Smokers and former smokers, including e-cigarette users, have a significantly greater risk of developing severe cases of COVID-19 and dying from the illness than their non-smoking counterparts, according to a new study from the University of California, San Francisco.

“Smoking is associated with substantially higher risk of COVID-19 progression,” Stanton Glantz, a professor of medicine at the UCSF Center for Tobacco Control Research and Education, said in a statement.

The meta-analysis, or study of studies, looked at 19 peer-reviewed papers from China, South Korea and the United States. It found 30% of smokers developed more severe forms of Covid-19 compared to 17.6% of non-smokers.

“Smoking and e-cigarette use increase the risk and severity of pulmonary infections because of damage to upper airways and a decrease in pulmonary immune function in general, although these effects have not yet been studied for SARS-COV-2, the virus that causes COVID-19,” they wrote. “Smokers have a known higher risk of infection and mortality from MERS-COV, a viral respiratory illness caused by a different coronavirus.”

The analysis likely underestimated how smoking affects the risk of contracting the coronavirus in the general population, the authors said, because the studies the analysis is based on were only focused on those who had already developed Covid-19.

But the authors urged health officials to add smoking cessation for both tobacco and e-cigarette products to the list of steps needed to curb the pandemic, and are advocating for more data collection on smokers and e-cigarette users to see if they’re at greater risk of contracting the disease. (CNN)