The statistics seem robust in all countries: if you are a smoker, you are less likely to be admitted to hospital because of COVID-19.
Official French data replicates the picture in China, Germany and the United States: a remarkably low rate of smokers are hospitalized with coronavirus compared to the prevalence of smoking (France, 23%). But statistics are one thing and the science behind possible explanations for this correlation is another .
Simple correlation?
The data from the United States according to the CDC is also very shocking in this regard . Among 7,162 coronavirus patients with medical records, 6,901 were never smokers (96.3%), 165 ex-smokers (2.3%), and only 96 smokers (1.3%):
Nicotine would decrease the angiotensin converting enzyme II (ACE-2), according to this study . A team of Chinese researchers has discovered how COVID-19 uses the protein ‘ACE2’ to enter human cells.
However, contrary to the previous theory, a study from China finds an increased expression of ACE2 in smokers: "because people with chronic obstructive pulmonary disease (COPD) have an increased risk of severe COVID, we determined whether the expression of ACE2 in the lower airways was related to COPD and smoking. "
The ACE-2 molecule, found on the surface of lung cells, is the "entry point" that allows coronavirus to enter lung cells and cause infection. The smoke itself causes the lungs to increase the expression of mucus-secreting cells high in ACE2. This finding , published in the journal Science , about the possibility of developing antibodies to stop the infection .
And a recent meta-analysis published in the medical journal Tobacco Induced Diseases , investigates how Covid-19 affects those who are smokers and corroborates that smoking would be related to a negative progression and adverse results in people with Covid-19.
Elucidating this is important, because if there is a protective effect of nicotine, could some analog or derivative be developed that can produce the same effect without the harm of nicotine?