Background: Vaccination is an important strategy for overcoming public health crises. Considerable studies have analyzed strategies to promote people's willingness to vaccinate, but few have explored effective strategies based on the stage of vaccine launch. This study considered the framing effect theory to explore whether egoism, altruism and loss frames can boost vaccination willingness when people feel the vaccine is effective in the late stage of vaccine launch.
Methods: This study designed a scenario experiment consisting of three experimental groups (egoism, altruism and loss frames) and one control group (non-framed). Participants (N = 1085) from China were randomly assigned to any of the four groups. Vaccination willingness, perceived vaccine effectiveness and control variables included perceived susceptibility, perceived severity, worry about the side effects of vaccination and socio-demographics were collected.
Results: Perceived vaccine effectiveness and message frames can increase people's willingness to be vaccinated. Message frames can amplify the positive impact of perceived effectiveness on vaccination willingness. Moreover, loss-framed messages had a stronger amplification effect than egoistic- and altruistic-framed messages.
Conclusions: Governments and other health authorities should prioritize the loss-framed approach when constructing vaccination slogans to maximize vaccination willingness when vaccines are considered effective at the late implementation stage of the vaccine strategy.