NEW YORK (AP) — A number of scientists have wondered if aluminum, a vaccine additive that has been used for decades, had a role in allergies and asthma in children.

Even if a link were ever found, the life-saving benefits of the vaccines are still likely to outweigh the asthma risk, said Dr.

They also noted the findings include hard-to-explain inconsistencies, like why, in one subset of thousands of fully vaccinated kids, more aluminum exposure didn’t seem to result in a higher asthma risk.

The study, released Tuesday, suggests that young children who were vaccinated with most or all of the recommended aluminum-containing vaccines had at least a 36% higher risk of being diagnosed with persistent asthma than kids who got fewer vaccines.

Several previous studies didn’t find a link between aluminum-containing childhood vaccines and allergies and asthma.

And mice injected with aluminum suffer an immune system reaction that causes the kind of airway inflammation seen in childhood asthma.

“Based on what I consider limited animal data, there is a theoretical risk that the aluminum in vaccines could influence allergy risk,” said Daley, an associate professor of pediatrics at the University of Colorado School of Medicine.

In 2013, the Institute of Medicine — now known as the National Academy of Medicine — called for more federal research into the safety of childhood vaccines, including their use of aluminum.

children born from 2008 to 2014, looking at whether they got vaccines containing aluminum before age 2 and whether they developed persistent asthma between ages 2 and 5.

They wanted to see if kids with eczema were more or less sensitive to aluminum in vaccines, compared with children who did not have early eczema.

The researchers found that for each milligram of aluminum received through vaccines, the risk of persistent asthma rose 26% in the eczema kids and 19% in kids who did not have eczema.

Overall, kids who got 3 milligrams or more of vaccine-related aluminum had at least a 36% higher risk of developing persistent asthma than kids who got less than 3, Daley said.