People have been using small amounts of virus to protect against serious illness for thousands of years. In 1796, an English doctor named Edward Jenner had a breakthrough, using the disease cowpox to inoculate people against the different and far more serious disease smallpox, creating the first vaccination to be referred to with that term. Less than 200 years later, in 1979, smallpox was completely eradicated worldwide.
Vaccination works by priming the immune system to fight a particular kind of infection, so that if that infection comes, the body is ready for it. The immune response creates a new type of defense every time it encounters an infection it hasn’t encountered before; immunization makes it possible for a defense to be prepared in advance by simulating infection without causing illness.
A vaccine can take the form of analogues to infectious agents, synthetic forms of them, or even actual infectious agents that have been killed or rendered harmless. The most common vaccines given routinely include those against mumps, measles, hepatitis B, whooping cough, and HPV, and the flu vaccines made available every year as that virus changes.
Now a new vaccine development technique may be making it possible for doctors top protect against a wider variety of conditions than ever before. While most current vaccines are specific to a particular illness, some are broader in scope, providing immunity against a group of diseases. However, these are often weaker and have a greater risk of side effects. New modular techniques allow the creation of immunizations that function like the narrowly targeted ones, with a similarly low incidence of side effects, but identify themselves to the immune system as a number of different infections, providing the breadth of protection of the more varied vaccines. This provides better protection with fewer shots, giving patients—including young patients—an easier time.