Before the vaccine, the United States saw approximately 4 million cases of measles each year and 400 to 500 deaths. These are the stats that vaccine-deniers tend to emphasize—a relatively low number of deaths compared with the number of infections. However, those statistics alone leave out a big part of measles infections. Prevaccine, almost 48,000 people were also hospitalized each year because of measles and measles complications. One in 20 of those infected developed pneumonia. More rarely but more seriously, each year 1,000 became chronically disabled due to measles encephalitis.
Excerted from: