Does smoking put you at greater risk of the coronavirus?

Does smoking put you at greater risk of the coronavirus? Scientists discover critically ill patients are more likely to be smokers – but one Chinese study finds they are LESS likely to get the killer infection in the first place

  • Chinese experts found a quarter of critically ill infected patients were smokers
  • In comparison, only 11 per cent of patients with mild symptoms were smokers
  • Another study in Wuhan – where the pandemic began – made the same finding
  • But one by another team found smokers were less likely to catch the deadly virus
  • In another twist, it also found smokers were more likely to suffer complications
  • Coronavirus symptoms: what are they and should you see a doctor?

Smokers face a greater risk of suffering severe complications from the coronavirus, according to research.

Chinese academics found a quarter of infected patients who needed life support or died were smokers. 

In contrast, only 11 per cent of patients with mild symptoms such as a cough and a fever were smokers.

Another study by experts in Wuhan – where the pandemic began – also discovered smokers were more likely to see their disease progress.

But one by another team from the Chinese city were mystified after finding smokers were less likely to catch the deadly virus in the first place. In another twist, it also found smokers were more likely to suffer severe complications.

The EU health regulator today ruled smoking can make people more susceptible to serious complications from a coronavirus infection.

But in the same breath, the body admitted the data was still scarce. Doctors across the world have echoed the concern and called for further trials.  

One group of experts, who trawled through evidence, admitted the data is mostly based on assumptions and called for further trials to clarify the danger.

Smoking – a killer habit known to cause cancer – damages lung health and raises the risk of other respiratory infections, such as the flu. 

Chinese academics found a quarter of infected patients who needed life support or died were smokers. In contrast, only 11 per cent of patients with mild symptoms such as a cough and a fever were smokers

Researchers at the Zhongnan Hospital of Wuhan University made the conclusion that only 1.4 per cent of 140 hospitalised patients were smokers. 

Ya-dong Gao and colleagues wrote in the journal Allergy: ‘Interestingly, there were only two current smokers and seven past smokers.’

Of the nine patients classed as smokers, three had non-severe symptoms. The other six were classed as having severe symptoms. 

Writing in the journal, the researchers added: ‘The relationship between smoking and coronavirus infection is not clear.

‘The exact underlying causes of the lower incidence of COVID‐19 in current smokers are still unknown.’

And they admitted: ‘The outcome of SARS‐CoV‐2 infection in smokers may be more severe.’

The study also claimed asthma and chronic obstructive pulmonary disorder (COPD) are not risk factors for catching the infection – contrary to NHS advice. 


One major study, published in the prestigious New England Journal of Medicine, warned that smokers are at higher risk of severe COVID-19.

Researchers supported by the National Health Commission of China looked at more than 1,000 patients diagnosed with the coronavirus.

The scientists found, of the 913 patients with symptoms classed as non-severe, only 11.8 per cent were current smokers. 

However, 16.9 per cent of the 172 COVID-19 patients with severe symptoms were smokers, according to the analysis.

Furthermore, 25.5 per cent of the patients who were needed mechanical ventilation, were admitted to intensive care or died were smokers.










The figure supplied above is based on the NEJM data for the number of patients who needed mechanical ventilation, were admitted to intensive care or died.

Results also showed that hypertension was the most common comorbidity, with 30 per cent of patients having high blood pressure. 

Respiratory doctors at The Central Hospital of Wuhan carried out another study that found smokers were more likely to see their disease progress.

They analysed 78 patients who already had pneumonia caused by COVID-19. All of them were tracked for two weeks.

The experts, led by Wei Liu, found those who use use tobacco are ’14 times as likely to have COVID-19 progression’.

Patients who had high levels of C-reactive protein – a tell-tale sign of inflammation – were 10 times more likely to see their disease progress.

The results, which warned that a history of smoking raised the risk to patients, were published in the Chinese Medical Journal. 

Another study, published in the New England Journal of Medicine, came to a similar conclusion.

Researchers supported by the National Health Commission of China looked at more than 1,000 patients diagnosed with COVID-19.

They found of the patients with symptoms classed as non-severe, only 11.8 per cent were current smokers. 

However, 16.9 per cent of COVID-19 patients with severe symptoms were smokers, according to the analysis.

Furthermore, 25.5 per cent of the patients who were needed mechanical ventilation, were admitted to intensive care or died were smokers.

However, fewer than 15 per cent of the patients involved in the study were smokers – a figure that clashes with China’s smoking rate.

The World Health Organization says 300million people in China smoke – roughly a fifth of the country’s total population and a third of the world’s total. 

Data from a national survey conducted by China in 2015 found up to 60 per cent of men between the ages of 45 and 64 smoke.

British researchers were clueless as to why the NEJM study had such low rates of smokers, especially given 28 per cent of patients were between 50 and 64 and around 60 per cent were men.

One reason they suggested was that it could be down to the demographic of the patients analysed – 43 per cent lived in Wuhan.

It comes as the EU health regulator today warned smoking can make people more susceptible to serious complications from a coronavirus infection.

