Existing mRNA vaccines theoretically provide antibodies to about 42 epitopes of the original spike protein. So, they are very effective against the original strain as any one of these antibodies would be neutralizing.
Let’s say for example that only 10 out of 42 are neutralizing for omicron. That means that many people will be unlucky and not produce enough of the right antibodies to stop the omicron at first, thus their protection has eroded. But some will be lucky enough to produce the necessary amount of the right antibodies. So the protection was not completely bypassed.
Existing mRNA vaccines theoretically provide antibodies to about 42 epitopes of the original spike protein. So, they are very effective against the original strain as any one of these antibodies would be neutralizing.
Let’s say for example that only 10 out of 42 are neutralizing for omicron. That means that many people will be unlucky and not produce enough of the right antibodies to stop the omicron at first, thus their protection has eroded. But some will be lucky enough to produce the necessary amount of the right antibodies. So the protection was not completely bypassed.