Implementing behavioural science-informed letter interventions to increase COVID-19 vaccination uptake in London residents. A difference-in-difference study in London, United Kingdom
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The accelerated development of vaccines to mitigate COVID-19 was crucial in the response to the 2020 pandemic. The success of vaccination strategies relies upon adequate uptake across the population. In the United Kingdom, COVID-19 vaccination began in December 2020, with population groups invited in priority groups according to age and clinical vulnerability. By February 2021, uptake rates were lower in North West London than the national average. This study aimed to explore whether behaviourally-informed (BI) letters could increase the rate of first vaccine uptake in previously uncontactable residents.
BI letters were designed to invoke a sense of ownership, and highlight the ease of accessing a vaccine. Letters were sent to unvaccinated uncontactable residents in a Central London Borough over a 3-week period. Three neighbouring boroughs in London with similar non-responder data acted as controls. A linear difference in difference (DID) analysis assessed the change in the rate of vaccine uptake across all four boroughs, with percentage point change adjusted for covariates including ethnicity, age, gender and socioeconomic status.
In total, 10,161 residents in Central London were eligible to receive our BI letter. All four boroughs demonstrated an increase in vaccination, with an absolute increase of 4.3 % in the intervention borough. Our linear DID analysis showed a 14.7 % increase in vaccination likelihood in the intervention borough following the intervention on average across all weeks included in the study. Residents with a mixed or multiple ethnic background were less likely to receive a COVID-19 vaccination. Those from a more deprived socioeconomic background demonstrated the largest rate of change.
Our study highlights the effectiveness of traditional communication strategies such as letters in those who are uncontactable by other means. Incorporating behavioural science principles into healthcare communication, such as those designed to evoke a sense of ownership can enhance their effectiveness.
BI letters were designed to invoke a sense of ownership, and highlight the ease of accessing a vaccine. Letters were sent to unvaccinated uncontactable residents in a Central London Borough over a 3-week period. Three neighbouring boroughs in London with similar non-responder data acted as controls. A linear difference in difference (DID) analysis assessed the change in the rate of vaccine uptake across all four boroughs, with percentage point change adjusted for covariates including ethnicity, age, gender and socioeconomic status.
In total, 10,161 residents in Central London were eligible to receive our BI letter. All four boroughs demonstrated an increase in vaccination, with an absolute increase of 4.3 % in the intervention borough. Our linear DID analysis showed a 14.7 % increase in vaccination likelihood in the intervention borough following the intervention on average across all weeks included in the study. Residents with a mixed or multiple ethnic background were less likely to receive a COVID-19 vaccination. Those from a more deprived socioeconomic background demonstrated the largest rate of change.
Our study highlights the effectiveness of traditional communication strategies such as letters in those who are uncontactable by other means. Incorporating behavioural science principles into healthcare communication, such as those designed to evoke a sense of ownership can enhance their effectiveness.
Date Issued
2025-03-07
Date Acceptance
2025-01-21
Citation
Vaccine, 2025, 49
ISSN
0264-410X
Publisher
Elsevier
Journal / Book Title
Vaccine
Volume
49
Copyright Statement
© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/39892113
PII: S0264-410X(25)00078-7
Subjects
Behavioural science
COVID-19 vaccinations
Preventative healthcare
Vaccination uptake
Humans
London
COVID-19
COVID-19 Vaccines
Male
Female
Middle Aged
Vaccination
Adult
Aged
SARS-CoV-2
Young Adult
Adolescent
Vaccination Hesitancy
Publication Status
Published
Coverage Spatial
Netherlands
Article Number
126781
Date Publish Online
2025-01-31