ACE2 and COVID-19: As the COVID-19 pandemic spread globally, we observed some cases of IIM flare-ups in previously healthy individuals or relapses in patients considered to be in remission or with low disease activity after COVID-19 or SARS-CoV-2 vaccination [15–24], which may be related to the expression of angiotensin-converting enzyme 2, the SARS-CoV2 receptor in skeletal muscle [25].