Positive attribute framing increases COVID-19 booster vaccine intention for unfamiliar vaccines

Positive framing has been proposed as a potential intervention to increase COVID-19 vaccination intentions. However, most available research has examined fictitious or unfamiliar treatments. This pre-registered study compared positively and negatively attribute-framed side effect information for real COVID-19 booster vaccines (AstraZeneca, Pfizer, Moderna) and measured booster intentions pre- and post-intervention in 1,222 UK-based participants. As hypothesised, vaccine familiarity significantly modulated the effect of framing. While positive framing was effective for the least familiar vaccine (i.e., Moderna), standard negative framing appeared to increase intentions for familiar vaccines (AstraZeneca/Pfizer), particularly among those with low baseline intentions. These findings provide important new evidence that positive framing could improve vaccine uptake globally when switches or new developments require individuals to receive less familiar vaccines – as is currently the case for millions of booster vaccines across the world. Positive framing of familiar vaccines, however, should be treated with caution.