However, in a recent analysis of transcriptomic data, the presence of ACE2 in the pancreatic islet β cells were not conclusive: TMPRSS2 was not co-expressed with ACE2 in these cells, which is a necessary co-factor to facilitate SARS-CoV-2 cellular entry (Coate et al., 2020; Hoffmann et al., 2020; Ozono et al., 2021); however, with SARS, diabetes was in some cases was shown to persist for 3 years after infection, indicating potential damage to islet β cells (Yang et al., 2010). This evidence concerns the gene ACE2 and diabetes mellitus.