Immune or not? seems simple. Apparently it's not

Right, but I was asking about during those 10 years. But NVM, apparently according to the CDC, it seems to be pretty close to perfect protection.

https://www.cdc.gov/vaccines/vpd/dtap-tdap-td/hcp/about-vaccine.html#:~:text=Immunogenicity%20and%20Vaccine%20Efficacy&text=A%20complete%20vaccine%20series%20has,for%20children%20younger%20than%207.

I was just thinking earlier that you can’t really get “herd immunity” from something that you don’t actually catch from others.

It matters to the community if you get the COVID vaccine. Other than shared medical costs and use of medical resources, no one else benefits from you getting the tetanus shot.

In my neighborhood, there’s an effort to stop the sharing of rusty nails. You can get one free clean nail from the local hardware store each week of you promise not to let others step on it. We’re all in this together.

I’ve been trying to drink more “Rusty Nails”. Both due to the Covid crisis, but also in honour of Doonesbury’s “Duke”. Just doing my part.

If you came to the ER with a dirty wound and were not quite sure you had had a tetanus shot within five years you would likely be offered one even though tetanus is uncommon and the boosters work well.

I chuckled. Good one!

The polio vaccine provides sterilizing immunity, meaning that once you’ve had the vaccine you can no longer get polio. You are 100% immune.

What ? Totally wrong disease to use as an example of “sterilizing immunity”.

Well there are two types of polio vaccine.
Salk, and Sabine.

Sabine is attenutated virus . Which means that you actually get a polio infection from it, but its a very weak form of it. But there is recombination happenning, and theres a tiny tiny chance of it regaining its strength. recently the use of sabine has created more detected cases of polio than wild cases . This is taken orally as it causes the infection in the intestines, where all polio infections start.

Salk is an injection and it just prevents the neurological damage that polio causes.
You can still get the polio in your intestines, because the injection hasn’t trained your immune system to fight off the intestinal infection.

Tetanus, and pertussis and most vaccines against bacteria are equally only to prevent the serious illness, not the infection.

BCG for TB trains your body to fight TB in your ordinary flesh, eg skin and muscle… but its not so good at preventing infection in lining of your lung.

The myth that the covid19 is going to be similar to influenza can be explained as a myth.
The SARS2 virus is only attacking the ACE2 receptor. This receptor requires a very precise key , the spike protein is that key. It can’t really evolve to attack other receptors in humans, as a chance to give it a long shot at attacking another receptor should totally reduce its chance of entering via human ACE2… it could evolve by jumping species, where maybe the receptor is slightly different and the species jumping provided the stepping stones.

Influenza enters cells using generic weaknesses in the cell membrane structures, so it has less trouble evolving. If it randomly evolves to attack a new site at some tiny chance, its not lost much chance to attack the old sites. So it smoothly refines a new protein for entering the human cell… So statements like “Covid19 cannot be eradicated” should be treated as myth , it seems clear that the entry via the ACE2 receptor is why covid19 is a deadly common cold… its not the payload , its the spike protein… which can’t evolve. So the SARS2 with the ACE2 receptor attack can be wiped out, as was the SARS 1 …

A really simple way of understanding any immunity generation is that it is all about giving you a head start. Your immune system and any infection are in a race. Initially the infection has the head start. The pathogen starts to reproduce exponentially inside you. At some point the population of the pathogen reaches a point where it starts to make you ill. For bad pathogens this can lead to bad outcomes up to and including death. But your innate immune system enters the battle early recognising any individual pathogen as something that isn’t you and killing it. Usually there isn’t enough of the pathogen around, or it reproduces slowly enough that it is mopped up before it can get far enough down the path of exponential growth. But if it does it will start to outrun the innate system. Then the next level of the system kicks in as bits of killed pathogen are used to train customised killer cells that go looking, not for things that aren’t you, but things that are the pathogen. And you body swings significant resources behind this task. So much so that just this effort will make you feel ill, on top of the ills the pathogen inflicts. The task is to outrun the exponential growth of the pathogen and wipe it out. Usually the body wins. If it can’t win this race things get grim. Much treatment of infection is all about giving the immune system more time. Antibiotics kill bacteria and thus effectively reduce the R factor on its exponential. Otherwise we just do what we can to keep you alive longer and hope it is enough to allow the immune system to close the gap and get ahead in the race. Once it is ahead things can get mopped up pretty quickly.
The body will reduce the effort creating the response and just have a capability ticking over ready to ramp up again. This sticks around for a while after the infection has passed. Which is good. The next time a load of pathogen hits you the system does not have to wait for the early steps in the chain. It already knows what the pathogen looks like and knows how to make antibodies, so the infecting pathogen usually has no chance. It gets mopped up well before it gets far down it’s exponential growth path.
Long term, the body writes copies of the information needed to create the antibodies onto other cells, which act as a long term archive of past successful responses. So again it can avoid the early stages of system detection and training needed to mound a response.
Immunisation is a way of triggering the part of the immune response to create this trained response. Minimally it seeks to get the body ticking over with the capacity to ramp up creation of the needed antibodies. A next level win is when the memory cells also retain information needed to restart production. The success seen here is what determines the need for booster shots in the future.

In the end the point is to get your body a head start. How much of a head start you have is a big determinant of how far a new infection can get. If you are totally primed to mount a wipe out response the next time you encounter the pathogen it will be wiped out before there is any evidence of infection. But it is a continuum. A really big dose of infecting pathogen, or a slower ramp up speed from the immune system may give the pathogen time to get a slight foothold before the cavalry arrives. Perhaps the worst case for the community is you become infectious but asymptomatic, so they worry about this. But there is always the chance you become ill again. However the cavalry is on its way, just a bit late. Chances are very good that it will mop up the infection long before you get really ill.
Successful immunisation programs mostly don’t wipe out a disease. That is really hard. But across the community you get to the point that nobody dies or becomes critically sick. That is the current expectation.

The other point to remember - the vaccine is about breaking the infection path. You get the disease from others who have it, and leave virus particles in droplets in the air, aerosols, and on surfaces. The more people you encounter who have the disease, the more likely you too will get it. “Exponential growth” is an issue outside the single individual too.

By being vaccinated, the less likely you will get sick - or sick enough to pass it on - should you encounter it. The more people not passing it on, the less likely anyone - vaccinated or not - will encounter an infection opportunity, and now the situation is we hope herd immunity, or exponential shrinkage.

A 5% chance to catch the disease is a better chance if you are not 100% likely to encounter an infectious person today.

Oops! I messed that up didn’t I?