In the time before widespread vaccination, devastating infectious diseases ran rampant in America, killing millions of children and leaving others with lifelong health problems.
Over the next century, vaccines virtually wiped out long-feared scourges like polio and measles and drastically reduced the toll of many others. Today, however, some preventable, contagious diseases are making a comeback as vaccine hesitancy pushes immunization rates down. And well-established vaccines are facing suspicion even from public officials, with Robert F. Kennedy Jr., a longtime anti-vaccine activist, running the federal health department.
