A new year brings a flurry of legislative activity. Many states will be considering bills that limit vaccine choice, whether by eliminating or restricting exemptions or mandating vaccines for children or certain workers.

Patients deserve a right to decide which medical treatments to receive, especially when there are safety concerns. There is plenty of scientific data that throws the safety of vaccine ingredients into serious question. Take aluminum, for example—a common vaccine ingredient:

• Aluminum is a well-documented neurotoxin that has been linked to Alzheimer’s disease, epilepsy, asthma, hyperactivity, and Down’s Syndrome.

• The FDA has set a limit on the amount of aluminum that can be in vaccines, but this number was based on the amount of aluminum required to enhance the effectiveness of the vaccine. The agency has not empirically determined the safest amount of intramuscularly injected aluminum, relying instead on the hope that current levels are safe. Note the word “injected.” It is one thing for the body to handle aluminum in our food, because our liver protects us. But it can’t protect us when we are injected with poison.

• New studies provide stunning information about what happens to aluminum after it’s injected into muscle. In some mice, it travels to the brain, where it can still be detected a year later. It also travels to the spleen and lymph nodes, where it can still be detected 270 days after vaccination.

In addition to concerns about ingredients—including the mercury that is used as a preservative in flu shots, even for children—the national vaccine schedule has never been rigorously evaluated for safety. This was the determination not of some “anti-vaxxer” group, but of the National Academy of Medicine (formerly the Institute of Medicine), which advises the government on issues relating to medicine and health. In a 2013 report, the Academy concluded, “Key elements of the schedule—the number, frequency, timing, order, and age at administration of vaccines—have not been systematically examined in research studies.”