The vaccine induces an immune reaction that results in antibodies. A few hundred different types. A real infection results in more than 1000 different antibodies. The developers of the monoclonal antibodies tested these antibodies and found the best ones (most neutralizing and can attack virus variants). The monoclonal antibody "cocktails" contain just two different antibody types.
Edit: The antibodies that are created by the immune system are created by b-cells and some b-cells will stay in the body and wake up when the virus is detected again. The monoclonal antibodies just vanish without a long lasting effect. Because there is no b-cell training, they are just a short-term treatment and not a vaccine.
Regardless of the mechanism of the spike proteins (either direct injection or produced your body), or direct injection anti-bodies, if the pharma companies are being truthful (big "if") then the stats are about the same.
It's about antibodies, not spike proteins. Antibodies is the stuff that binds to spike proteins. That has two effects: Antibodies can block the part of the spike proteins that binds with cells, then they are "neutralizing" antibodies - the best of the best. But even the antibodies that bind elsewhere are valuable: They mark the spike protein so that immune system cells can find and destroy them (they act as target painters). Natural infection creates more neutralizing antibodies than vaccination. Monoclonal antibodies are neutralizing.
(post is archived)