It is hypothesised that inhaler-mediated corticosteroid use may decrease angiotensin-converting enzyme (ACE2) expression, thus decreasing SARS-CoV-2 cell-entry efficiency.31 This could potentially explain why those hospitalised with SARS-CoV-2 infection were less likely to have asthma, although we did not collect information on corticosteroid use. Here, ACE2 is linked to asthma.