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Smokers Are More at Risk of COVID-Like Symptoms, But Less Likely to Contract The Infection

A researcher from King’s College London discusses a paper which which looks into the relationship between smoking prevalence and COVID-19 symptoms.

Diane Caruana

July 13, 2021

The study titled, “Current smoking and COVID-19 risk: results from a population symptom app in over 2.4 million people,” had concluded that smokers are more likely to develop symptomatic COVID-19, than non-smokers.

The study included over 150,000 people with self-reported COVID-19 symptoms and over two million without such symptoms, and gathered data from over 25,000 people who were tested for SARS-CoV-2.

However, said Peter D Sasieni, a Biostatistician at King’s College London, and his team interpreted the data differently. “The paper by Hopkinson et al. provides unique and important data on smoking prevalence and COVID-19 symptoms, but their conclusion does not reflect the data well. The authors conclude ‘these data are consistent with people who smoke being at an increased risk of developing symptomatic COVID-19’,” he said.

“Based on our analysis of these more relevant data, we interpret the study differently. Our conclusion would be ‘these data are consistent with smokers having an increased risk of symptoms such as cough and breathlessness, but a decreased risk of having SARS-CoV-2 infection’.”

Contrasting findings

The daily smokers rate amongst COVID-19 patients was at 5.3%, whilst amongst the general population, the daily smokers rate was at 25.4%.

Supporting Sasieni’s arguments, an earlier study conducted in a large French university hospital, between March and April 2020, aimed to determine the possible correlation of daily smoking, with the susceptibility of contracting the SARS-CoV-2 infection. The researchers had estimated the rates of daily current smokers among COVID-19-infected patients and compared them to the rates of daily current smokers within the general French population, after controlling the data for sex and age.

The compiled data had indicated that the daily smokers’ rate amongst COVID-19 patients was at 5.3%, whilst within the general French population, the rate of daily smokers rate was of 25.4%. These findings had led the researchers to conclude that daily smokers have a significantly lower probability of developing symptomatic or a severe SARS-CoV-2 infection, when compared to the general population.

Less smokers than non-smokers are found among hospitalized COVID-19 patients

Similarly back in March, renowned anti-smoking researcher Dr. Konstantinos Farsalinos and two colleagues, analyzed data coming out of China, where it was widely speculated that the higher hospitalization and death rates among Chinese men was due to gender differences in smoking rates. However, Farsalinos found that there were significantly less smokers among hospitalized COVID-19 patients.

Another review of the Chinese data published in the European Journal of Internal Medicine concluded that “active smoking does not apparently seem to be significantly associated with enhanced risk of progressing towards severe disease in COVID-19.”

Subsequently, similar patterns started emerging from around the world. Data from the Centers for Disease Control and Prevention (CDC) have shown that smokers represented just 1.3% of COVID-19 cases analyzed, while America’s adult smoking rate is at 13.7%.

Norwegian health institute removed smoking as a risk factor for Covid

In response to these figures, in April the Norwegian Institute of Public Health removed smoking as a risk factor for severe coronavirus symptoms. While back in France, more research was launched to investigate whether nicotine patches could play a protective role against COVID-19.