Why do we need multiple doses of a vaccine?

Our immune system normally starts to form a memory of how to fight different diseases after infection or vaccination. It does this by creating memory cells. But why do we need more than one vaccine dose, and why does the gap between doses differ from vaccine to vaccine?

This video was produced by Cloud Chamber Studios for the British Society for Immunology, and is narrated by Professor Donald J. Davidson at the University of Edinburgh. Our 'Immune Memory & the Coronavirus' series explains the detail of how your immune system remembers illnesses it has seen before.

Видео Why do we need multiple doses of a vaccine? канала Cloud Chamber Studios UK Science Animation