By J.B. Handley
Why did politicians ever lockdown society in the first place? Can we all agree that the stated purpose was to “flatten the curve” so our hospital system could handle the inevitable COVID-19 patients who needed care? At that point, at least, back in early March, people were behaving rationally. They accepted that you can’t eradicate a virus, so let’s postpone things enough to handle it.
The fact is, we have done that, and so much more.
The headlines are filled with dire warnings of a “second wave” and trigger-happy U.S. governors are rolling back regulations to try to stem the tide of new cases. But, is any of it actually true and should we all be worried? No, it’s not a second wave.
The COVID-19 virus is on its final legs, and while I have filled this post with graphs to prove everything I just said, this is really the only graph you need to see, it’s the CDC’s data, over time, of deaths from COVID-19 here in the U.S., and the trend line is unmistakable:
If virologists were driving policy about COVID-19 rather than public health officials, we’d all be Sweden right now, which means life would effectively be back to normal. The only thing our lockdowns have done at this point is prolong the agony a little bit, and encouraged governors to make up more useless rules.
Sweden’s health minister understood that the only chance to beat COVID-19 was to get the Swedish population to a herd immunity threshold against COVID-19, and that’s exactly what they have done, so let me start there.
The Herd Immunity Threshold (HIT) for COVID-19 is between 10-20%
This fact gets less press than any other. Most people understand the basic concept of herd immunity and the math behind it. In the early days, some public health officials speculated that COVID-19’s HIT was 70%. Obviously, the difference between a HIT of 70% and a HIT of 10-20% is dramatic, and the lower the HIT, the quicker a virus will burn out as it loses the ability to infect more people, which is exactly what COVID-19 is doing everywhere, including the U.S, which is why the death curve above looks the way it does.
Scientists from Oxford, Virginia Tech, and the Liverpool School of Tropical Medicine, all recently explained the HIT of COVID-19 in this paper:
“We searched the literature for estimates of individual variation in propensity to acquire or transmit COVID-19 or other infectious diseases and overlaid the findings as vertical lines in Figure 3. Most CV estimates are comprised between 2 and 4, a range where naturally acquired immunity to SARS-CoV-2 may place populations over the herd immunity threshold once as few as 10-20% of its individuals become immune.”
Calculations from this study of data in Stockholm showed a HIT of 17%, and if you really love data check out this great essay by Brown Professor Dr. Andrew Bostom titled, COVID-19 ‘herd immunity’ without vaccination? Teaching modern vaccine dogma old tricks. I’m going to share his summary with you, because it’s so good:
“Naturally acquired herd immunity to COVID-19 combined with earnest protection of the vulnerable elderly – especially nursing home and assisted living facility residents — is an eminently reasonable and practical alternative to the dubious panacea of mass lockdowns and other measures against the virus.”
This strategy was successfully implemented in Malmo, Sweden, which had few COVID-19 deaths by assiduously protecting its elder care homes, while “schools remained open, residents carried on drinking in bars and cafes, and the doors of hairdressers and gyms were open throughout.”
One of the most vocal members of the scientific community discussing COVID-19’s HIT is Stanford’s Nobel-laureate Dr. Michael Levitt.
Back on May 4, he gave a great interview to the Stanford Daily where he advocated for Sweden’s approach of letting COVID-19 spread naturally through the community until you arrive at HIT. He stated:
“If Sweden stops at about 5,000 or 6,000 deaths, we will know that they’ve reached herd immunity, and we didn’t need to do any kind of lockdown. My own feeling is that it will probably stop because of herd immunity. COVID is serious, it’s at least as serious flu. But it’s not going to destroy humanity as some people thought.”
Guess what? That’s exactly what happened. As of today, 7 weeks after his prediction, Sweden has 5,280 deaths. Deaths in Sweden peaked when the HIT was halfway to its peak (roughly 7.3%) and by the time the virus hit 14% it was nearly extinguished.
