Given the value of the vaccine, it’s mindboggling that some in the US would choose not to protect their children. And yet, vaccine rates among US kindergartners fell for the second consecutive year in 2022, a situation the Centers for Disease Control and Prevention said left some 250,000 kids vulnerable to measles. While some of those missed shots were potentially due to challenges accessing timely health care during the pandemic, there’s reason to worry that growing hesitancy about vaccination is also at play.

It does not help that some states are making it easier to forgo routine childhood vaccines. Mississippi, for example, previously led the nation in vaccination coverage for kindergarteners, with more than 98.6% of kids receiving both doses of their MMR shots in the 2021–2022 school year. But anti-vaccine activists succeeded in loosening the state’s childhood vaccination policy, and last year families could for the first time seek religious exemptions for basic shots like MMR, tetanus, polio and others. According to a report from NBC, the state granted more than 2,200 exemptions in the first five months they were allowed.

The shift seemingly reflects a new partisan divide. A recent Pew Research Center poll found a steep drop in the number of Republicans and people who lean Republican who don’t believe vaccines should be required for attending public school.