Premature closure occurs when clinicians accept a diagnosis before it has been confirmed and alternative diagnoses have been explored and can lead to missed diagnosis. In this study, participants (including both health care professionals and community members) were provided one of five scenarios describing a hypothetical patient with symptoms suggestive of COVID-19 in the presence or absence alternative diagnosis (e.g., COVID-19 symptoms and the presence or absence of a positive flu test). Findings suggest that bias can lead individual to overlook the likelihood of COVID-19 when an alternative diagnosis is present.