Thursday, May 14, 2020

Herd Immunity Sociopathy

Western Cape Cases and Deaths by Age
Medical people like to talk about "Herd Immunity" for the Coronavirus like it's the most natural thing, and some people are saying we should get the population to this level of infection as soon as possible, and then the COVID-19 epidemic will all be over. Personally, I think this is a diabolical notion.
Let's look at the numbers for South Africa for a moment. There are 58 million people, of which 1% of the population has TB, and 7% of the population has Diabetes. Children make up 34% of the total population. Two-thirds of children live in the poorest 40% of households.
This makes a complicated but dangerous mess, because so many people are sick or vulnerable. Social grants are paid to 11 million people. Mercifully, the number of cases so far is a fraction of a percent of the population.
But what happens when it gets to 1%? That would mean that 580,000 people test positive. Based on the Iceland numbers, 50% of those who tested positive have no recognized symptoms for COVD-19. So let's be optimistic and halve that number to 290,000 people who display enough symptoms to be regarded as a "case". 1% will have TB, and 7% will have Diabetes. Some will have both. We have no idea whether the ARV drugs used to treat HIV have any impact on the Coronavirus, so let's ignore the 7.7 million HIV patients for now. Let's say that 7.5% of the 290,000 people have TB and/or Diabetes, namely 21,750 people. They are all likely to need medical attention, probably a hospital visit. At the time of writing, 4.41% of resolved cases result in death. That's 959 of the 21,750 people. The worldwide statistic is 15%. I have not used the Case Fatality Rate (CFR) because it isn't accurate during an outbreak. The pessimist in me says that a lot more than 4% of these patients are going to die, given their vulnerability. If we assume the world average then 3,262 of them will die. In any case, of the 290,000 people (less 21,750) 11,830 people will die if the 4.41% figure remains constant. So with 1% of the population infected, somewhere between 12,789 and 15,092 people will die.
This is where things start getting tricky. The required infection rate for "herd immunity" is 80% of the population should be infected, assuming that herd immunity actually works. So to get there we can expect between 1,023,120 and 1,207,360 people will have to die. That was obtained by multiplying the 1% death toll by 80. Frankly that's a catastrophic number. So what if we assume that a tiny fraction of the children die, and therefore we can multiply the 80% by (1-0.34) to allow for 34% of the population being children. We multiply the death toll by 52.8 instead of 80. So now the death toll is between a trifling 675,259 and a mere 796,857 (average 736,058) which is more than the population of the city of Bloemfontein (556,000 to 747,431).
Based on the discussions I have had with a few of the herd immunity advocates, they reckon "those people would have died anyway". What!? We have 9.1 deaths per 1000 population each year, or 527,800 per year on average, from all causes, including road deaths, suicide, homicide, old age, disease and industrial accidents.

Accidents, homicides, suicides and external causes account for roughly 10% of the deaths each year, but what percentage of the other causes of death are accelerated by the extra COVID-19 fatalities? Your guess is as good as mine, but there will be a lot of extra dead bodies. Since I used 15% for the TB and Diabetes group, let's use that for all the groups. Its as good as any other guess. That would mean that we would have an additional 670,000 deaths, and the "rest would have died anyway".
Note that I have not mentioned any of the "hard lockdown" methods to "flatten the curve" in this discussion. That is for another blog entry.

