Researchers have identified a list of metropolitan areas in the US where low vaccination rates could lead to outbreaks of preventable diseases like mumps, whooping cough, measles, and more.

In the study, published in the journal PLOS Medicine, researchers looked at the rates of nonmedical exemptions (NMEs) for vaccines among kindergarten-aged children in the 18 states that allow NMEs. That means states where parents can decline vaccines for their children based on philosophical or religious beliefs, even though there's no medical reason not to vaccinate.



The data show that the NME rates have been on the rise in 12 of those 18 states since 2009, and in those areas, fewer children received vaccines such as MMR, which protects against measles, mumps, and rubella.

Looking at that data county by county, the researchers identified several hot spots where high prevalence of NMEs were clustered, including Seattle and Spokane in Washington; Phoenix; Salt Lake City and Provo in Utah; Houston, Austin, Fort Worth, and Plano in Texas; and Troy, Warren, and Detroit in Michigan. There were also rural areas of concern, such as in Idaho, and other areas like Portland, Oregon; Kansas City, Missouri; and Pittsburgh. The researchers are now looking into why these areas have high NME rates.