Study to see if childhood vaccines and asthma are linked

New York – Many scientists have wondered whether aluminum, a vaccine additive that has been used for decades, has a role in allergies and asthma in children.

A new federally-funded study has found a possible link, but experts say the study has serious shortcomings and is no reason to change current vaccine recommendations. The study does not claim that aluminum causes respiratory conditions, and officials said more research is needed to confirm any associations that were not seen in previous studies. says.

Even if the link is found vaccination The study’s first author, Matthew Daley, PhD, said the risk of asthma is still likely to be outweighed. But he added that if the results are confirmed, it could prompt new work to redesign the vaccine.

Dr. Paul Offitt of the Children’s Hospital of Philadelphia worries that this flawed study will unnecessarily scare some families away from proven vaccines.

“You need extraordinary evidence to make extraordinary claims,” said Offitt. The study provides no such evidence, he said.

He and other outside experts said that Daly and his colleagues were unable to explain the effects of several potentially important ways in which children are exposed to aluminum, such as in the air and in their diet.

They also noted that the findings contain inconsistencies that are difficult to explain. For example, in some of the thousands of fully vaccinated children, increased aluminum exposure did not appear to increase the risk of asthma.

A CDC official said in a statement that aluminum-containing vaccines “do not appear to account for the overall trend we are seeing.”

The study, released Tuesday, suggests that infants who received most or all of the recommended aluminum-containing vaccines had at least a 36% higher risk of being diagnosed with persistent asthma than children who were not vaccinated. doing.

Aluminum has been used in some vaccines since the 1930s as a component called an adjuvant that induces stronger immune defenses.

According to US recommendations, children should be vaccinated against 15 diseases by the age of two. Aluminum adjuvants are included in seven of her vaccines.

Aluminum adjuvants have long been considered safe and effective. Still, scientists have noted rising rates of allergies and asthma among U.S. children for three decades, beginning around 1980, and some still wonder if there’s a relationship. (These rates have been flat for about a decade and have declined somewhat in recent years, but the reasons for this are not fully understood.)

Several previous studies have found no association between pediatric vaccines containing aluminum and allergies and asthma. However, other studies have linked aluminum in industrial workplaces to asthma.Also, mice injected with aluminum suffer from an immune system response that causes airway inflammation, similar to that seen in childhood asthma. .

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

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

The new research is part of the government’s response to that call, Daley said. It was funded by the CDC and its authors included current and former CDC staff.It was published in the medical journal Academic Pediatrics.

Researchers looked at about 327,000 U.S. children born between 2008 and 2014 to see if they received vaccines containing aluminum before they were two years old, and between the ages of two and five. We investigated whether they had developed persistent asthma.

Asthma is a condition that causes spasms in the lungs, usually due to an allergic reaction. About 4% of her children in the United States under the age of 5 have persistent asthma.

The researchers looked at a variety of factors that could influence the results, including race and ethnicity, whether the child was born prematurely, and whether the child had food allergies or certain other conditions. We have taken steps to explain.

But there were many other factors they couldn’t address. For example, aluminum is routinely found in breast milk, infant formula, and food, but the researchers were unable to obtain data on how much aluminum the children received from their diets. They also had no information on aluminum exposure from the air or environment in which they lived.

The researchers split the study group into two. One of them was about 14,000 children who developed eczema, a skin condition seen as an early indicator of the development of asthma and other allergic conditions. They wanted to see if children with eczema were more or less sensitive to aluminum in vaccines compared to children who did not have early eczema. The remaining 312,000 children did not have early eczema.

Both groups received approximately the same amount of vaccine-related aluminum. The researchers found that the risk of persistent asthma increased by 26% in children with eczema and 19% in children without eczema for each milligram of aluminum ingested by the vaccine.

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

Offitt said the study’s limitations meant it “doesn’t add anything to our understanding of vaccines and asthma.”

But other experts said the researchers drew from a well-respected body of patient data and were careful with the best information available.

“This is public health at its best,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. Our job is to find out what is going on.”

He acknowledged that anti-vaccine activists are likely to jump to conclusions that the evidence does not support. be perceived as untrustworthy, which can further erode trust.

Dr. Sarah Long, professor of pediatrics at Drexel University School of Medicine, agrees.

“I believe in total transparency,” she said. “If you asked a question and spent our (taxpayer’s) money on that question (investigated), I think the results should be televised in all its warts and glory.”

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Associated Health & Science Department is supported by Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.