The numbers have been following the mathematical models.
If you really listen to the experts, particularly people who have been constrained in the White House like Tony Fauci, you hear a consistent message. They all expect that upwards of 50 million people in this country will eventually be “infected”. I think that that number is actually low, but excludes a very large number, maybe as much as an additional 100 million people, whose infections were subclinical, or so mild as to not be tabulated. Again, listening to them you hear that the efforts at personal isolation are NOT intended to reduce the total number of infections, but rather to spread them out over a longer period of time so that the health system is not overwhelmed and that we might have some time to develop either chemical treatments that can lessen the mortality, vaccines or other strategies.
If, however, the number is correct, and if, the death rate is as low as 1%, 50 million people infected will result in 500,000 deaths.
I have done my own, uneducated model using the data available from Johns Hopkins on documented infections and deaths. The numbers are a little difficult to analyze for a number of reasons, but there are two particular reasons that are important.
The first constraint is that we know that the “documented infections” only catches a fraction of the actual infections. It has been assumed that as much as 80% of people who are infected have mild or no symptoms. There is also a fraction of people who, although quite ill, don’t present at hospitals and either recover or die and are not included in these statistics. So, trying to estimate the mortality rate by looking at the simple fraction of DEATHS/CASES is difficult because the number of cases is probably very underestimated.
The second constraint is even more important. If a person gets infected (we can call that Day-0), it takes, on average about 5 days before the first symptoms appear (Day-5). It takes another 5 days before the symptoms become severe enough to impel a trip to the hospital (Day-10). This is the day on which the “documented cases” are recorded. As often mentioned, that number really is a reflection of the number of infections that occurred on Day-0.
When that patient enters the hospital, they are treated and many recover, but some become much more ill and are maintained on ventilators for as many as 4 weeks. We can use an average time to death of about 15 days; so the patient dies on Day-25. And there is the constraint. On a particular day the reported documented cases capture a picture that is 10 days old, while the deaths recorded that day reflect a picture that is already 25 days old.
What this means is that the ACTUAL mortality rate is more accurately determined by the deaths on a particular day compared to the number of cases reported 15 days earlier, and we don’t see that data daily.
Using this model and looking back retrospectively at the reported data, I end up with a prediction of 450,000 deaths through this first round of COVID-19.
IF we had isolated everyone in the country in the way a number of communities and states are doing now, and IF we continue that for the next month or two, we can probably reduce that number by half or more. I think, when you hear Drs. Fauci and Birx speak about an optimistic 100,000 to 200,000 deaths if we do everything absolutely right, they are pretty much speaking to what I am seeing. Fortunately, they have mountains more data than me, better armed analysts and better computers.
THERE IS SOME GOOD NEWS IN THE INTERNATIONAL NUMBERS.
Sometimes we get misled by raw numbers: Italy has a lot of deaths, the US has the most infections, we are testing more than anyone else, Spain is seeing large growth, South Korea has a slower curve, etc.
The raw numbers are better understood if they are “normalized” for the population. So, looking at documented cases per million people of population or deaths per million is a far more valuable metric.
In this case the US looks a little bit better. (the data I have used is from the WHO and is as of March 30).
The US ranks #28 in documented cases per million population with 487 cases per million.
As a comparison:
Spain is #8 with 1,881 per million
Israel is #25 with 542 per million
Canada is #48 with 197 per million
South Korea is #51 with 188 per million and
China is # 95 with 57 per million.
When looking at deaths per million
The US ranks #22 with 9 deaths per million
Italy is #2 with 192 per million
South Korea is #34 with 3 per million
Israel is #39 with 2+ per million
Canada is #45 with 2+ per million and
China is #52 with 2+ per million
Looking at the data, what can we see?
China may or may not have been successful. There is debate over whether their reported low numbers are accurate. By confining the infection to a single province, the numbers for the country look much, much better. Ignoring this debate, the strictures that they placed on Wuhan and Hubei province were far stronger than anything we are currently doing or that we could most likely ever get away with; things such as enforcing curfews and travel, or placing people who had been in contact with an infected person in hotel rooms without permission to leave the room (sort of like Best Western Prisons).
Singapore and South Korea did great jobs because they began large-scale testing very quickly and therefore were better able to contain infections and infection-circles (those people who had been infected but were, as yet asymptomatic).
We are now testing at an increasing rate, and that is great. We are still limited in that we are restricting most tests to those people who are seriously ill. We do not have the volume to test enough asymptomatic people to truly understand the dynamics of the disease and its spread.
Here, we screen individuals to determine first, if they have significant disease with the symptoms that are reflective of this infection and not of other viral agents such as influenza, then we screen them as to whether they had been in contact with a foreign traveler, or a confirmed case. Then we test to determine if their illness is actually COVID-19. With limited tests, the rationale behind that is that we want to know that a hospital case is indeed COVID-19 so that the hospital can appropriately protect the healthcare workers.
