In Myanmar, Facebook has been used to circulate authoritative information about covid-19, with sources coming from Myanmar’s Ministry of Health, the Ministry of Information, and mainstream, credible media. However, hundreds of large Facebook groups – with roughly 24 million members – are also powerful vehicles for the spread of health misinformation throughout the country. We found a set of Facebook pages and groups that quickly amplified the reach of discriminatory content, with user engagement growing rapidly in a few hours. Polarisation is expected to rise ahead of the November elections and we recommend that Facebook and their fact-checking partners intensify their efforts and work with election stakeholders to create more awareness about credible information about the polls and counter health misinformation, which has the potential to impact voter turnout.