[cramey]

All substance abuse, including smoking, is a comorbidity[1]. While it's hard to find exact statistics, the US Department of Health and Social Services estimates that 50% of non-elderly Americans have a pre-existing condition[2]. Those conditions don't necessarily represent a comorbidity, but a nasty systemic infection like Covid-19 leaves little space for non-overlap.

1: https://en.wikipedia.org/wiki/Comorbidity

2: https://www.cms.gov/CCIIO/Resources/Forms-Reports-and-Other-...