Why does the coronavirus spread so easily between people?

https://www.nature.com/articles/d41586-020-00660-x

by pseudolus • 6 years ago

178 95 6 years ago

Alex39173• 6 years ago

Their experiments have shown that the spike protein binds to a receptor on human cells — known as angiotensin-converting enzyme 2 (ACE2) — at least ten times more tightly than does the spike protein in the SARS virus. Veesler’s team has also found this, which suggests that the receptor is another potential target for vaccines or therapies. For example, a drug that blocks the receptor might make it harder for coronavirus to enter cells.

First, let me say that although the government doesn't formally recognize me as a doctor, I watch a lot of medical stuff on TikTok so I'm basically getting my MD 7 seconds at a time.

That aside, this seems dubious to me; if anything it's likely better to take ACE inhibitors now so that your body makes more ACE2 receptors before you get the virus. One of the ways the virus kills people is by detroying their ACE2 receptors, which your lung cells need in order to function. Downregulating them is unlikely to prevent the virus from getting into your cells, rather it will just leave your cells with less healthy ones left over after the virus destroys the ones it uses to enter your cells.

As evidence from this epidemic, smoking cigarettes upregulates your ACE2 receptors, and smokers are less likely to get serious illness from COVID-19. Of course if they do get seriously ill then they're more likely to die, but this is probably just because of the lung damage caused by smoking. At the very least it seems irresponsible to put out a statement like this without saying that all the available evidence currently points the opposite way, as does the evidence from the SARS epidemic.

spdionis• 6 years ago

smokers are less likely to get serious illness from COVID-19

Source? I thought the contrary.

mrandish2• 6 years ago

I've been watching the firehose of pre-prints, raw data and community analysis at reddit.com/r/COVID19 and

* Initially it looked like maybe smoking was a notable risk factor.

* Then some data from a different population seemed to indicate maybe smoking was protective.

* Then further analysis indicated that all this data was likely skewed by upstream sampling bias (like pretty much all CV19 data so far).

* The latest speculation is that maybe smoking makes one less likely to catch CV19 but if you've are a heavy smoker currently (or recently), once you have CV19 your outlook is worse (but nowhere near as bad as being over 60 or immuno-compromised). This was based on a more recent study which seemed to have better data because it went narrow and deep on a few cases, however, it has the disadvantages of small sample size.

* My best guess is that the last bullet might be directionally correct but effect size is small enough that it could easily be swamped by other factors.

In general, us "armchair analysts" obsessively scraping the raw data sources and modeling on it quickly realize that all of the data is very noisy since different regions are using different criteria for what counts as a "case", "severe" and even "hospitalization". Plus no country is sampling the population in a consistent way because they have different criteria to get a test (which can also change daily and by area). For example, Italy's numbers look really troubling in terms of severity and progression until you look at the median ages of who they are testing, which skews 13 years older than their overall population.

maayank• 6 years ago

and smokers are less likely to get serious illness from COVID-19.

Source? Genuinely interested

Alex39173• 6 years ago

https://www.reddit.com/r/COVID19/comments/fdb2g6/new_study_r...

https://www.reddit.com/r/COVID19/comments/fbodxp/study_finds...

https://www.reddit.com/r/COVID19/comments/f8wldm/unlike_appa...

https://www.reddit.com/r/COVID19/comments/ff06im/bulk_and_si...

dghughes• 6 years ago

That sounds unusual since smoking in China seems ubiquitous.

decebalus1• 6 years ago

Anecdotally, it would make sense, right? Back when I used to smoke, whenever there was the flu season I went full blown bronchitis most of the time, while the rest of my family had only mild symptoms. Smoking is already known to aggravate any flu symptoms to the point of escalating to a more serious condition.

kaiabwpdjqn2• 6 years ago

I noticed this smoker effect early on! Data from China was showing about 20% of the infected population was smokers, while smoking is closer to 60% in Chinese men (by cursory google search). The death rates were much higher for infected smokers, but they were curiously underrepresented.

This has a really interesting double effect if you think about it. In places with lots of smokers, fewer people will get the disease, but a larger proportion will die from it. Both of those effects will magnify the death rate.

Edit: assuming the protection is additive and not proportional to existing rates across ages

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DailyHN• 6 years ago

What about former smokers?

I imagine that, depending on the mechanism of action, and whether the "increased immunity" remains, there could something reproducible to reduce transmission.

Reply

bhanhfo• 6 years ago

I upvoted this just because of the nature.com link - but after I actually read it, I am disapointed. Summary: