A behaviourally informed chatbot increases vaccination rates in Argentina more than a one-way reminder.

Maintaining COVID-19 vaccine demand was key to ending the global health emergency. To help do this, many governments used chatbots that provided personalized information guiding people on where, when and how to get vaccinated. We designed and tested a WhatsApp chatbot to understand whether two-way interactive messaging incorporating behaviourally informed functionalities could perform better than one-way message reminders.