Can someone explain the discrepancy here? I don't get it: > Before 1963, when the vaccine was introduced to the United States, 3 million to 4 million Americans

Can someone explain the discrepancy here? I don't get it: > Before 1963, when the vaccine was introduced to the United States, 3 million to 4 million Americans were infected each year, with thousands developing complications that led to hospitalization or lifelong disability. Approximately 400 to 500 people died every year. > Today, the Centers for Disease Control and Prevention estimates that one to three children out of 1,000 infected with measles will die from complications. Even after taking age distribution into account, this would mean that measles is at least 10 times more deadly today than it was before 1963. Is this actually a typo?