Does breastfeeding vs not affect when the vaccine will stick? I vaguely recall kids can continue getting maternal antibodies that way.
This is a slight nitpick, but it might be important too. Our bodies don’t “store antibodies”. There isn’t a warehouse full of spare antibodies lying around that we can use up. What we actually have is a population of memory B cells (and T cells, but let’s focus on antibodies). Each cell has rearranged its DNA to make one particular antibody. When a new antigen invades the body, cells that make an antibody that can respond to it start dividing like crazy to fight the infection. As they divide, they do some interesting molecular tricks to tweak the antibodies they make to make them more effective. Some of these cells become long-lived memory B cells and go hang out in the lymph nodes forever. If and when the antigen reinvades the body, the relevant cell(s) can immediately start growing and making antibodies to fight the new infection without having to go through all that tweaking all over again.
Antibodies are protein molecules. B cells are the factories that make the antibodies. In essence, one memory B cell can divide into enough new B cells to make enough antibodies to fight any new infection. We don’t store the antibodies themselves; we store the information on how to make them.