Vaccines for infectious diseases have changed the trajectory of humankind. In the 20th century alone, smallpox killed more than 300 million people worldwide, and polio killed or paralyzed half a million people each year. Today, thanks to vaccines, smallpox has been eradicated worldwide, meaning it's essentially extinct; and polio has been eliminated in many countries, so the disease is no longer endemic to those places.
With the success of vaccines for infectious diseases in mind, scientists have wondered if it might be possible to similarly harness the power of the immune system against other conditions. Now, researchers are working to develop vaccines for cancer.
