I would like to better understand how each of the vaccines we currently recommend work. So essentially my question is about your favorite source for vaccinology, but I am interested in details that are not so readily available in sources like the CDC website. What type of immunity is necessary for protection for each infectious disease we have a vaccine against? Why do we need multiple doses and boosters for certain vaccines? How did we arrive at the conclusion that we need this many dose administrations and boosters (seminal studies)?