Comment by freeflight | Hacker News Reader

Comment by freeflight | Hacker News Reader

One of the more interesting differences between US prison populations and others is that smoking tobacco is way more prevalent:

> Estimated smoking prevalence among inmates was approximately 50% in 2003–2004, compared to 21% among noninstitutionalized adults. [0]

Which might play a major role in the spread and the actual severity of COVID-19 as French researchers are speculating that nicotine could be responsible for blocking the ACE2 receptors that COVID-19 uses to get into cells, which could explain why there's such a low incidence of tobacco smokers among patients, far below what should be expected [1].

There's nothing really concrete yet, for now they want to experiment with nicotine patches as treatment.

But in that context, prison populations could make for an interesting control group: Maybe the prevalence of smoking is what keeps the virus less severe, due to reduced viral load reaching cells, and thus fewer carriers are symptomatic?

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5100810/

[1] https://www.qeios.com/read/article/574

On the other hand, in China they saw more susceptibility in men, which many have thought could be related to the cultural norm for men to smoke (and women not to).

I could see this making sense for tobacco users that don't smoke (e.g. chewing tobacco) but for people that smoke...I mean this is a respiratory illness. If you have compromised lungs this seems like it would be a nightmare for smokers. Are you concerned at all with the veracity of these claims?

Not at all, I'm merely sharing information that might be interesting to this situation.

Nowhere did I declare anything as fact, I even called something "speculation" by researchers when they don't consider it much one themselves:

> There are however, sufficient scientific data to suggest that smoking protection is likely to be mediated by nicotine. SARS-CoV2 is known to use the angiotensin converting enzyme 2 (ACE2) receptor for cell entry[14-16], and there is evidence that nicotine modulates ACE2 expression[17]which could in turn modulate the nicotinic acetyl choline receptor (manuscript submitted). We hypothesize that SARS-CoV2 might alter the control of the nicotine receptor by acetylcholine. This hypothesis may also explain why previous studies have found an association between smoking and Covid-19 severity[1, 9, 10]. As hospitals generally impose smoking cessation and nicotine withdrawal at the time of hospitalization, tobacco (nicotine) cessation could lead to the release of nicotine receptors, that are increased in smokers, and to a “rebound effect” responsible for the worsening of disease observed in hospitalized smokers.

In that context, it really doesn't matter if this is a "respiratory illness", as nicotine can be applied in a number of ways, like patches.

So even tho it might seem counter-intuitive, this could be part of a plausible explanation why smokers are so underrepresented among COVID-19 patients not just in France, but also in the US and China.

Reply on news.ycombinator.com