Um, well okay then, want a lollipop?

"Do you know what a vaccine does?" The doctor asked B. "It puts pathogens in your system so that your B cells and T cells can learn how to fight a full infection," B replied, having repeatedly watched a youtube video on the topic. "B and T cells are lymphocytes." The doctor peered over his glasses at B. His puzzled frown and stunned silence showed that his 40 years of medical experience had failed to prepare him for such a response. "Speaking of which, I don't want a needle," B continued obliviously. "Please use a nasal spray."