Early peanut introduction can prevent allergy for infants across risk categories

LOUISVILLE, Ky. — The medical community should ask two questions about preventive peanut allergy interventions among infants, according to a presentation at the American College of Asthma & Immunology Annual Scientific Meeting.

“First, is it worthwhile targeting the whole population of infants if only a fragment of the population is at risk for peanut allergy?” Gideon Lack, MD, professor of pediatric allergy at King’s College London and head of the children’s allergy service at Guys’ and St. Thomas’ NHS Foundation Trust, said in his presentation.

“But if a significant amount of peanut allergy occurs across different groups of the population, then is it worthwhile targeting all these groups?” he continued. “We need the second question to be answered.”

Lack and his colleagues conducted a meta-analysis of two studies — LEAP, or Learning Early About Peanut Allergy, and EAT, or Enquiring About Tolerance — which examined the effects of early introduction of peanut into infants’ diets.

“We put them into an integrated database using skin tests, specific IgE and positive challenge outcomes, and this provides for a more accurate overall effect estimate,” Lack said. “It increases the power because we’ve got a larger sample size. But it allows you to look into covariates and subgroups with more precision and more power as well.”

For example, 33.3% of the infants with severe eczema who avoided peanut introductions developed peanut allergy. But despite this high risk, these infants only comprise 6.64% of the peanut allergy population burden, Lack said. Applying peanut allergy prevention strategies to these patients only reduces the overall burden by 4.55%.

Infants who do not have eczema do not have increased risk for peanut allergy, so why bother subjecting them to allergy prevention interventions, Lack asked hypothetically.

“They actually make up 33% of the peanut allergy burden because although the risk is lower, there are more of these kids around,” Lack explained. “You need to focus on these kids as well.”

Ethnicity is another risk factor, Lack said, noting how the intervention does not seem to work as well among non-white infants in Australia, and particularly does not work well for Asian infants.

“But here across the board, you can see in intention-to-treat and per-protocol populations that there is a big treatment effect whether you’re Asian, Black, Caucasian or mixed ethnicity,” he said.

Skin prick testing also indicated successful treatment when infants in Sweden and Norway, who consumed peanut protein five times a week beginning at age 12 weeks, were compared with those who avoided peanut.

“We showed a very big effect in the intention-to-treat group and an even bigger effect in the per-protocol group, about a 75% reduction,” Lack said. “This would seem to work around the world.”

Although peanut allergy occurs most often in infants with severe eczema or egg allergy, Lack said, most of the population burden is experienced by infants who do not have eczema or who have mild eczema because they make up most of the population.

Although targeting early peanut introductions exclusively to infants with severe eczema would reduce the population burden of peanut allergy by 6%, early introduction across the entire infant population would reduce the burden by 88%, he continued.

The intervention also is highly effective for all infants regardless of their risk category, including eczema severity, ethnicity, egg allergy and sensitization, Lack said, and it is most effective when it is initiated before age 6 months.

“All infants in the general population will be encouraged to consume peanut products once they have reached 4 months of age,” Lack said.