Emily
Editor, Senior Moderator
https://www.nature.com/articles/s41533-021-00223-1
van Westen-Lagerweij, N.A., Meijer, E., Meeuwsen, E.G. et al. Are smokers protected against SARS-CoV-2 infection (COVID-19)? The origins of the myth. npj Prim. Care Respir. Med. 31, 10 (2021). https://doi.org/10.1038/s41533-021-00223-1
A number of recent studies have found low percentages of smokers among COVID-19 patients, causing scientists to conclude that smokers may be protected against SARS-CoV-2 infection. National and international media were interested in this story and we soon began receiving questions about this topic in general practice. In this article, we shed light on the process that resulted in the misinterpretation of observational research by scientists and the media. We also point out the methodological flaws of various studies on which hasty conclusions were based. Finally, we address the role of primary healthcare providers in mitigating the consequences of erroneous claims about a protective effect of smoking.
Recently, a number of observational studies found an inverse relationship between smoking and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 (COVID-19)), leading to a (social) media hype and confusion among scientists and to some extent the medical community. The finding that smoking is not associated with SARS-CoV-2 infection contradicts earlier studies which found that smokers are more vulnerable to infections in general and to respiratory infections in particular. Smoking is known to increase the risk of infection of both bacterial and viral diseases, such as the common cold, influenza and tuberculosis[SUP]1[/SUP], and smoking is a putative risk factor for Middle East respiratory syndrome coronavirus infection[SUP]2[/SUP]. Could it be possible that SARS-CoV-2 is the big exception to the rule? To date, there is no strong evidence (i.e., evidence based on causal research) that smokers are protected against SARS-CoV-2 infection. Moreover, there is growing evidence that smokers have worse outcomes after contracting the virus than non-smokers[SUP]3[/SUP].
If there is no strong evidence that smokers are protected against SARS-CoV-2 infection, how is it possible that such a potentially dangerous claim gained so much attention? Due to the great need for knowledge about COVID-19 and the associated ‘publication pressure’, several manuscripts were quickly published in peer-reviewed journals without undergoing adequate peer review. Also, many manuscripts did not initially follow the traditional time-consuming peer review process but were immediately shared online as a preprint. Although scientific discussions could be continued afterwards on the preprint servers, the media and many scientists did not follow these discussions. As a result, studies designed to report correlations within a non-causal framework were quickly picked up via (social) media and presented within a causal framework. We now know that <20% of COVID-19 preprints actually received comments[SUP]4[/SUP]. Also, <50% of the COVID-19 preprints uploaded in the first few months of the pandemic (January–April) have been published in peer-reviewed journals so far[SUP]5[/SUP]. Both findings emphasise the great caution needed in interpreting (social) media claims of preprint results.
It seems the tobacco industry benefited from the (social) media hype, since exposure to claims about a protective effect of smoking was associated with an increase in tobacco consumption among Chinese citizens during the pandemic[SUP]6[/SUP]. Also in other countries, an increase in tobacco consumption among smokers has been reported[SUP]7,8[/SUP], possibly influenced by this hype. In France, researchers first suggested that nicotine may play a role in protecting smokers[SUP]9[/SUP], triggering a run on nicotine products among the general public. Interestingly, the lead author of this research has been funded by the tobacco industry in the past, and also other researchers who have made similar claims can be linked with the tobacco industry, indicating a possible conflict of interest. According to the Global Center for Good Governance in Tobacco Control, the tobacco industry was actively involved in downplaying the role of smoking in COVID-19 by spreading claims that smoking or vaping protects against COVID-19[SUP]10[/SUP]....
van Westen-Lagerweij, N.A., Meijer, E., Meeuwsen, E.G. et al. Are smokers protected against SARS-CoV-2 infection (COVID-19)? The origins of the myth. npj Prim. Care Respir. Med. 31, 10 (2021). https://doi.org/10.1038/s41533-021-00223-1
A number of recent studies have found low percentages of smokers among COVID-19 patients, causing scientists to conclude that smokers may be protected against SARS-CoV-2 infection. National and international media were interested in this story and we soon began receiving questions about this topic in general practice. In this article, we shed light on the process that resulted in the misinterpretation of observational research by scientists and the media. We also point out the methodological flaws of various studies on which hasty conclusions were based. Finally, we address the role of primary healthcare providers in mitigating the consequences of erroneous claims about a protective effect of smoking.
Recently, a number of observational studies found an inverse relationship between smoking and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 (COVID-19)), leading to a (social) media hype and confusion among scientists and to some extent the medical community. The finding that smoking is not associated with SARS-CoV-2 infection contradicts earlier studies which found that smokers are more vulnerable to infections in general and to respiratory infections in particular. Smoking is known to increase the risk of infection of both bacterial and viral diseases, such as the common cold, influenza and tuberculosis[SUP]1[/SUP], and smoking is a putative risk factor for Middle East respiratory syndrome coronavirus infection[SUP]2[/SUP]. Could it be possible that SARS-CoV-2 is the big exception to the rule? To date, there is no strong evidence (i.e., evidence based on causal research) that smokers are protected against SARS-CoV-2 infection. Moreover, there is growing evidence that smokers have worse outcomes after contracting the virus than non-smokers[SUP]3[/SUP].
If there is no strong evidence that smokers are protected against SARS-CoV-2 infection, how is it possible that such a potentially dangerous claim gained so much attention? Due to the great need for knowledge about COVID-19 and the associated ‘publication pressure’, several manuscripts were quickly published in peer-reviewed journals without undergoing adequate peer review. Also, many manuscripts did not initially follow the traditional time-consuming peer review process but were immediately shared online as a preprint. Although scientific discussions could be continued afterwards on the preprint servers, the media and many scientists did not follow these discussions. As a result, studies designed to report correlations within a non-causal framework were quickly picked up via (social) media and presented within a causal framework. We now know that <20% of COVID-19 preprints actually received comments[SUP]4[/SUP]. Also, <50% of the COVID-19 preprints uploaded in the first few months of the pandemic (January–April) have been published in peer-reviewed journals so far[SUP]5[/SUP]. Both findings emphasise the great caution needed in interpreting (social) media claims of preprint results.
It seems the tobacco industry benefited from the (social) media hype, since exposure to claims about a protective effect of smoking was associated with an increase in tobacco consumption among Chinese citizens during the pandemic[SUP]6[/SUP]. Also in other countries, an increase in tobacco consumption among smokers has been reported[SUP]7,8[/SUP], possibly influenced by this hype. In France, researchers first suggested that nicotine may play a role in protecting smokers[SUP]9[/SUP], triggering a run on nicotine products among the general public. Interestingly, the lead author of this research has been funded by the tobacco industry in the past, and also other researchers who have made similar claims can be linked with the tobacco industry, indicating a possible conflict of interest. According to the Global Center for Good Governance in Tobacco Control, the tobacco industry was actively involved in downplaying the role of smoking in COVID-19 by spreading claims that smoking or vaping protects against COVID-19[SUP]10[/SUP]....