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Thursday, June 28, 2018

Nonmedical Vaccine Exemptions

 In The Politics of Autism, I look at the discredited notion that vaccines cause autism.

At PLoS Medicine, Jacqueline K. Olive, Peter J. Hotez , Ashish Damania, and Melissa S. Nolan have an article titled "The State of the Antivaccine Movement in the United States: A Focused Examination of Nonmedical Exemptions in States and Counties."  Summary points:

  • 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, AZ, Salt Lake City, UT, Provo, UT, Houston, TX, Fort Worth, TX, Plano, TX, and Austin, TX in the Southwest; Troy, MI, Warren, MI, Detroit, MI, and Kansas City, MO in the Midwest; and Pittsburgh, PA in the Northeast. Additional smaller counties—especially in ID, WI, and UT—also stand out for their high exemption rates.
  • We analyzed the relationship between NME rates and actual vaccine coverage, and found an inverse association between NME rate and measles, mumps, and rubella (MMR) vaccine coverage of kindergarteners in these states (P = 0.03 by Spearman correlation), indicating that states with higher overall NME rates do in fact have lower MMR vaccine coverage (P = 0.007 by beta regression).
  • Our findings indicate that new foci of antivaccine activities are being established in major metropolitan areas, rendering select cities vulnerable for vaccination-preventable diseases. As noted by the recent experience in Anaheim, California, low vaccination rates resulted in a measles outbreak. In contrast, state closure of NMEs has resulted in an increase of MMR coverage.