I've been following developments but I don't pretend to know exactly what’s happening with smoking and Covid-19.
I don't think anyone does, not with any degree of conviction.
I am grateful therefore to anyone who can explain the emerging evidence in plain English. Two articles that did just that were published online yesterday.
One (Smoking Increases Covid-19 Risk... Right?) was published on the MedPage Today website. Jason Kidde, a physician assistant at University of Utah Health, wrote:
The FDA and WHO have both made statements that smoking may increase both the risk of Covid-19 as well as severity. This assertion of risk, however, is rooted in expectation rather than data. Meanwhile, the available studies show an unanticipated protective effect on Covid-19 incidence in smokers and a less clear association with disease severity.
What follows is a useful summary of recent research including the study from France that found that 'Daily smokers accounted for 4.4% to 5.3% of all Covid-19 infections, which compares to 25.4% of the overall French population who smoke' although it also noted 'an increase in the proportion of smokers with severe illness'.
It was the latter finding that appears to have fuelled ASH’s Twitter feed last week. In a series of rotating tweets, the anti-smoking group declared, without a hint of doubt:
Kidde however is clear that this was not the principal message to take from the French study. The authors, he pointed out:
... did not mince words in their conclusion which "strongly suggests that daily smokers have a very much lower probability of developing symptomatic or severe SARS-CoV-2 infection as compared to the general population."
Significantly he concluded:
It is only natural that we jumped to what looks like the premature conclusion that smoking would result in increased Covid-19 incidence. The premise makes perfect sense, but we cannot ignore the data and continue to report this as an unfounded risk factor rooted in bias.
The second article, written by pharmacist Terry Maguire, was published on the Slugger O'Toole website and asked, 'Does Smoking Prevent Covid-19 or is it a myth?'
Covering similar ground to Jason Kidde, Maguire wrote:
A French study published last week identified an interesting relationship between smoking and contracting Covid-19. If you are a smoker you are much less likely to end up in A&E or be admitted to ICU due to Covid-19.
This finding, from this good quality study, is of particular interest since smoking was, from the early stages of the infection, identified as a major risk factor for poorer outcomes in Covid-19.
However, Chinese researches noticed early on that smokers were less likely to end up in A&E or be admitted to ICU and did publish some studies suggesting this counter intuitive fact. Only 12% of Chinese infections in ICU were smokers in a population where 52% of males are smokers. These studies were weak as many of the Covid-19 patients did not have a proper smoking status assigned.
An American study confirmed the findings but again there was significant problems with the data. So the French group, working in Paris and studying a cohort of Parisenns, in March and early April trying to ensure robust data on smoking status, covid-19 status and the degree of illness. From nearly 500 Covid-19 patients who went to A&E or were hospitalised and ended up in ICU, they found that only around 5% were daily smokers compared to the French public with a smoking prevalence of some 25%.
If you're confused or surprised by any of this I don’t blame you. After all, the public is programmed to believe there’s nothing remotely positive about smoking.
The idea that smoking - or the nicotine in tobacco - might ‘protect’ some smokers from the virus is anathema to the public health industry.
But don't worry. Even the nation’s biggest scientific brains are struggling to explain the data.
Linda Bauld, professor of public health at Edinburgh University and a leading tobacco control expert, summed it up best when she told Good Morning Britain:
“There’s something weird going on with smokers and coronavirus.”
Full marks to Bauld for her candour.
Contrast that with ASH and Public Health England. While ASH continues to pump out relentless anti-smoking propaganda (there are none so certain of the ‘truth’ than tobacco control lobbyists), PHE has gone very quiet on the subject since declaring, four weeks ago, that smokers with Covid-19 are ‘14 times more likely to develop severe respiratory disease’.
A substantial amount of data has been published since PHE’s claim echoed around the world, none of it supporting that headline-grabbing statement which was based on a single, very small study from China, yet PHE has chosen neither to amend its ‘story’ nor comment on the latest research. I wonder why.
Hopefully we will have more information soon. In the meantime I suggest all interested parties should step back, stop rushing to judgement, and focus on the overall evidence.
I’ll keep you posted.
Update: The Mail Online has just reported, More evidence smoking may cut the risk of coronavirus.