Replacing Herd Immunity

There is no herd immunity for flu, as far as I understand it. We have a vaccine every year that is different every year, based on the strains of flu from the previous few years. It doesn't confer immunity to any of the newer strains of flu, whether they are Corona viruses or other types. Similarly the Spanish Flu was more deadly in the second wave than the first, even affecting those who survived the first wave. So there is not much hope that herd immunity will do anything in the long term, other than kill off 670,000 people. So let's consider a different way of fending off the infections, written by David Ewing Duncan on 8th May:
It sounds too good to be true. But a compelling new study and computer model provide fresh evidence for a simple solution to help us emerge from this nightmarish lockdown. The formula? Always social distance in public and, most importantly, wear a mask.
If you’re wondering whether to wear or not to wear, consider this. The day before yesterday [6th May 2020], 21 people died of COVID-19 in Japan. In the United States, 2,129 died. Comparing overall death rates for the two countries offers an even starker point of comparison with total U.S. deaths now at a staggering 76,032 and Japan’s fatalities at 577. Japan’s population is about 38% of the U.S., but even adjusting for population, the Japanese death rate is a mere 2% of America’s.
This comes despite Japan having no lockdown, still-active subways, and many businesses that have remained open—reportedly including karaoke bars, although Japanese citizens and industries are practicing social distancing where they can. Nor have the Japanese broadly embraced contact tracing, a practice by which health authorities identify someone who has been infected and then attempt to identify everyone that person might have interacted with—and potentially infected. So how does Japan do it?
“One reason is that nearly everyone there is wearing a mask,” said De Kai, an American computer scientist with joint appointments at UC Berkeley’s International Computer Science Institute and at the Hong Kong University of Science and Technology. He is also the chief architect of an in-depth study, set to be released in the coming days, that suggests that every one of us should be wearing a mask—whether surgical or homemade, scarf or bandana—like they do in Japan and other countries, mostly in East Asia. This formula applies to President Donald Trump and Vice President Mike Pence (occasional mask refuseniks) as well as every other official who routinely interacts with people in public settings. Among the findings of their research paper, which the team plans to submit to a major journal: If 80% of a closed population were to don a mask, COVID-19 infection rates would statistically drop to approximately one twelfth the number of infections—compared to a live-virus population in which no one wore masks.
The mask debate, of course, has been raging for weeks in the States and globally. Pro-maskers assert that the widespread use of face coverings can diminish the spread of COVID-19. Some anti-maskers, including various politicians and public health officials, have insisted that there is no proof of the efficacy of face guards. According to some activists, a blanket mask mandate places a limit on individual liberty and even one’s right to free speech. (Pro-mask advocates are fighting back with #masks4all and #wearafuckingmask Twitter campaigns).
Representatives of the World Health Organization have also been sounding rather anti-mask, fretting that many people won’t wear masks properly, thereby risking infection, or that masks will give people a false sense of security and encourage risky behavior, such as partying up close and personal—none of which seems to have played out, as far as we know, in Japan or Hong Kong or other mask-wearing places. Adding to the brouhaha has been the shortage of medical masks for doctors, nurses, bus drivers, and the guy who delivers burritos to your door.
The muddle over masks is what drove Berkeley’s De Kai to drop everything two months ago and help convene an ad hoc team of scientists and academics: a physician from London, a bioinformaticist from Cambridge, an economist from Paris, and a sociologist and population-dynamics expert from Finland.
“I felt like this was pretty urgent,” said De Kai, who was born in St. Louis, and is the son of immigrants from China. “I saw the country where I grew up, where my family lives [now mostly in the Bay Area], about to face this pandemic without knowing much about something as simple as wearing a mask to protect themselves and others.” In part, this comes from a cultural difference between East Asia, where masks have been routinely worn for decades to fend off pollution and germs, and other parts of the world. This includes the U.S., where people are unaccustomed to wearing masks, and, in the past, have sometimes been insensitive, even stigmatizing East Asians, many of whom had chosen to wear them in public prior to the pandemic, and had continued the practice in the aftermath of the SARS and MERS outbreaks. (In part, this habit was meant to show other people that they were concerned about transmitting the disease—something we in the West would do well to emulate.)
De Kai’s solution, along with his team, was to build a computer forecasting model they call the masksim simulator. This allowed them to create scenarios of populations like those in Japan (that generally wear masks) and others (that generally don’t), and to compare what happens to infection rates over time. Masksim takes sophisticated programming used by epidemiologists to track outbreaks and pathogens like COVID-19, Ebola, and SARS, and blended this with other models that are used in artificial intelligence to take into account the role of chance, in this case the randomness and unpredictability, of human behavior—for instance, when a person who is infected decides to go to a beach. De Kai’s team have also added some original programming that takes into account mask-specific criteria, such as how effective certain masks are at blocking the invisible micro-droplets of moisture that spray out of our mouths when we exhale or speak, or our noses when we sneeze, which scientists believe are significant vectors for spreading the coronavirus.
Along with the masksim site, the team is also releasing a study that describes their model in detail as well as their contention that masksim’s forecasts support a growing body of pro-mask evidence. “What’s most important about wearing masks right now,” said Guy-Philippe Goldstein, an economist, cybersecurity expert, and lecturer at the Ecole de Guerre Economique in Paris—and a masksim collaborator, “is that it works, along with social distancing, to flatten the curve of infections as we wait for treatments and vaccines to be developed—while also allowing people to go out and some businesses to reopen.”
While all models have limitations and are only as good as their assumptions, this one is “a very thorough model and well done,” said William Schaffner, an infectious disease specialist at Vanderbilt University, who reviewed the De Kai team’s paper. “It supports a notion that I advocate along with most other infectious disease experts: that masks are very, very important.” Jeremy Howard, founding researcher at and a distinguished research scientist at the University of San Francisco, also assessed the paper. “It’s almost overkill how careful they were with this modeling,” said Howard, who also coauthored and spearheaded a study last month (recently submitted to the journal PNAS) that reviewed dozens of papers assessing the effectiveness of masks.
During a screen-share Zoom from his home office in Hong Kong, De Kai, who has not had to shelter in place (“because nearly everyone in here wears masks”), explained to me how the model works.

