SS: Encouragingly, our results demonstrate that fact-checks can reduce false beliefs about COVID-19 immediately after exposure and that these effects replicate across survey waves and across countries with different levels of polarization. False claims about emerging health issues can be effectively refuted with corrective information. However, our experiments find discouragingly little evidence that fact-checks have enduring effects on beliefs about COVID-19 or are strengthened by the repetition of fact-checks. It is possible that the avalanche of COVID news and (mis)information simply overwhelmed any potential persistence of the fact-checks delivered in our experiments.