Introduction: Amid the COVID-19 pandemic, many rumours have emerged. Given prior research linking rumour exposure to mental well-being, we conducted a nationwide survey to document the base rate of rumour exposure and factors associated with rumour vulnerability. Methods: Between March and July 2020, 1,237 participants were surveyed on 5 widely disseminated COVID-19 rumours (drinking water frequently could be preventive, eating garlic could be preventive, the outbreak arose because of bat soup consumption, the virus was created in an American lab, and the virus was created in a Chinese lab). For each rumour, participants reported whether they had heard, shared or believed each rumour. Results: Although most participants had been exposed to COVID-19 rumours, few shared or believed these. Sharing behaviours sometimes occurred in the absence of belief; however, education emerged as a protective factor for both sharing and belief. Conclusion: Our results suggest that campaigns targeting skills associated with higher education (e.g. epistemology) may prove more effective than counter-rumour messages.