The European Centre for Disease Control and Prevention (ECDC) included smokers among those potentially most vulnerable to COVID-19. 

However, the body – which cited several different scientific studies – admitted the available data is still limited.

Professor Taylor Hays, from the Mayo Clinic in Rochester, Minnesota, also spoke of a lack of data on COVID-19 in smokers, or vapers.

However, he told Forbes: ‘We do know from reports from China, smokers seem to be over-represented in groups of people who have severe or critical COVID-19,.  

‘These observations about more severe illness in smokers vs people who have never smoked seems to parallel what is seen in respiratory viruses.

‘We know that inhalation of combustible tobacco of any sort seems to be associated with more severe disease from respiratory viruses.’

In a piece published in the journal Tobacco Induced Diseases, other researchers said further research is needed to confirm the link.

The pair wrote: ‘Smoking, to date, has been assumed to be possibly associated with adverse disease prognosis.

‘Evidence has highlighted the negative impact of tobacco use on lung health and its causal association with a plethora of respiratory diseases.’

The two scientists – one from Greece and the other from Harvard – added: ‘Smoking is most likely associated with… adverse outcomes of COVID-19.’  

The ECDC report also said smoking was linked with higher levels of an enzyme in the lungs called ACE2 – thought to raise the risk of severe cases of COVID-19.

Greek researchers found the coronavirus sticks to cells and attacks them by latching onto ACE2. The results were published in The Lancet Respiratory Medicine.

Drugs given to millions of patients with high blood pressure and diabetes can raise the amount of ACE2 they have on their cells, the experts warned.    


What is the coronavirus? 

A coronavirus is a type of virus which can cause illness in animals and people. Viruses break into cells inside their host and use them to reproduce itself and disrupt the body’s normal functions. Coronaviruses are named after the Latin word ‘corona’, which means crown, because they are encased by a spiked shell which resembles a royal crown.

The coronavirus from Wuhan is one which has never been seen before this outbreak. It has been named SARS-CoV-2 by the International Committee on Taxonomy of Viruses. The name stands for Severe Acute Respiratory Syndrome coronavirus 2.

Experts say the bug, which has killed around one in 50 patients since the outbreak began in December, is a ‘sister’ of the SARS illness which hit China in 2002, so has been named after it.

The disease that the virus causes has been named COVID-19, which stands for coronavirus disease 2019.

Dr Helena Maier, from the Pirbright Institute, said: ‘Coronaviruses are a family of viruses that infect a wide range of different species including humans, cattle, pigs, chickens, dogs, cats and wild animals. 

‘Until this new coronavirus was identified, there were only six different coronaviruses known to infect humans. Four of these cause a mild common cold-type illness, but since 2002 there has been the emergence of two new coronaviruses that can infect humans and result in more severe disease (Severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses). 

‘Coronaviruses are known to be able to occasionally jump from one species to another and that is what happened in the case of SARS, MERS and the new coronavirus. The animal origin of the new coronavirus is not yet known.’ 

The first human cases were publicly reported from the Chinese city of Wuhan, where approximately 11million people live, after medics first started publicly reporting infections on December 31.

By January 8, 59 suspected cases had been reported and seven people were in critical condition. Tests were developed for the new virus and recorded cases started to surge.

The first person died that week and, by January 16, two were dead and 41 cases were confirmed. The next day, scientists predicted that 1,700 people had become infected, possibly up to 7,000. 

Where does the virus come from?

According to scientists, the virus almost certainly came from bats. Coronaviruses in general tend to originate in animals – the similar SARS and MERS viruses are believed to have originated in civet cats and camels, respectively.

The first cases of COVID-19 came from people visiting or working in a live animal market in Wuhan, which has since been closed down for investigation.

Although the market is officially a seafood market, other dead and living animals were being sold there, including wolf cubs, salamanders, snakes, peacocks, porcupines and camel meat. 

A study by the Wuhan Institute of Virology, published in February 2020 in the scientific journal Nature, found that the genetic make-up virus samples found in patients in China is 96 per cent identical to a coronavirus they found in bats.

However, there were not many bats at the market so scientists say it was likely there was an animal which acted as a middle-man, contracting it from a bat before then transmitting it to a human. It has not yet been confirmed what type of animal this was.

Dr Michael Skinner, a virologist at Imperial College London, was not involved with the research but said: ‘The discovery definitely places the origin of nCoV in bats in China.

‘We still do not know whether another species served as an intermediate host to amplify the virus, and possibly even to bring it to the market, nor what species that host might have been.’  

So far the fatalities are quite low. Why are health experts so worried about it? 

Experts say the international community is concerned about the virus because so little is known about it and it appears to be spreading quickly.

It is similar to SARS, which infected 8,000 people and killed nearly 800 in an outbreak in Asia in 2003, in that it is a type of coronavirus which infects humans’ lungs. It is less deadly than SARS, however, which killed around one in 10 people, compared to approximately one in 50 for COVID-19.

