During the COVID-19 pandemic, public health agencies and decision-makers have used social media to disseminate information, encourage changes to behaviour and promote community supports and resources . Their communications have served to educate the public on risks and initiate the widespread adoption of public health measures to 'flatten the curve' . We conducted a content analysis of COVID-19 Tweets by Canadian public health accounts during the first 6 months of the pandemic to explore differences in Tweeting practices by geography and identify opportunities to improve risk communication . We found that Canadian public health accounts in particular geographic settings did not always apply best practices for health communication . Tweeting practices differed considerably between jurisdictions with varying burdens of COVID-19 . Going forward, Tweets authored by public health accounts that promote behaviour change and community-building ought to be utilized whenever risks to health are high to reflect an increase in disease transmission requiring intervention . Our study highlights the need for public health communicators to deliver messaging that is relevant for the levels of risk that their audiences are encountering in a given geographic context.