Generate an explanation for the given claim using the provided supporting material from the paragraph. Please consider the following points while generating an output. 1) The claim will always have supporting proof in the paragraph, and the paragraph will have a clear point of view supporting the claim. 2) There can be instances where direct correlation to the claim is not available. Make use of the sentences in the paragraph to provide a corresponding output supporting the claim. 3) The explanation should be at least one and at most twelve sentences long.

Paragraph: "The best thing the tobacco industry can do to fight COVID-19 is to immediately stop producing, marketing and selling tobacco," Gan Quan, a public health specialist and a director at the International Union Against Tuberculosis and Lung Disease, said in a statement. The group, which links international respiratory and lung specialists, officials and health agencies, said it is "deeply concerned" about COVID-19's impact on the world's 1.3 billion smokers, in particular those in poorer countries whose health systems are already overburdened. Smoking is known to weaken the immune system, making it less able to respond effectively to infections. Smokers may also already have lung disease or reduced lung capacity which would greatly increase the risk of serious illness. Quan said governments around the world had a "moral imperative" to advise smokers to stop. "This is the absolute best time to quit smoking," Quan said. The Union's statement cited emerging evidence from preliminary studies of COVID-19 patients in China and elsewhere that suggest smokers infected with the new coronavirus become more severely ill and suffer more serious complications such as breathing difficulties. It said a study of more than 1,000 COVID-19 patients published in the New England Journal of Medicinein February found that smokers - both past and present - fared poorly, with smokers comprising more than 25% of those that needed mechanical ventilation, admission to an intensive care unit, or who died. The World Health Organization and the European Centre for Disease Control and Prevention have also warned that smoking can expose people to serious complications from COVID-19. Claim: Experts urge smokers and tobacco firms to quit for COVID-19.
Health experts on Monday urged smokers to quit and cigarette companies to stop producing and selling tobacco products to help reduce the risks from COVID-19.