In the recent TED-Ed animation “How Do Vaccines Work?” educator Kelwalin Dhanasarnsombut explains the history of vaccines, the science behind them, and how vaccines help the body to stave off infections, illness, and disease.
To understand how vaccines function, we need to know how the immune system defends us against contagious diseases in the first place. When foreign microbes invade us,the immune system triggers a series of responses in an attempt to identify and remove them from our bodies. …These innate immune responses also trigger our second line of defense, called adaptive immunity. …Despite this smart response, there’s still a risk involved. The body takes time to learn how to respond to pathogens and to build up these defenses. …But what if we could prepare the body’s immune response, readying it before someone even got ill? This is where vaccines come in. Using the same principles that the body uses to defend itself, scientists use vaccines to trigger the body’s adaptive immune system, without exposing humans to the full strength disease.