Absolutely agree with everything Linus says here. But I'm almost equally concerned that there's an awful lot of people on the pro-science bandwagon who don't actually support science, but simply don't tolerate dissent or questioning, and that's unscientific and potentially harmful too. I scanned most of the Pfizer trial and was wondering why we expected the immunity after the vaccine to last longer than natural immun…
For simplicity's sake, your immune system has two main things of concern here: antibodies and memory cells (B and T). Antibodies are the short-term "find and kill invaders" proteins. They're looking for a particular antigen to attack and do so well, but they don't last very long. Memory cells are basically blueprints which stick around for much longer than the antibodies (some studies indicate for decades), so that if your body ever encounters those same antigens again it recognizes them much faster and starts pumping out the antibodies much faster as well.
So, why would a mRNA vaccine result in better long-term protection than COVID-19 itself? Well, the thinking here is that because an mRNA vaccine in this case only results in the creation of the singular spike protein, the antibodies created to fight off the invader are very focused, as they're only ever going to be looking for that one protein. In the same way, the memory cells your body creates will also be very focused. Your immune system post-vaccine is therefore very well adapted at targeting that particular protein/antigen (could be an amino acid that is part of the protein).
Meanwhile an immune system fighting off actual COVID-19 might be creating antibodies and memory cells that are targeting slightly different antigens, as the overall coronavirus has 29 different proteins your immune system could be looking at to find antigens. This could result in a little bit more "overlap". e.g. You have two antibodies each keyed to a different antigen. They both find the same sars-cov-2 target and bind to their two respective sites. They're now doing "redundant work". Additionally, any antibody which is targeting an antigen that is not the spike protein is probably going to be less effective (the spike protein was targeted for the vaccine because it accounts for most of the outer surface area of the virus, which obviously makes it the best target for antibodies which must "bind" to something).
tl;dr: mRNA vaccines might be more effective than natural immunity because they are creating tools which attack only the most targetable of sars-cov-2's proteins – the spike protein. Natural immunity might give a more "diverse" response, but this is unneeded and could actually hinder secondary response if it is creating tools which are less effective.