See the Dramatic Consequences of Vaccination Rates Teetering on a ‘Knife’s Edge’ As U.S. childhood vaccination rates sway on a “knife’s edge,” new 25-year projections reveal how slight changes in national immunization could improve—or drastically reverse—the prevalence of measles, polio, rubella and diphtheria By Lauren J. Young edited by Dean Visser Measles, rubella, polio and…