As if smoking per se weren’t bad enough, now, it turns out that smoking significantly worsens COVID-19, according to a new analysis by UC San Francisco of the association between smoking and progression of the infectious disease.

In a meta-analysis of studies that included 11,590 COVID patients, researchers found that among people with the virus, the risk of disease progression in those who currently smoke or previously smoked was nearly double that of non-smokers. They also found that when the disease worsens, current or former smokers had more acute or critical conditions or death. Overall, smoking was associated with almost a doubling of the risk of disease progressing.