A new study by the University of Pittsburgh, published in the New England Journal of Medicine, looked at reports of polio, measles, rubella, mumps, hepatitis A, diphtheria and pertussis (whooping cough) since 1924.
The researchers looked at disease reports before and after the availability of vaccines and estimated the number of cases that would have occurred without immunisation programmes.
This involved a huge effort to mine millions of case reports. Read more about the project or watch the video below.
Dr Donald S. Burke, the dean of Pittsburgh’s graduate school of public health and an author of the article, said that around three million to four million deaths were also prevented.
Pointing to the research results, Dr. Burke said, “If you’re anti-vaccine, that’s the price you pay.”