A social movement of public health vaccine opposition has been growing in the United States in recent years; subsequently, measles outbreaks have also increased. Since 2009, the number of “philosophical-belief” vaccine nonmedical exemptions (NMEs) has risen in 12 of the 18 states that currently allow this policy: Arkansas (AR), Arizona (AZ), Idaho (ID), Maine (ME), Minnesota (MN), North Dakota (ND), Ohio (OH), Oklahoma (OK), Oregon (OR), Pennsylvania (PA), Texas (TX), and Utah (UT). Several US “hotspot” metropolitan areas stand out for their very large numbers of NMEs. They include Seattle, WA, Spokane, WA, and Portland, OR in the Northwest; Phoenix,...
