Quote:
Originally Posted by pip08456
There is no chance of antibodies preventing infection and that applies to any Vaccine. Antibodies play no part in preventing infection of the person vaccinated.
I am sure jonbxx can explain it better than me but here goes.
The immune system is very complicated but has a very good memory, there is no such thing as an antibody per se, antibodies are a combination of T cell, B cells (and others) which fight an infection.
So, if a vaccinated person never gets infected then the immune system plays no part.
However, if a vaccinated person gets infected then the combination of T cells etc are already active and know what to do to fight it. This leads to reduced severity, hospitalisation and death because the immune system doesn't have to remember what worked as the solution is still active. This reduces the reaction time before the bodies defenses go into action, they are already there. This is the reason for the booster shots, they keep the solution the immune system worked out active.
So, if you've digested that then let's take it a little further.
I get infected bya non-vaccinated person so the viral load passed on to me is high.
My immune system is prepared to fight back immediately (it doesn't need to refer back to memory) because I'm fully vaccinated and boosted.
Now even though I'm "protected" my immune system gets overloaded due to the viral load and I start feeling ill or "out of sorts" until my immune system brings in the reinforcements it needs. However I may not realise I have contracted covid due to the symptoms.
Then I go and meet up with Seph for whatever, my viral load should be less than the unvaccinated person who passed (perhaps asyptomatic) to me albeit unknowingly.
Now Seph has caught it form me but the viral load is less so his immune system can deal with it easily and wipes it out quickly in his system and no viral load to transmit because my viral load was much less and Seph's immune system wasn't overwhelmed.
This applies to every single vaccine ever produced. There is not one that prevents infection.
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Hello!
You are right in that the immune system is horribly complicated and there are still new discoveries being made on the regulation of the immune system...
There are two broad parts of the immune system - the innate and acquired. The innate immune system is you first defence against infection. Once infected, all kinds of signals are produced saying 'something is not right here' and then all hell breaks loose. There will be inflammation and activation of cells which 'eat' microbes and kill virus infected cells. Infected cells will display virus proteins on their surface to mark themselves as infected. The current COVID vaccines produce viral proteins inside cells which are displayed on the cell surface.
Alongside the immediate fight, the acquired immune system will be activated during this process. T cells which recognise the viral proteins will be generated (T cells are the watchmen of the immune system and some have direct cell killing functions) B cells which make antibodies will also be stimulated to find B cells which make good antibodies against the infection (there a mini evolution which happens here)
If you are not vaccinated or previously infected, the innate system kicks in quick (think how quickly you got the typical vaccine side effects, that's your innate immune system kicking off) The acquired immune system takes a little longer to kick in as there is this evolution of finding the best T cells and antibodies. This can take a week to 10 days to really get going. The acquired system is super specific and has the advantage with viral infections of antibodies stopping virus entering cells
After your infection dies down, you will be left with a few antibodies if your blood but will also have T cells and B cells that will recognise the virus and viral infections and will kick in very quickly on a subsequent infection. Bearing in mind that virus needs to go in to cells to reproduce, the only way you can prevent infection is to recognise and stop the virus from getting in to cells. Antibodies which bind parts of the SARS-COV-2 spike protein are very good for this. These neutralising antibodies are like gold dust as they not only help mop up free virus but also stop infection. This was why there was a big panic about variants escaping the vaccines a while back