A truly valuable study would look at the cohort of people surrounding an epicenter, but we can’t do that. As I have written, it is not the lack of test kits available, it is the lack of processing volume. If we can only process 30,000 tests a day, it doesn’t matter if there are 10 million test kits available. Combine that with the shortage of swabs and the problem is magnified. This is a work in progress and will improve over the next couple of months.
WILL THIS BE WITH US FOREVER?
The answer is both Yes and No. This virus will work its way through the world’s population.
A significant fraction of the population will be infected without symptoms, another fraction will have serious disease, and the remainder will go uninfected. This final group is particularly interesting, and I have seen little discussion about that topic. With any virus there is always a cohort of the population that remains uninfected.
There could be many reasons for this. Some of the people will have already acquired an immunity to the virus by previous infections with similar viruses. As I have discussed in the past, the immune system is not “intelligent”; it does not “see” a foreign thing like a virus and then “build” an antibody against it. Rather, the immune system is randomly creating unique antibodies constantly. When confronted with a new virus, an antibody that, by chance, happens to recognize that new antigen triggers its cell to reproduce and make lots of that antibody. For every individual, this means multiple different antibodies produced against that virus, and for different individuals, different catalogs of antibodies. If we understand that the antibodies that react with a virus are not “designed” by the body for that purpose, but are rather coincidental reactants, then we can understand that those same antibodies might also react with other closely related proteins. Depending on the response of a particular individual, prior exposure to similar viruses may have triggered immunity against the new virus. The reaction may be sufficient to stop infection, or it may be insufficient to protect from infectin, but strong enough to weaken the infection to the point at which it is far milder.
Another factor is the receptor on the cell surface, in this case the ACE2 protein. If you imagine the surface of a human cell, picture it not like a meadow with trees in which those trees are the ACE2 protein; instead picture it as an urban skyline. There are hundreds of different things on the cell surface. Some of them move around, bind to each other, unbind in the presence of factors in the blood, or change shape or function based on signals received from inside the cell. So, the virus has to be able to find that ACE2 receptor protein. If it gets stuck in the wrong place, or if the receptor is “protected” by another glycoprotein that is bound to it or something like another factor in the blood, it won’t get into the cell. A lot of those “buildings” on the cellular skyline are specific to individuals or groups of individuals. A simple form of this individuality that you are already familiar with is the ABO blood groupings on red blood cells. There are many, many types of individual distinctions on the proteins of a particular individual’s cells.
Finally, not every person’s ACE2 protein is necessarily identical to another person’s ACE2 protein.
There may be people that have very small changes in their ACE2 proteins, and it may be that those small changes (either in the amino acid sequence, or in the glycosylation (adding sugar moieties to molecules )) to those proteins result in a decreased ability of the virus to successfully attach or enter the cell.
So, yes the infection will continue, but if we are successful, the amount of illness will be controllable, treatable and manageable, at least until such time as treatments reducing mortality are identified.
I am hopeful that a vaccine can be developed; but this is not a given. There has not been a successful vaccine for any of the coronaviruses developed yet, nor one against e-bola or HIV even with significant effort expended. However, there is a tremendous amount of work going on and we can remain optimistic.
It is likely that we will see peaks and valleys in infection data as people begin to become complacent, desperate to get out of their houses (or away from their families), anxious to get back to work, see friends or visit relatives. Some will begin to loosen up after having been self-quarantined for 14 days and will be willing to risk visiting friends who also have been self-quarantined for 14 days. They will conclude that both sets of friends are now virus-free and therefore, there is no reason they shouldn’t have dinner together, play cards or watch a movie together. Unfortunately there is some evidence that people may remain symptom free for over 14 days, some people will be infected and contagious even though they have no symptoms, some evidence suggests that people who have recovered may still shed virus for weeks after there is no more evidence of disease. Please, remain self-quarantined for the immediate future.
WHEN CAN WE STOP QUARANTINING?
There is one and only one signal to stop. That signal is when the virus infection rate drops to or below 1. At that time the healthcare system will be able to detect, isolate, contact-trace and test individual cases. This is what must be done to stop the spread of the disease. It was done pretty well in Seattle and that is why Washington state is in front of the pandemic. If we begin to socially interact prior to that point we will see a new uptick in infections.
Finally, we have been phenomenally lucky in that our generation and the succeeding ones have never seen a “plague” before. Our parents did with Polio, our grandparents saw many including bubonic plague, typhus, diphtheria, etc., etc. Reservoirs of viruses exist in animals around the world and we can expect to see other viruses break out of those carriers and cause infections. We just need to adjust the way we approach these threats from the very beginning. Initial strong containment, testing and isolation policies need to be in place, along with serious, transparent and complete distribution of information. Political posturing will always fail - and fail in catastrophic ways.