The medical condition Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which primarily targets the epithelial cells, lining the surface of the respiratory passageways and lungs, where it causes viral pneumonia and acute respiratory distress syndrome (ARDS).  Elderly patients, people with asthma, and those with chronic obstructive pulmonary disease (COPD) are especially vulnerable to severe forms of the disease. 

As smoking plays an important part in the development of COPD, questions have been raised whether smokers have a higher risk of infection, as well as a higher risk of developing severe forms of COVID-19.

Does smoking pose a higher risk of infection?

Various studies have tried to ascertain whether smokers are at a higher risk of getting COVID-19.  So far scientists have not found signs of a cause-and-effect relationship between smoking and increased risk of getting COVID-19.

Does smoking pose a higher risk of severity of infection?

While smoking does not seem to pose a higher risk of contracting the disease, it seems play a significant role in the severity of the disease.

Numerous studies and statistical analysis of increasingly available data have linked active smoking, and a history of smoking, to a significant higher risk of getting a more severe form of COVID-19, with severe cases described as critical, the need for ICU, being on ventilators, and non-survivors.  Smoking often has an impact on the same organs that are affected by COVID-19, such as the lungs, heart, and the vascular system.  Smokers that already have serious heart and lung problems are more vulnerable, when infected by the virus.

Many smokers already have compromised immune systems, making the body less successful at fighting disease.  The effects of tobacco smoke on the body can lead to greater susceptibility to infections such as pneumonia and influenza, and to having lower levels of protective antioxidants, such as vitamin C, in the blood.  Cigarette smoke contains more than 7,000 chemical compounds and many of them can interfere with the immune system.

When exposed to the COVID-19 virus, it easily enters airways and lungs, with a large surface area of epithelial cells, where the virus primarily targets and binds to specific receptors on the epithelial cells, which are the cells lining the surfaces of the body such as the lungs, the blood stream, and the gut.  Epithelial cells are the first cell type to encounter external stimuli, including viruses such as COVID-19.  In people with healthy, uncompromised immune systems, incoming viruses might normally be destroyed by the protective epithelial cells in the lungs.

The coronavirus enters human cells by attaching to a surface receptor protein called angiotensin-converting enzyme 2 (ACE2).  Some of the research into the effects of smoking on COVID-19 have indicated that smoking can produce higher levels of ACE2 receptors on the inner epithelial cells of the lungs, which makes it easier for viral invasions such as COVID-19 to latch onto the extra ACE2 receptors.  This can allow the virus to overwhelm and destroy epithelial cells in the lungs and then multiply quickly inside the patient.

Lung damage seen in COVID-19 patients.

Some patients – who have recovered from COVID-19 – have reported persistent lung-related symptoms, such as difficulty breathing and other lasting symptoms.  These people are referred to as “long-COVID” patients.

The damage caused by COVID-19 to the lungs was highlighted in post-mortem samples from people who have died from COVID-19.  All cases showed vast destruction of lung tissue and lung anatomy, such as lung thrombosis (blood clotting) and endothelial dysfunction.  These findings of lung damage may explain the incidences of “long-COVID” in some patients.


COVID-19 is a highly infectious disease that primarily attacks the lungs.  Smoking impairs lung function, which makes it harder for the body to fight off coronaviruses and other diseases, says the World Health Organization (WHO).

Doctors and medical researchers have found that people are finding it hard to quit smoking during the stress and uncertainty caused by the current pandemic.  The recommended way to quit is to not stop smoking abruptly, but to taper off smoking over time.  It helps to have a tapering schedule on a calendar, working towards a quit date.  A relapse now and then should not discourage people from following the tapering schedule.


Tobacco use and COVID-19.  Published 11 May 2020.  Statement by the World Health Organization.  (

Smoking and COVID-19.  Published 30 June 2020.  World Health Organization.  (

Cigarette smoking and COVID-19: a complex interaction.  Published 1 August 2020 by the American Thoracic Society.  American Journal of Respiratory and Critical Care Medicine.  National Center for Biotechnology Information.  US National Library for Medicine. National Institutes of Health.  (

Does smoking increase the risk of severe COVID-19 illness?  Published 1 September 2020.  Cedars Sinai (non-profit hospital in Los Angeles.)  (

Exploring the effects of smoking tobacco on COVID-19 risk.  Published 14 October 2020.  News Medical.  (

Smoking – effects on your body.  Published online and updated February 2019.  Better Health Channel.  Victoria State Government, Australia.  (

Impacts of cigarette smoke on immune responsiveness: up and down or upside down?  Published 3 January 2017.  Oncotarget.  (Open Access Impact Journal.)  National Center for Biotechnology Information.  US National Library for Medicine. National Institutes of Health.  (


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