You are repeating this but don't understand it.
Understanding the exponential function of mathematics is key to understanding pandemic pathogen transmission. The R value from this function (the viral transmission rate) determines whether a pandemic expands or dwindles away.
For example, if R = 2, meaning that on average, each infected person goes on to infect two further people, then the number of infected cases will follow this exponential growth pattern:
1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, etc
There are plenty of tutorials online about the exponential function, and how it is involved in multiple real-world circumstances, like bacterial growth, and compound interest on investments.
Strictly speaking, though, pandemics are not determined by exponential functions, but by another similar mathematical function called the sigmoid function. Though the numerical results of the exponential and sigmoid functions are closely tally when the number of infected and immune people is much lower than the total population. So reading about the exponential function gives a good insight into pandemic dynamics.
I think you misunderstand herd immunity. Herd immunity doesn't mean the virus ceases to exist. It means it slows it down enough to prevent rapid spread.
Obviously herd immunity means that virus transmission (the R number) is reduced, due to people becoming immune to catching the virus, thus inhibiting viral spread. I've said this in my posts.
You seem to be stating what you think I wrote, rather than what I actually wrote.
You should absolutely NOT think like a mathematician and reduce it to an overly simplistic model with 1 variable because it leads to misunderstanding of things like herd immunity as seen above.
The art of mathematics and science it the ability to figure out what real-world parameters need to be incorporated into a model, and which can been left out, because they do not have any significant bearing on the system. This is ability part of the training in science.
If your model leaves out important factors, then it will not produce accurate results. If it incorporates unimportant factors, then it may become unnecessarily complicated. The art of mathematics and science is working out which factors need to be incorporated, and which can be safely left out.
The reason why you don't understand the problem is:
1. You view immunity as binary state instead of the multi-layered complex defense system it really is.
2. You view the pandemic phenomenon as a single variable the reproduction rate.
3. You don't cross-check with the real world.
You can't model or understand a pandemic based on this alone. This is like economists who think they can model human behavior with a simple equation and then usually fail to make accurate real world predictions.
Again, you seem to be stating what you think I wrote, rather than what I actually wrote. You are presumptuously putting words into my mouth, and then arguing with those words, not with what I actually said.
Where did I state that immunity is a binary state?
Where did I state that the pandemic is governed by a single variable?
There are countless factors involved in the pandemic. However, any epidemiologists will tell you that are far as pandemic expansion or contraction are concerned, it is the R number which measures that. The R number is the sum result of all the countless factors.
Similarly, there are countless factors involved in the economy, but any economist will tell you that the expansion or contraction of gross domestic product (GDP) gives an overall measurement of the state of the economy.
After several waves the disease seems to be weaker, people who are re-infected get less sick. We don't hear about lack of oxygen anymore. Most people I know seem to have moved on, I don't hear from people get seriously ill anymore.
The pandemic has not gone away, but governments and the media are not publicising the deaths as much, presumably because they want people to go back to work, otherwise the economy will suffer.
The UK Worldometer shows that for the last year and a half, there have been around 100 deaths per day. It goes up and down a bit, sometimes 150 deaths a day, sometimes 50, but 100 is about the average. That trend continues today, with no sign of abating so far.
Over 90% of people in the UK have caught COVID at least once. So clearly herd immunity is not extinguishing the pandemic.
At the peak of the waves, before we had the vaccines, there were around 1000 deaths per day in the UK. But vaccination has helped bring this figure down. Also, perhaps this figure went down because many of the most vulnerable people have now died, so the people who are left now are the tougher ones.
I hope that the repeated use of mRNA booster vaccines will not lead to immune tolerance, otherwise the death rate may rise.
In terms of the long term outcomes of this COVID pandemic, one piece of good news is that in populated areas (like most modern cities), viruses tend to evolve into more benign forms.
We have seen this already with omicron, which is more benign but more transmissible than delta.
It's actually in the virus's interest to become more benign in populated areas. This is because the virus's primary goal is to survive and transmit. If a virus is too fierce, and kills or incapacitates people it infects, then its chances of transmission may actually be reduced, because those infected people will be too ill at home, or dead, and so not participating in social environments where the virus has a chance of spreading to other people.
Whereas if the virus evolves to produce a milder infection, then infected people may still go to work and socialise, which then gives the virus many more opportunities to transmit to others. This is why in populated regions, viruses tend to evolve to become more benign.
So we may see increasingly more benign strains of COVID appearing, and taking over previous less benign strains.
Did you know that all coronaviruses that exist today and that infect us frequently were once pandemic viruses?
I did not know that, but it certainly makes sense. As detailed above, when viruses first hit human populations, they can be very nasty, but may evolve into more benign forms in populated regions over time.
Syphilis was such a severe infection when it first hit Europe, that the flesh would literally drop off the limbs of infected people. But over time, it evolved into more benign forms.
The chances of developing such a vaccine are rather low. It will likely not happen. The virus will be with us just like the spanish flu and aother corona and influenza pandemic viruses are still with us.
Researchers have been looking at developing mucosal vaccines for COVID. Though there is a lack of funding.
Mucosal vaccines train the mucosal immune system (the immune system residing on the mucous membranes), rather than systemic immune system which is trained by injected vaccines.
Mucosal immunity uses different antibodies, IgA antibodies rather than the IgM and IgG antibodies of systemic immunity.
The advantage of training mucosal immunity is that when a respiratory virus like COVID first hits our bodies, it does so by landing on one of our mucous membranes (oral, nasal or throat mucous membranes). If the virus encounters a robust immune response on these mucous membranes, it may be killed there and then, without ever getting into the bloodstream. So you may be able to completely prevent an infection if you have enhanced mucosal immunity.
Mucosal vaccines are also good for those who are needle phobic, since they are administered orally or via a nasal spray.
This is an article on COVID mucosal vaccines.
Edited by Hip, 23 January 2023 - 05:37 PM.
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