Persistence of anti-SARS-CoV-2 IgM in convalescent COVID-19 patients

•IgM was tested in convalescent individuals following SARS-CoV-2 infection 1 year previously.•Of survivors, 23.9% were positive for anti-SARS-CoV-2 IgM.•Higher IgM titers were detected in convalescent individuals with severe COVID-19.•IgM testing does not replace PCR testing in detecting acute SARS-CoV-2 infection.•IgM testing should not determine the need to quarantine. Dear Editor, We read with interest the article by Cancella et al. on the...