Vaccines are among the greatest achievements in medical science, saving millions of lives every year. They protect individuals and entire communities from infectious diseases such as measles, polio, influenza, and COVID-19. Understanding how vaccines work begins with knowing how the body's immune system defends itself from harmful invaders. Through decades of research, vaccine science has developed safe and effective ways to train the immune system to recognize and combat pathogens—without causing illness.
This article provides a detailed look at how the immune system works, how vaccines mimic natural infections to build immunity, and the modern innovations shaping the future of vaccination.
