What did Jonas salk invent that is still in use today?

Dr. Jonas Salk created a vaccine for poliomytis or Polio. In 1954, Salk had done the biggest field trial ever recored in history. He did this experiment on over 1.8 million people. There was 2 vaccines. One was the vaccine that he has created and then the Placebo. Then he had a control group. He died on June 23, 1995. He was 80 years old when he died