Covid-19: Smoking doubles hospitalization risk, study says

Smoking doubles the risk of developing a severe case of coronavirus and requiring hospitalization, a new study claims.

The research provides the first conclusive evidence, based on real-world data, that the fact that a smoker is at higher risk for individuals than non-smokers.

Smokers were found to be 14 percent more likely to have the three main symptoms of coronavirus: fever, persistent cough and shortness of breath.

But smokers are also at greater risk of developing more than ten symptoms simultaneously – including cough, fever, loss of smell, loss of appetite, diarrhea, fatigue, confusion or muscle aches – than people who do not smoke.

According to experts, the development of myriad symptoms is often an indication of worse infection.

The data was collected from millions of Britons via the King’s College London app ZOE.

The findings, published in the BMJ journal Thorax, fall in the face of previous studies, many of which have found that smokers are less likely to catch the coronavirus or become seriously ill.

Academics are stunned by the data, as decades of research have found that smoking tobacco increases the risk of deadly diseases such as lung cancer, stroke and diabetes.

But as the pandemic progresses, new research has emerged showing that smokers who catch Covid-19 are more likely to see their disease progress rapidly and lead to death.

Dr Mario Falchi, principal investigator and senior lecturer at King’s College London, said: ‘Some reports suggest a protective effect of smoking on the COVID-19 risk.

‘Studies in this area can, however, be easily influenced by prejudices in sampling, participation and response. Our results clearly show that smokers are at greater 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 at Covid, and looked at self-reported cases and laboratory-confirmed cases.

The information from the app shows that 220,135 smokers were among the 2.4 million participants that ZOE downloaded between March 24 and April 23 last year – about 11 percent.

This is slightly lower than the UK average of 14 per cent of the population who are smokers but representative.

Participants submitted different data about themselves, any symptoms that also emerged, and any positive laboratory results.

Self-reported data are less reliable, but at this early stage of the pandemic, testing capability 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 the COVID-19 rate continues to rise and the NHS moves to capacity, it is important to do everything in our power to reduce its effects and find ways to reduce hospital admissions.

“Our analysis shows that smoking increases a person’s likelihood of visiting hospitals, so quitting smoking is one of the things we can do to reduce the health consequences of the disease.”

At the beginning of the pandemic, when little was known about SARS-CoV-2, the virus that causes Covid-19, researchers instinctively warned that smokers were at a higher risk because the coronavirus targets the respiratory system and the known link between smoking and lung cancer, stroke, diabetes and other chronic conditions targeting the same system.

Artist David Hockney proposed the idea that smokers may be less at risk because the habit fueled by nicotine hardens the immune systems and bodies of smokers, leading to tighter respiratory systems.

The 82-year-old noted in April 2020 that Greece had one of the lowest death rates in Europe, despite an above-average number of smokers. Greece has so far experienced fewer than 5,000 deaths and about 133,000 cases.

The United Kingdom, on the other hand, has recorded more than 76,000 deaths and the Office for National Statistics yesterday revealed that 1.1 million Britons are currently infected with Covid-19 – about one in 50.

Later, studies emerged that agreed with Mr. Hockney, and that finding smokers is indeed a lower risk, and experts walked around to explain how it could be and called it ‘strange’ and ‘bizarre’.

Despite the confusing evidence, the World Health Organization declared in June that smoking could make people more susceptible to COVID-19.

But a study published earlier this month in Mexico analyzed data from nearly 90,000 patients and found that smokers were 23 percent less likely than non-smokers to be diagnosed with Covid-19.

And the team also found that smokers who became infected were no longer likely to need intensive care, were connected to a ventilator or died.

University College London academics looked at 28 papers and found that the proportion of smokers among hospital patients was ‘lower than expected’.

But other studies have been published suggesting that smokers may be at greater risk, but scientists have so far struggled to provide actual data to support this.

In a recent study by academics at UCLA, there were stem cells grown by the laboratory, and found that smoking causes three times as many cells to be infected with coronavirus.

The study showed that smoking prevents the major immune system molecules, called interferons, from working properly.

Interferons are messengers that tell infected cells that they need to make proteins to attack the invasive pathogen, and are essential for fighting initial infection.

They also call for support from the broader immune system and warn uninfected cells to prepare for the virus.

The study found that smoking can no longer have the right effect, leading to a threefold increase in the number of human cells infected by the virus.

“When you think of the airways like the high walls that protect a castle, cigarettes smoke like holes in these walls,” said Dr. Brigitte Gomperts of UCLA said in November.

“Smoking reduces the natural defenses and it allows the virus.”