So instead of killing 670,000 people all we need to do is get 80% of the population to wear a mask. Simple, but not easy. You would have thought everyone would buy into this model, given the alternative. But the people I engaged with seem to think that wearing masks is as bad as, if not worse than, the hard lockdown we have experienced in South Africa.
I can't find any logic to back up this claim, or any scientific evidence either. There are plenty of wild theories about how the data is being manipulated and how the testing isn't being done right. I have tried to accommodate some of these theories in the way I arrived at the number of dead people, but they refuse to listen. Anyone would think they were sociopaths. I think they are just out of touch with the meaning of big numbers. Or they are so fixed in their position that no amount of new information will change their minds.

Update Friday 15 May: There are a total of 3,000 ICU beds in private and public hospitals. The President mentioned an additional 25,000 beds have been added, but not ICU level of care. If every death came out of ICU, then the ICU would be 223 times over-subscribed if they all happened at once. Assuming an ICU patient dies after 1 week, we cannot have more than 428 people dying every day in ICU (3,000 divided by 7). Unless the "herd immunity" took over 4 years to be achieved, the hospitals would be swamped. Any way you look at it is disastrous.
Another argument I keep seeing (usually by the same people who think herd immunity is a good idea) is that CV is "no worse than the flu". Roughly 5% of the deaths every year in South Africa are diagnosed as flu and/or pneumonia, which would mean that 26,390 people die of flu or pneumonia. Of course that compares quite well (25x) with 670,000 deaths. And that's including all the pneumonia deaths as well. In the USA, the ratio of flu deaths to pneumonia deaths is 1:13.
Let's recalculate the deaths assuming that the 4.41% death rate is too high, because of inadequate testing, so the number of "resolved cases" is in fact higher. That would mean that symptomatic people who recovered were never tested or treated. We have already accounted for asymptomatic cases. Also, let's assume that the doctors are getting better at treatment, and that by early use of Hydroxychloroquine, Azythromycin and Zinc they save additional lives. Let's assume only 7.5% of the TB and Diabetes patients die, and the death rate for the rest is 2% instead of 4.41%. And the CV only impacts 7.5% of the total deaths. Total additional deaths is 195,315. If you think that is OK then you think that all the road deaths for the last 8 years combined is an acceptable number too. I can't help you.

Update Monday 1 June: Of course there are some people who think it is fashionable to be controversial and mock or discourage people from wearing face masks, without giving the implications much serious thought. Here is a classic example:
Tasteless in my opinion. Especially given the selfishness it demonstrates. I guess younger people feel invincible, even though they spread the disease even more so than older people.

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