This natural experiment confirmed the science: diseases we had eliminated returned. If you’d nostalgically pined for a return to old-time America, you got your way. U.S. cases of whooping cough had bottomed out at around 8,000 through the early 2000s; by 2012, we were up to 48,000—the 1955 level. The outbreak in California (as in Washington State) was the worst since the 1940s—hundreds were hospitalized and ten were dead in one year. Twenty of the Americans who got whooping cough in 2012 died, most of them newborns. Measles cases increased tenfold within a few years.
