Nationwide demonstration of improved COVID-19 vaccination uptake through behavioural reminders.

Here we report the results of two nationwide randomized controlled trials. By refining behavioural-science-informed text messages notifying patients of their vaccine eligibility, we observed improvements in vaccination rates. The randomized controlled trials involved adults aged 40-44 years (n = 1,825,937) and 24-29 years (n = 2,174,064) in England. Messages emphasizing 'Top of queue' status led to small, but policy-relevant, increases in vaccination rates in both the 40-44 age group (odds ratio 1.02, 95% confidence interval 1.01-1.03) and the 24-29 age group (odds ratio 1.02, 95% confidence interval 1.01-1.04). Consequently, the 'Top of queue' message was nationally rolled out to other age groups. These findings demonstrate the potential of 'queue' framing in relevant contexts and the value of rigorous testing of public health messaging.