How could Dr. Levitt have predicted the death range for Sweden so perfectly 7 weeks ago? Because he had a pretty solid idea of what the HIT would be. (If you’d like to further geek-out on HIT, check out: Why herd immunity to COVID-19 is reached much earlier than thought.)
I absolutely love Dr. Levitt (and as a Stanford alum, so proud he is a Stanford professor) and am thrilled with his brand-new paper, released today, Predicting the Trajectory of Any COVID19 Epidemic From the Best Straight Line.
By the way, as a quick aside, and something else the press won’t touch: COVID-19 is a coronavirus, and we have all been exposed to many coronaviruses during our lives (like the common cold).
Guess what? Scientists are now showing evidence that up to 81% of us can mount a strong response to COVID-19 without having been exposed to it before:
“Cross-reactive SARS-CoV-2 T-cell epitopes revealed preexisting T-cell responses in 81% of unexposed individuals, and validation of similarity to common cold human coronaviruses provided a functional basis for postulated heterologous immunity.”
This alone could explain why the HIT is so much lower for COVID-19 than some scientists thought originally, when the number being talked about was closer to 70%.
Many of us have always been immune!
If that’s not enough for you, a similar study from Sweden was just released and shows that “roughly twice as many people have developed T-cell immunity compared with those who we can detect antibodies in.”
(We kind of knew this from the data on the Diamond Princess when only 17% of the people on board tested positive, despite an ideal environment for mass spread, implying 83% of the people were somehow protected from the new virus.)
Quick Update: This article came out one day after I wrote mine, and validated everything I just said, except the author is wrong about COVID-19’s HIT, it’s 10-20%, not 60%, which is even better news:
“However, it does provide a possible explanation for why the Covid-19 epidemic seems to have died away in many places once it had infected around 20 per cent of the local population (as judged by the presence of antibodies). If people are developing some kind of immunity to Covid-19 via their T cells then it could mean that a far higher percentage of the population has been exposed to Covid-19 than previously thought. Antibodies and T cells combined, it is conceivable that some places such as London or New York are already at or near the 60 per cent infection level required to achieve herd immunity.”
Back to the death rates over time. We actually have our own Sweden here in the U.S. It’s called New York City. In our case, we accidentally created a Sweden scenario, in that we took our medicine quickly, because:
- New York locked down so late that the curve was not flattened
- They have the highest population density in the U.S. in New York City
- The public health officials and governor there made the bone-headed decision to send COVID-positive nursing home residents back to their nursing home, accelerating deaths of the most vulnerable.
What’s their death curve look like today? In this case, I borrowed the graph from the NYC public health website:
Hmm…notice anything about the chart or its slope? The reason deaths from COVID-19 are dwindling down to nothing isn’t because Governor Cuomo is a policy genius (in fact, he likely created more unnecessary deaths), it’s because the virus — like every virus in the history of mankind — is running out of people to infect.
The virus has a HIT of 10-20% and 70% of people are likely naturally immune. Hosts are in short supply! That’s what viruses do, and wait until you see what New York’s likely HIT is today.
We can get a crude, but helpful proxy for whether or not a state (or region) has achieved their own Herd Immunity Threshold if we know the following things: the size of the population, the number of deaths from COVID-19, and COVID-19’s IFR, or Infection Fatality Rate.
In my first blog post late last month, LOCKDOWN LUNACY: the thinking person’s guide, I discussed Infection Fatality Rate in detail, so I am just going to give a very quick summary here.
Stanford’s Dr. John Ioannidis published a meta-analysis (because so many IFR studies have been done around the world in April and early May) where he analyzed twelve separate IFR studies and his conclusion lays out the likely IFR for COVID-19:
The infection fatality rate (IFR), the probability of dying for a person who is infected, is one of the most critical and most contested features of the coronavirus disease 2019 (COVID-19) pandemic. The expected total mortality burden of COVID-19 is directly related to the IFR. Moreover, justification for various non-pharmacological public health interventions depends crucially on the IFR.
