Physicians for a Smoke-Free Canada: COVID-19 and smoking

This week marks the one-year anniversary of the Director General of the World Health Organization first declaring COVID-19 a pandemic. Two months from now, on May 15, will be the 35th anniversary since the World Health Assembly identified tobacco smoking as a global pandemic. This post reflects on these two pandemics and what we have learned about the relationship between them.

Both these pandemics are leading causes of Canadian deaths.

Over the past 12 months there have been over 22,000 deaths in Canada from COVID-19 (and counting). During the same period there have been over 50,000 deaths in Canada from smoking (and counting). Smokers generally die earlier than those felled by COVID: in Canada the average age of death from smoking is about 72 years of age, while the average age of a death from COVID-19 is reported to be in the 80s.

Smoking increases the risk of severe COVID-19 outcomes

Soon after the COVID-19 pandemic was declared in 2020, reports began to appear that smoking was apparently protective against COVID-19. Early studies from France, like the one led by Miyara Makoto [1] led to widespread news reports that symptomatic COVID was less likely among smokers. Methodological problems with this and similarly-designed studies were soon identified by Anna Gilmore at the University of Bath. [2]

Since then, a number of studies have been published which not only debunk the idea that smoking might be protective, but which consistently show that smoking both increases the risk of getting symptomatic COVID-19 and of a more severe disease experience. Two recently published studies reviewed this research and conducted a meta-analysis of the data. A meta-analysis of 7 cohort studies conducted outside of China found that being (or having been) a smoker "seems to negatively impact both SARS-CoV2 infection and COVID-19 severity." [3] A study of a larger number of papers (including a review of over 1,000 scientific articles and a meta-analysis on 40 studies) concluded that current smokers had a 58% increased risk of severe COVID-19 disease and a 46% increased risk of death from COVID-19. Both studies found an increased risk also for former smokers.[4]

Vaping increases the risk of being diagnosed with COVID-19

California researchers looked at a representative population sample of American youth and young adults (aged 13-24) found that those who had ever used e-cigarettes were 5 times more likely to be diagnosed with COVID-19, and that those who used both cigarettes and e-cigarettes were 7 times more to have a COVID-19 case confirmed. [5]

The view of the World Health Organization

Like other public health authorities, the World Health Organization has worked to clarify the additional risks of COVID to smokers. Early in the epidemic, it undertook an expert review, issuing a scientific review in June 2020 which found "the available evidence suggests that smoking is associated with increased severity of disease and death in hospitalized COVID-19 patients". [6]

The view of the U.S. Centers for Disease Control

In setting priorities for COVID-19 vaccinations, the U.S. CDC included smoking as an underlying medical condition (as with chronic kidney disease, heart conditions and diabetes) which merits smokers being placed in the first 3 priority tiers for vaccination. [7] A few U.S. states (including Illinois and New Jersey) have followed this guidance.

Other authorities have other views

In setting guidance for priorization of vaccinations, Canada's National Advisory Committee on Immunization (NACI) relied on a review of risk factors for severe COVID outcomes that considered only evidence from OECD countries published before June 2020. [8] Unlike the CDC, NACI does not include smoking as an underlying additional risk for COVID. [9] The United Kingdom government's guidance on vaccination does not identify smoking as a health risk [10], based on a review of 3 studies,[11] one of which was the controversial Makoto paper. The EU's Centre for Disease Prevention on Control recognizes that smokers face a higher risk from COVID. [12]

Disinformation campaigns and other tobacco industry tactics

Public health authorities, like the WHO, have been attacked by campaigns seeking to discredit the link between smoking and severe COVID outcomes and to otherwise discredit efforts to reduce smoking. A comprehensive review of these activities is available at the TobaccoTactics website.

References