The role of nicotine in COVID-19 infection

May 26, 2020

Jamie Hartmann-Boyce and Nicola Lindson

On behalf of the Oxford COVID-19 Evidence Service Team
Centre for Evidence-Based Medicine, Nuffield Department of Primary Care Health Sciences
University of Oxford

Correspondence to jamie.hartmann-boyce@phc.ox.ac.uk


VERDICT
There are biologically plausible pathways through which nicotine may impact SARS-CoV-2, but the clinical significance of these is entirely unclear.

 

BACKGROUND
There is mixed evidence on the role of smoking in COVID-19 infection and associated outcomes. Whereas the expectation is that smoking would predispose to worse outcomes from COVID-19, as is the case in other acute respiratory infections, some (but not all) studies of COVID-19 have detected fewer people who smoke than would be expected in hospitalised patients with COVID-19. It is unclear whether this is due to biases, confounding, misreporting, or a potential protective effect of smoking on COVID-19 outcomes. Irrespective of COVID-19, smoking is uniquely deadly. However, nicotine, the addictive component of cigarettes, can be safe when used in other forms, and there is some biological plausibility regarding a possible role of nicotine in COVID-19 infection. Below we briefly review evidence to date on the role of nicotine in COVID-19. This is important to people who smoke, but it could also be of general relevance, as some have hypothesised nicotine may be a potential treatment for COVID-19.

CURRENT EVIDENCE
We searched the literature for studies relating to COVID-19 and nicotine. Some are underway, and this piece will be updated as new findings emerge. In the meantime, the available research literature is mainly in the form of speculative commentaries, with some lab studies also reported. 

Commentaries regarding nicotine and COVID-19 all agree nicotine potentially has a role to play based on its role in the renin-angiotensin system. In particular, nicotine can impact the angiotensin-converting enzyme (ACE) 2, which is relevant because coronaviruses bind to ACE2. However, some authors interpret this as suggesting nicotine is likely to be harmful in the context of COVID-19, and others suggest the opposite.

It is extremely difficult to synthesise evidence on nicotine and COVID-19 as much of the literature is inconsistent. Below we highlight pathways/hypothetical mechanisms through which at least one paper has speculated nicotine might impact SARS-Cov-2:

France has had to place restrictions on sales of nicotine replacement therapy because of fears it may start to be stockpiled for inappropriate use relating to COVID-19. Studies are underway testing nicotine replacement therapy in COVID-19 patients, and until results are available from those, there is no evidence to support the general public’s use of nicotine replacement therapy for COVID-19 infection. Nicotine replacement therapy is a mainstay of smoking cessation treatment and is safe and effective in this capacity. 

CONCLUSIONS

  • There are biologically plausible pathways through which nicotine may impact SARS-CoV-2, but the clinical significance of these is entirely unclear
  • Early studies are underway regarding the role of nicotine replacement therapy as a therapeutic aid for COVID-19
  • Evidence so far is too limited to inform any decisions about use of nicotine replacement therapy in COVID-19
  • When used for smoking cessation, there is high certainty evidence that nicotine replacement therapy is safe and effective.

End.

Disclaimer:  the article has not been peer-reviewed; it should not replace individual clinical judgement and the sources cited should be checked. The views expressed in this commentary represent the views of the authors and not necessarily those of the host institution, the NHS, the NIHR, or the Department of Health and Social Care. The views are not a substitute for professional medical advice.

AUTHORS

Jamie Hartmann-Boyce is a departmental lecturer and deputy-director of the Evidence-Based Health Care DPhil programme within the Centre for Evidence-Based Medicine in the Nuffield Department of Primary Care Health Sciences, University of Oxford. She works with the Cochrane Tobacco Addiction Group and is an associate editor of Addiction.

 

Nicola Lindson is a Senior Researcher in the Health Behaviours team within the Nuffield Department of Primary Care Health Sciences, University of Oxford. She works with the Cochrane Tobacco Addiction Group.

 

 

 SEARCH TERMS
Searches run 19 May 2020

(coronavirus OR covid-19) AND nicotineGoogle and Google Scholar
((coronavirus*[Title] OR coronovirus*[Title] OR coronoravirus*[Title] OR coronaravirus*[Title] OR corono-virus*[Title] OR corona-virus*[Title] OR “Coronavirus”[Mesh] OR “Coronavirus Infections”[Mesh] OR “Wuhan coronavirus” [Supplementary Concept] OR “Severe Acute Respiratory Syndrome Coronavirus 2″[Supplementary Concept] OR COVID-19[All Fields] OR CORVID-19[All Fields] OR “2019nCoV”[All Fields] OR “2019-nCoV”[All Fields] OR WN-CoV[All Fields] OR nCoV[All Fields] OR “SARS-CoV-2”[All Fields] OR HCoV-19[All Fields] OR “novel coronavirus”[All Fields])) AND ((“Tobacco Use Cessation Devices”[Mesh]) OR (nicotine[Title/Abstract] OR nrt[Title/Abstract]))12PubMed
term “(covid-19 OR coronavirus) AND nicotine”25medRxiv
nicotine OR nrt15LitCOVID

 

REFERENCES
References linked to from text