Study claims smoking DOES increase your risk of developing COVID-19 symptoms and ending up in hospital – flying in the face of previous research
- KCL researchers assessed data from more than two million people via ZOE app
- Around 11 per cent of people in the study classified themselves as smokers
- Smokers 14% more likely to suffer cough, shortness of breath and fever
- But smokers are more than twice as likely to end up in hospital after infection
Smoking doubles the risk of developing a severe case of coronavirus and needing hospitalisation, a new study claims.
The research provides the first conclusive evidence, based on real-world data, that being a smoker puts individuals at higher risk of severe disease than non-smokers.
It found smokers are 14 per cent more likely to have the three main symptoms of coronavirus: fever, persistent cough and shortness of breath.
But smokers are also at 50 per cent greater risk of developing more than ten symptoms at once — including cough, fever, loss of smell, loss of appetite, diarrhoea, fatigue, confusion or muscle pain — than people who do not smoke.
Development of myriad symptoms is often an indicator of more severe infection, experts believe.
The data was gathered from millions of Britons via the King’s College London app ZOE.
The findings, published in the BMJ journal Thorax, fly in the face of previous studies, many of which have found smokers are less likely to catch the coronavirus or get severely ill.
Academics have been left baffled by the data, given that decades of research has found smoking tobacco increases the risk of deadly diseases such as lung cancer, strokes and diabetes.
But as the pandemic has progressed fresh research has emerged which shows smokers who catch Covid-19 are more likely to see their disease rapidly progress and lead to death.
There have been conflicting reports on the impact of smoking on a Covid patient’s prognosis, with some studies finding it reduces risk, and others finding the opposite. Now, data from KCL shows smokers are twice as likely to be hospitalised than non-smokers
Dr Mario Falchi, lead researcher and Senior Lecturer at King’s College London said: ‘Some reports have suggested a protective effect of smoking on COVID-19 risk.
‘However, studies in this area can easily be affected by biases in sampling, participation and response. Our results clearly show that smokers are at increased risk of suffering from a wider range of COVID-19 symptoms than non-smokers.’
The latest study from KCL provides real information on patients living with Covid, and looked at both self-reported cases and lab-confirmed cases.
Data from the app shows that, of the 2.4million participants who downloaded ZOE between March 24 and April 23 last year, 220,135 were smokers – around 11 per cent.
Smoking e-cigarettes increases risk of Covid-19 diagnosis by 500%
A study by Stanford University academics assessed the relationship between Covid-19 and smoking.
This piece of research aimed to assess whether youth cigarette and electronic cigarette (e-cigarette) use are associated with coronavirus disease 2019 (COVID-19) symptoms.
An online national survey of 4,351 adolescents and young adults aged 13–24 years was conducted in May 2020.
COVID-19 diagnosis was five times more likely e-cigarette smokers.
It was seven times more likely in people who smoked both.
‘There are a number of potential reasons why both dual use and e-cigarette use were associated with getting infected with COVID-19,’ the researchers write.
‘Heightened exposure to nicotine and other chemicals in e-cigarettes adversely affects lung function, with studies showing that lung damage caused by e-cigarettes is comparable to combustible cigarettes.’
This is slightly lower than the UK-wide average of 14 per cent of the population being smokers but was representative, the researchers say.
Participants submitted various pieces of data about themselves, any symptoms that emerged as well, and any positive lab results.
Self-reported data is less reliable, but at this early stage of the pandemic the testing capacity was a fraction of what it is now and was only available in hospitals.
Claire Steves, lead researcher, consultant physician and Reader at King’s College London, said: ‘As rates of COVID-19 continue to rise and the NHS edges towards capacity, it’s important to do all we can to reduce its effects and find ways to reduce hospital admissions.
‘Our analysis shows that smoking increases a person’s likelihood to attend hospitals, so stopping smoking is one of the things we can do to reduce the health consequences of the disease.’
At the start of the pandemic, when little was known about SARS-CoV-2, the virus which causes Covid-19, researchers instinctively warned smokers would be at higher risk, due to the fact the coronavirus targets the respiratory system and the known link between smoking and lung cancer, strokes, diabetes and other chronic conditions that target this same system.
Artist David Hockney first suggested the idea that smokers may be less at risk because the nicotine-fuelled habit hardens the immune systems and bodies of smokers, leading to tougher respiratory systems.
The 82-year-old noted in April 2020 that Greece had one of the pandemic’s lowest death tolls in Europe, despite having an above-average number of smokers. Greece has to-date experienced fewer than 5,000 deaths and around 133,000 cases.
The UK, in contrast, has recorded more than 76,000 deaths and the Office for National Statistics revealed yesterday that there are currently 1.1million Britons infected with Covid-19 – around one in 50.
Studies later emerged which agreed with Mr Hockney, finding smokers may indeed be at reduced risk, and experts floundered to explain how this could be, calling it ‘weird’ and ‘bizarre’.
Despite the confounding evidence, the World Health Organization declared in June that smoking may make people more susceptible to COVID-19.
But a study published earlier that month from Mexico analysed data from almost 90,000 patients and found smokers were 23 per cent less likely than non-smokers to get diagnosed with Covid-19.
Smoking cigarettes increases the risk of severe coronavirus infection by dampening the immune response of the body, a new study suggests.
Lab studies on airway models made from human stem cells reveals smoking stops key immune system molecules, called interferons, from working properly.
Interferons are messengers that tell infected cells to make proteins to attack the invading pathogen, and are essential for fighting off initial infection.
They also summon support from the wider immune system and warn uninfected cells to prepare for the virus.
The study found smoking stops this pathway from working properly, and this causes up to a threefold increase in the number of human cells infected by the virus.
And the team also found smokers who did get infected were no more likely to need intensive care, be hooked up to a ventilator, or die.
University College London academics looked at 28 papers and found the proportion of smokers among hospital patients was ‘lower than expected’.
But other studies have been published suggesting smokers may be at increased risk, however scientists have, until now, struggled to provide real-world data to support this.
A recent study by academics at UCLA used lab-grown stem cells and found smoking causes three times as many cells to be infected with coronavirus.
The study showed smoking stops key immune system molecules, called interferons, from working properly.
Interferons are messengers that tell infected cells to make proteins to attack the invading pathogen, and are essential for fighting off initial infection.
They also summon support from the wider immune system and warn uninfected cells to prepare for the virus.
The study found smoking stops this pathway from working properly, and this causes up to a threefold increase in the number of human cells infected by the virus.
‘If you think of the airways like the high walls that protect a castle, smoking cigarettes is like creating holes in these walls,’ Dr Brigitte Gomperts, from UCLA, said in November.
‘Smoking reduces the natural defenses and that allows the virus to set in.’
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