Coronavirus demographics — very much a risk for older people and the strange split in severe case rates 0 – 15%

The good news — babies and children appear to be not at risk. The not-so-great news, people over 80 in China have up to a 15% fatality rate (usual caveats, based on unreliable communist statistics and will hopefully be lower for many reasons, see below.) Note that even with the “one child” policy effects in China, that most western nations have a higher proportion of older folk — especially  France, Germany and Greece.

The news on “rates of severe cases” is mixed. Singapore, Japan and HK are looking at 15% early rates. But many other nations are looking at 0%. Hmm?

*Fatality rates calculated by the China CCDC won’t include many unrecorded asymptomatic infections, nor the deaths outside hospitals and don’t appear to include the lag either.  But they show which groups are at most risk.

Worldometer now gives us rates according to sex and preexisting conditions. (Reproduced below). Basically there are 30% higher death rates in men, and death rates are 6 – 10 times higher in people with heart, lung or diabetic type conditions. That is partly due to the conditions themselves, but may also just be due to the ACE2 gene — which the virus binds too. Since variants of the the ACE 2 gene increase the risk of both heart disease, high blood pressure and diabetes, it may be that those with a genetic predisposition to those conditions are also predisposed to either the infection or to the more damaging effects from the virus. Given that young people with those same genes are able to cope and recover though, it’s not all “genes”.  Managing those conditions may help reduce the risk. For some reason, younger people don’t seem to progress to the cytokine cascade — the inflammatory response that gets out of hand.

The all important rates of progression to severe cases is spread from zero to 15%

Adjusted for the eight day delay in progression to severe symptoms, the number that keeps coming back is  strangely split at close to zero, or an unappealing 14% — Singapore has 4 severe cases out of the 28 it had on Feb 11th. (14%) Hong Kong had 49 cases on Feb 11th, and 7 have progressed to severe or critical. 14%. In Japan there were about 28 cases a week ago, and 4 of those are severe. (14%).  The Diamond Princess cases: 15%  severe (see below).

But in many places the news is good. South Korea is interesting, with 46 cases and still none classed as “severe”. Fifteen of those cases are only one day old, so don’t count, but 28 of those cases are eight days or more after diagnosis. This is encouraging. As is the lack of any “severe” progression in Australia (only five active cases left) and in the US, Germany, and France (apart from one death of a Chinese man, ten of the other cases are now at least ten days old and haven’t progressed.) Taiwan, likewise, had 18 cases a week ago, and apart from one death, none of the others have progressed to severe.

Why the disparity? Statistical fluke perhaps (South Korea only needs 4 severe cases to put it in the same category as Singapore et al)? Otherwise, genes, culture, diet, weather, hospitals and medical systems? Or possibly some strains of the virus may be evolved to be nicer already.

The Diamond Princess: — it ain’t over yet:

On Feb 11th there were 135 cases. Today there are 542, with 20 being severe. So about 15% of cases progress to serious (20/135).  We don’t know the ethnic or genetic breakdown, though we can guess the rates are higher because of the demographic spread. Cruise ships probably have few people from 0 – 40 years old.

Since there were another 88 new cases today that tested positive, clearly Cruise-ship-quarantine is a bad plan. There are fears that the Diamond Princess may yet spark a global spread:

 With people aboard hailing from more than 50 countries, the end of the quarantine raises worries the vessel could become the source of a fresh wave of global infections.

Undoubtedly these 88 new cases will not be the last new cases, and though the US, Australia, Canada, South Korea and other nations are wisely insisting on a further two weeks of proper quarantine, but Japan is not, and the Netherlands didn’t either. With 76 cases already inside Japan (presumably not former passengers of the cruise) they have apparently given up containment.

One expert in Hong Kong, who ought to know what’s going on, advised that even people who test negative today could test positive in a few days. Keiji Fukuda, the director of the School of Public Health at Hong Kong University thinks more quarantine is needed. Meanwhile another expert in Japan, who ought to know too, says the opposite:

An expert on infectious diseases said Japan has focused on preventing the virus from causing more fatalities. “My view is that Japan’s effort will be evaluated later not on the level of expansion of the spread, but on the rate of mortality,” said Shigeru Omi, a former WHO official who now sits on the Japanese government’s expert panel on the coronavirus. “That’s why our focus is now on community prevention control so that we can reduce mortality rate and lower the speed of expansion,” he said. “It’s impossible to stop transmission.”

So Japan is going to hope those who test negative and have no symptoms can wander around the nation and not infect too many others. Hope that works out for them. It doesn’t seem like a good strategy when their early rates show that 15% in Japan may suffer the severe form.

The world may become split between the no-virus states and the infected ones — call me an optimist — all clean countries need a two week mandatory quarantine as a barrier. Or we may (cheery thought) be in the early stages of a pandemic.

What to do if you are an 80 year old — especially with a high risk condition?

Time to think about improving preexisting conditions (make those doc appointments, fill those scripts, do that exercise, consider eating better). Think about the options if the virus starts to spread locally. Hopefully it wont. But there may come a point where having a stash of things at home and cutting back on shopping trips, parties and nightclubs will improve the odds. Buying up things that will be used anyway in the next few months seems like a low cost form of insurance, as long as they are stored well.

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Best case: West contains the spread

The Optimistic Mantra (repeated):  Covid 19 will likely be less severe outside China due to cleaner air, healthier lungs, better diets, lower population density, possibly genes (ACE2 receptor), cultural habits, more sun, better nutrition, lower rates of smoking, and better medical systems.  We also got a head-start and, if we are not totally stupid, we might use that to our advantage. We hope we can stay above all this and help the poor sods stuck in China, and probably Africa, and possibly Indonesia, India, etc. We won’t be much use to them if we lose control ourselves. We really really don’t want to get on the wrong side of that exponential growth curve.

If countries manage to avoid the hospital meltdown the big impact from Covid 19 might be the economic fallout. Think about what you might need that is made in China, or rather, used to be made in China. Shelves may get quite empty of a few things in the next two months.

There are hints that the draconian Chinese lock downs might be slowing the spread. But even if that is the case there are many weeks yet of this to play out.

 COVID-19 Fatality Rate by SEX:

Source: Age and Sex of COVID-19 Deaths

Pre-existing medical conditions

Patients who reported no pre-existing (“comorbid”) medical conditions had a case fatality rate of 0.9%. Pre-existing illnesses that put patients at higher risk of dying from a COVID-19 infection are:

COVID-19 Fatality Rate by COMORBIDITY:

Source: Age and Sex of COVID-19 Deaths

REFERENCE:

The Epidemiological Characteristics of an Outbreak of 2019 Novel Coronavirus Diseases (COVID-19) – China CCDC, February 17 2020