2nd, 3rd, 4th, or 5th dose of the COVID-19 vaccination) 4. Have a valid mobile number registered within the database 5. Their mobile number is registered with WhatsApp 6. The mobile number is unique to one individual within the database |
| Key exclusion criteria | Not meeting the participant inclusion criteria |
| Date of first enrolment | 08/09/2022 |
| Date of final enrolment | 21/09/2022 |
Locations
Countries of recruitment
- Argentina
Study participating centre
3500
Argentina
Sponsor information
Research organisation
58 Victoria Embankment
London
EC4Y 0DS
England
United Kingdom
| Phone | None provided |
|---|---|
| dpo@bi.team | |
| Website | https://www.bi.team/ |
"ROR" |
https://ror.org/03mk5b468 |
Funders
Funder type
Charity
Private sector organisation / Other non-profit organizations
- Alternative name(s)
- VCF
- Location
- United States of America
Private sector organisation / International organizations
- Alternative name(s)
- Banco Interamericano de Desarrollo, Banco Interamericano de Desenvolvimento, Banque Interaméricaine de Développement, IADB, BID, IDB
- Location
- United States of America
Results and Publications
| Intention to publish date | 31/12/2024 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Stored in publicly available repository |
| Publication and dissemination plan | Planned publication in a peer-reviewed journal |
| IPD sharing plan | The anonymity-preserving data used in the analysis are publicly available in the Dryad data repository at the following link: https://datadryad.org/stash/share/HPMMIkG8ltPniOJJChLa6ci81SaDKXK24I68g8njXCk. Note: No accession code is required. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol file | 11/07/2022 | 17/10/2024 | No | No |
Additional files
Editorial Notes
17/10/2024: Protocol (not peer-reviewed) uploaded.
03/06/2024: Study's existence confirmed by the Bioethics committee, Favaloro Foundation University Hospital.
