The BBC drama Call the Midwife follows a group of progressive nuns and nurses in 1957 London who cycle from house to house delivering babies and dispensing free medical care. If you’ve ever watched it, you already know how deadly diseases such as measles, polio, and whooping cough (pertussis) can be. Today, in 2017, we have vaccines against all three of these diseases—and more. So our children should be protected, these preventable illnesses confined to the past and to binge-watchable historical dramas. Right?