RESUMEN
Formative research is an important component of health communication campaign development. Rapid message testing approaches are useful for testing new messaging quickly and efficiently during public health emergencies, such as COVID-19, when guidance and recommendations are rapidly changing. Wiki surveys simultaneously collect quantitative message testing data and qualitative feedback on potential social media campaign messages. Philly CEAL used wiki surveys to test messages about COVID-19 vaccinations for dissemination on social media. A cross-sectional survey of Philadelphia residents (N = 199) was conducted between January and March 2023. Wiki surveys were used to assess the perceived effectiveness of messages promoting the updated COVID-19 booster and child vaccination. In each wiki survey, participants were presented with two messages and asked to select the one that they perceived as most effective. Participants could alternatively select "can't decide" or submit their own message. A score estimating the probability of selection was calculated for each message. Participant-generated messages were routinely reviewed and incorporated into the message pool. Participants cast a total of 32,281 votes on messages seeded by the research team (n = 20) and participants (n = 43). The highest scoring messages were those that were generated by participants and spoke to getting your child vaccinated to protect them against serious illness and getting the booster to protect your health and that of your community. These messages were incorporated into social media posts disseminated by Philly CEAL's social media accounts. Wiki surveys are a feasible and efficient method of rapid message testing for social media campaigns.