Vaccine hesitancy is multifactorial and difficult to address. In this randomized controlled trial, Freeman et al. recruited over 18,000 adults in the UK and assessed their willingness to be vaccinated against COVID-19. Around 10% of participants were strongly hesitant, questioning the safety and benefit of vaccination. Participants were randomized to 10 different information types, ranging from messaging highlighting the public benefit to addressing concerns about the speed of development. The most effective message for reducing vaccine hesitancy was explaining the personal benefits of vaccination, including prevention of serious illness and long-term health problems, although the effect was relatively small. Of note, the overall willingness of people to get vaccinated had increased substantially since a previous similar study that was conducted in October 2020 compared to the current study, which was conducted in February 2021.