ABSTRACT
At present, COVID-19 continues to spread around the world. People are generally susceptible to SARS-CoV-2. The elderly, serious chronic underlying diseases, high-risk pregnancy, severe obesity and other factors are related to the progression of COVID-19 to severe, critical illness, and even death caused by deterioration of the disease. The relationship between smoking and COVID-19 seems to be controversial. The smoking rate of hospitalized COVID-19 patients is significantly lower than that of the general population. Therefore, smoking can reduce COVID-19 infection and protect the respiratory tract. Subsequently, many scholars have carried out research on this, thinking that this is a wrong and misleading conclusion. According to WHO, smoking is significantly related to the severity of COVID-19, which is one of the important risk factors for the deterioration and poor prognosis of COVID-19. This article reviews the mechanism of smoking increasing the risk of COVID-19 infection.