Smokers should quit to reduce their risks from COVID-19, according to the International Union Against Tuberculosis and Lung Disease (IUATLD).

Tobacco companies should immediately stop producing, marketing and selling tobacco to fight the pandemic, the group’s director, Gan Quan, said in a statement.

“The data are still emerging, but evidence already demonstrates the negative impact of tobacco use on lung health and its causal association with a large range of respiratory diseases,” the IUATLD statement said. “Smoking weakens the immune system and its responsiveness to infections, making smokers more vulnerable to infectious diseases. This includes COVID-19.”

The statement noted a study of more than 1,000 COVID-19 patients, published in the New England Journal of Medicine, found past and present smokers fared worse than non-smokers, Reuters reports. Smokers comprised more than 25% of those who needed mechanical ventilation, were admitted to an ICU or died.