Some aggressive interventions that potentially induce also more pronounced collateral harms1 may be considered appropriate, if IFR is high. Conversely, the same measures may fall short of acceptable risk-benefit thresholds, if the IFR is low…Interestingly, despite their differences in design, execution, and analysis, most studies provide IFR point estimates that are within a relatively narrow range.
Seven of the 12 inferred IFRs are in the range 0.07 to 0.20 (corrected IFR of 0.06 to 0.16) which are similar to IFR values of seasonal influenza. Three values are modestly higher (corrected IFR of 0.25-0.40 in Gangelt, Geneva, and Wuhan) and two are modestly lower than this range (corrected IFR of 0.02-0.03 in Kobe and Oise).
The data on IFR has now been replicated so many times that our own Centers for Disease Control announced that their “best estimate” showed an IFR below 0.3%.
In this article on the CDC’s new data, they also highlighted how the cascading declines in IFR has removed all the fears of doomsday:
“That ‘best estimate’ scenario also assumes that 35 percent of infections are asymptomatic, meaning the total number of infections is more than 50 percent larger than the number of symptomatic cases. It therefore implies that the IFR is between 0.2 percent and 0.3 percent.
“By contrast, the projections that the CDC made in March, which predicted that as many as 1.7 million Americans could die from COVID-19 without intervention, assumed an IFR of 0.8 percent. Around the same time, researchers at Imperial College produced a worst-case scenario in which 2.2 million Americans died, based on an IFR of 0.9 percent.”
In order to be as bullet-proof as possible, and because the IFR is an important part of the math I will do right now, I’ve decided to pick a simple and defensible number, the final number pegged by the CDC for COVID-19’s IFR: 0.26%.
(As an aside, if we’d known this 3 months ago, no one in the public health world would have panicked. It’s a bad flu, and the rates for younger people are dramatically below 0.26% and approaching zero for children.)
Now that you understand COVID’s IFR and the likely HIT, it’s much easier to talk about the second wave, the data, and the implications. Here’s the deal:
“Yes, certain states are having an uptick in three measurements: COVID-19 tests administered, positive COVID-19 tests, and hospitalizations. All three of these measurements are dubious. Hopefully, some of the rise in cases is real, because then the U.S. will arrive at Herd Immunity Threshold (“HIT”), which has been slightly delayed by lockdowns, sooner. Based on the “death curve” in the U.S., we are very close to being done.”
Take population, COVID Deaths, and IFR to find HIT
C’mon stay with me! This math is basic, junior high level stuff. And, it’s going to give us the most important, but very crude, number we need to understand all this second wave nonsense: the approximate HIT already attained by state and by the United States.
If you know how many people have died from COVID-19 in any one region, you can quickly calculate how many people have had COVID-19 in that same region. All you do is divide deaths by the IFR. Let’s use NY as the example.
As of today, there have been 31,137 deaths from COVID-19. Take 31,137/.0026, you get 11,975,969 people infected with COVID-19. Take those 11 million people divided by New York’s population of 19.45 million, you get a HIT of…65%.
(Data geek comment: New York’s HIT is clearly OVER-stated, because total deaths drives HIT, and NY has a much higher rate of nursing home deaths due to bad policy.)
Huge disclaimer: This math is crude, but it’s also directionally accurate, and the comparisons between states helps explain what’s going on. Importantly, the HIT required to snuff out the virus in any one region could be lower than Sweden’s number of 17%, for a million reasons, most notably better medical knowledge today than a few months ago about how to keep a vulnerable person alive.
Still, just look at this table I created using the math above:
Notice anything? New York is well past Herd Immunity Threshold (as is New Jersey), the southern states in the news today are below the implied HIT, while the U.S. overall is nearly there with 15%. This is why the death curve from the CDC (and NYC!) that I opened this blog post with looks the way it looks: we are basically done with the virus. Just like Sweden. Oh, and Italy:
Quick update: Mount Sinai doctors just released a study showing a seroprevalence study of a random sample of 5,000 New Yorkers, it states that “by the week ending April 19, the seroprevalence in the screening group reached 19.3%.”
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Credit: Off Guardian