2019 nCoV (COVID-2019) (coronavirus) confounding factors in China relative to the USA
With the likely exception of people with primary Native American ancestry, who may die at 2 to 25 times the rate of everyone else, I think that the mortality rate should be considerably lower in the USA and Europe. China has done an incredible job of developing its economy and modernizing in the last 25 years, however, China is still a nation struggling with developing nation issues like TB, high rates of tobacco smoking, and serious air pollution. The exception, as I said, is that the Americas north and south have a special problem among people of native American ancestry being more susceptible to death from respiratory viruses.
However, what should hold true is the relative distribution of deaths. Our country should see something very close, with the possible exception of Native Americans.
Confounding factors in China vs. USA: ~50% of men in China smoke, which is probably related. The roughly doubled death rate among men versus women correlates pretty precisely. Sex should be a surrogate for smoking in China, because only 2.7% of Chinese women smoke, although they get smoke second hand. That said, generally, women have stronger immunity than men do. So, on average, I’d expect some difference there without smoking, but not double the mortality rate.
Smoking appears to be a factor for influenza mortality. So, I think this is probably why we see double the number of men dying in China.
https://www.ncbi.nlm.nih.gov/pubmed/30789425
TB is probably a factor. The 1917–18 influenza pandemic had a strong male tilt. This was probably due in significant part to latent and active TB, which is strongly suggested by the evening out of TB rates between male and female after the 1917–18 epidemic.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2740912/
TB in Hubei is in the top 10 in China, with a TB rate of 1:1000.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0080969
Air quality isn’t good. Wuhan has many days where air quality is worse than 200. The day this article was written, it was at 248 until daily breeze cleared it to the 170’s. All of China is notorious for poor air quality due to coal power production without precipitators in the stacks. This is probably the least significant factor, but people living in an area with heavy particulate pollution should have lung effects.
https://aqicn.org/city/wuhan/
Air pollution in the USA is estimated to cause 90,000 to 360,000 premature deaths per year. Which is another data point for comparison. Our air quality is far better than China’s is these days. However, I will note that the current administration is working on moving the USA in the direction of China’s air pollution.
https://www.sciencemag.org/news/2020/02/deadly-air-pollution-blowing-your-state-surprisingly-large-source
Reported cases, Feb 14, 2020 : 40,655 deaths: 910
Reported cases, Feb 25, 2020: 80,370 deaths: 2707
https://www.worldometers.info/coronavirus/
Real mortality is still up in the air. From my reading, around 80% will get mild disease. About 14% progress to more severe disease. Some unknown fraction of severe cases show up at hospitals.
Doing the math, with 1 in 1000 people in Hubei (with a likely tilt toward men I am not trying to account for) having TB, and 43,200 cases reported in China at the time of this calculation, that could account for 43.2 deaths. To get to 910 deaths, requires a multiplying factor of 21 times.
The true number of cases could be ~10 times the number reported. So, that would get us to roughly half the deaths reported. It’s not out line to think that TB is a significant factor in COVID-2019 deaths.
The Americas have a high fraction of native Americans. Native Americans died in the 1917–18 pandemic at much higher rates. One village in northern Canada had 50% total population loss with the best supportive care of the time. There are records from the earliest colonies of 95% die-off of Native Americans from exposure to influenza, and what appeared to be likely cold viruses that just made the settlers ill without killing anyone[1]. Note that most coronaviruses have cold-like symptoms.
In the continental USA, there are few Native Americans without some Caucasian/Asian/African HLA genes to confer resistance. As you go south of the US border, and way out into the northern parts of Canada and Alaska, this becomes less the case. The deserts, the altiplano and very moist and warm jungle environments helped protect them from enveloped aerosol viruses.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2893155/
Whether there is a correlation between native American genetic heritage (e.g. Latinos) and influenza mortality is an open question. Records weren’t kept, and literature mostly attributes mortality differentials to poverty.
https://ajph.aphapublications.org/doi/10.2105/AJPH.2009.161505
Poverty does matter for health outcome, but without genetic identification it’s not possible to be sure what the differential is.
For what it’s worth, these are the most current figures, which I compare where possible to influenza and SARS.
My take:
- I suspect that the combination of a high rate of smoking tobacco (25% overall, 50% in men) together with a high TB rate of 1:1000 in Hubei, and poor air quality is probably raising the death toll in China by more than double.
- I suspect that Native Americans will have a much worse time with this virus. It is possible that Latinos may have higher morbidity and mortality as well, for reasons other than income differential.
- With the exception of people of native American primary ancestry, I think the USA death rate will at most be half what we see in China, and probably considerably lower. With this past flu season causing 12,000–30,000 deaths between Oct 1, 2019 and Feb 1, 2020, one wonders if Wuhan-2019-nCoV could surpass it in the USA or not.
1. Cites available for early die-off records if desired. I have an archive from a back burner manuscript I stopped work on when I would have had to spend 6–12 months at archives going through paper documents. I got approval to do it, but didn’t have the time nor money for it.