Another reason for concern is that nobody has any immunity to the virus because they’ve never encountered it before. This means it may be able to cause more damage than viruses we come across often, like the flu or common cold.

Speaking at a briefing in January, Oxford University professor, Dr Peter Horby, said: ‘Novel viruses can spread much faster through the population than viruses which circulate all the time because we have no immunity to them.

‘Most seasonal flu viruses have a case fatality rate of less than one in 1,000 people. Here we’re talking about a virus where we don’t understand fully the severity spectrum but it’s possible the case fatality rate could be as high as two per cent.’

If the death rate is truly two per cent, that means two out of every 100 patients who get it will die. 

‘My feeling is it’s lower,’ Dr Horby added. ‘We’re probably missing this iceberg of milder cases. But that’s the current circumstance we’re in.

‘Two per cent case fatality rate is comparable to the Spanish Flu pandemic in 1918 so it is a significant concern globally.’

How does the virus spread?

The illness can spread between people just through coughs and sneezes, making it an extremely contagious infection. And it may also spread even before someone has symptoms.

It is believed to travel in the saliva and even through water in the eyes, therefore close contact, kissing, and sharing cutlery or utensils are all risky. It can also live on surfaces, such as plastic and steel, for up to 72 hours, meaning people can catch it by touching contaminated surfaces.

Originally, people were thought to be catching it from a live animal market in Wuhan city. But cases soon began to emerge in people who had never been there, which forced medics to realise it was spreading from person to person. 

What does the virus do to you? What are the symptoms?

Once someone has caught the COVID-19 virus it may take between two and 14 days, or even longer, for them to show any symptoms – but they may still be contagious during this time.

If and when they do become ill, typical signs include a runny nose, a cough, sore throat and a fever (high temperature). The vast majority of patients will recover from these without any issues, and many will need no medical help at all.

In a small group of patients, who seem mainly to be the elderly or those with long-term illnesses, it can lead to pneumonia. Pneumonia is an infection in which the insides of the lungs swell up and fill with fluid. It makes it increasingly difficult to breathe and, if left untreated, can be fatal and suffocate people.

Figures are showing that young children do not seem to be particularly badly affected by the virus, which they say is peculiar considering their susceptibility to flu, but it is not clear why. 

What have genetic tests revealed about the virus? 

Scientists in China have recorded the genetic sequences of around 19 strains of the virus and released them to experts working around the world. 

This allows others to study them, develop tests and potentially look into treating the illness they cause.   

Examinations have revealed the coronavirus did not change much – changing is known as mutating – much during the early stages of its spread.

However, the director-general of China’s Center for Disease Control and Prevention, Gao Fu, said the virus was mutating and adapting as it spread through people.

This means efforts to study the virus and to potentially control it may be made extra difficult because the virus might look different every time scientists analyse it.   

More study may be able to reveal whether the virus first infected a small number of people then change and spread from them, or whether there were various versions of the virus coming from animals which have developed separately.

How dangerous is the virus?  

The virus has a death rate of around two per cent. This is a similar death rate to the Spanish Flu outbreak which, in 1918, went on to kill around 50million people.

Experts have been conflicted since the beginning of the outbreak about whether the true number of people who are infected is significantly higher than the official numbers of recorded cases. Some people are expected to have such mild symptoms that they never even realise they are ill unless they’re tested, so only the more serious cases get discovered, making the death toll seem higher than it really is.

However, an investigation into government surveillance in China said it had found no reason to believe this was true.

Dr Bruce Aylward, a World Health Organization official who went on a mission to China, said there was no evidence that figures were only showing the tip of the iceberg, and said recording appeared to be accurate, Stat News reported.

Can the virus be cured? 

The COVID-19 virus cannot be cured and it is proving difficult to contain.

Antibiotics do not work against viruses, so they are out of the question. Antiviral drugs can work, but the process of understanding a virus then developing and producing drugs to treat it would take years and huge amounts of money.

No vaccine exists for the coronavirus yet and it’s not likely one will be developed in time to be of any use in this outbreak, for similar reasons to the above.

The National Institutes of Health in the US, and Baylor University in Waco, Texas, say they are working on a vaccine based on what they know about coronaviruses in general, using information from the SARS outbreak. But this may take a year or more to develop, according to Pharmaceutical Technology.

Currently, governments and health authorities are working to contain the virus and to care for patients who are sick and stop them infecting other people.

People who catch the illness are being quarantined in hospitals, where their symptoms can be treated and they will be away from the uninfected public.

And airports around the world are putting in place screening measures such as having doctors on-site, taking people’s temperatures to check for fevers and using thermal screening to spot those who might be ill (infection causes a raised temperature).

However, it can take weeks for symptoms to appear, so there is only a small likelihood that patients will be spotted up in an airport.

Is this outbreak an epidemic or a pandemic?   

The outbreak was declared a pandemic on March 11. A pandemic is defined by the World Health Organization as the ‘worldwide spread of a new disease’. 

Previously, the UN agency said most cases outside of Hubei had been ‘spillover’ from the epicentre, so the disease wasn’t actually spreading actively around the world.

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