Alarmed at this growing resistance to prevention of deadly infectious disease, public health officials in California sought a change to the exemption. The California Assembly passed a bill requiring parents opting out of vaccinations to obtain a healthcare professional’s signature confirming that the parents had first received information about the risks and benefits of vaccines. A legislator-pediatrician authored the bill, which received broad support from medical entities in California, according to Bruce Pomer, executive director of the Health Officers Association of California, writing in an op-ed at Capitol Weekly.

But, there was a hitch, and now some public health experts are deeply concerned that a loophole in the new exemption language could actually end up boosting opt-outs.

The loophole, included at the direction of California Governor Jerry Brown, is a religious exemption that would allow parents to evade seeing a medical professional. The evasion is as easy as checking a box [PDF] declaring that one’s religion precludes one from seeing said medical professionals. Which religions that might be is unclear; those that appear to be most common in, say, Marin County, don’t tend to prohibit adherents from turning to licensed healthcare practitioners.