Kindergarten vaccine exemptions hit record high nationwide, CDC data shows

U.S. kindergarten vaccine exemptions reached a record 4.2% last school year, driven largely by non-medical opt-outs, according to new CDC data. While states like Idaho saw rates skyrocket past 17%, California maintained one of the lowest exemption rates in the country at just 0.1%. UCSF infectious disease expert Dr. Peter Chin-Hong broke down what the dropping national MMR coverage means for herd immunity.