Most of us know the MMR vaccine protects against measles, mumps, and rubella. Yet most people don't know Maurice Hilleman.

Some say he saved more lives than any other scientist in the twentieth century, by either creating or working on more than twenty five vaccines, including nine of the fourteen that are recommended for children today.

Not bad for a man whose original career goal was to manage a J.C. Penney store. Instead, he earned a Ph.D. in microbiology before spending his career at the drug giant, Merck. His combination of scientific talent and "get it done" attitude made him ideal for vaccine development.

You could see that in his work on the MMR vaccine. At the time, the measles vaccine carried significant side effects which discouraged some from getting it. So, Hilleman, along with a pediatrician, minimized the effects by giving the vaccine along with a shot that temporarily boosted the immune system.

Over the next several years, he developed a safer strain of measles virus still used in today's vaccine. Around the same time, he also began working on the mumps and rubella vaccines.

A strain of the rubella virus had spread around the world, killing eleven thousand newborns in the U.S. and causing birth defects in twenty thousand infants. Soon after refining a safe rubella vaccine, he combined it with the measles and mumps vaccines to create the MMR vaccine.

Today, it's given with the varicella vaccine to protect against chickenpox which Dr. Hilleman also helped developed along with vaccines for hepatitis A and B, meningitis and pneumonia.

By now you can appreciate the world-wide impact of this one scientist, whose legacy is for us to keep getting vaccinated.