mRNA vaccine shows promise for treating food allergies affecting 300,000 Spaniards

A person with a food allergy lives in a state of constant vigilance. Every meal requires inspection. Every ingredient label demands attention. Cross-contamination lurks in shared utensils, in restaurant kitchens, in the invisible residue of someone else's lunch. For those with nsLTP syndrome—a particularly stubborn form of food allergy common around the Mediterranean—the burden multiplies. Their immune systems react not to a single food but to a protein found across dozens of them: peaches and almonds, hazelnuts and tomatoes, celery and pollen. One person can be allergic to forty different things at once, all because their body recognizes the same troublemaking protein in each.

In Spain alone, roughly 300,000 people navigate this reality. Across Europe, the number exceeds seven million. Until now, their options have been grim. Avoid the foods—all of them, if you can identify them. Or undergo a long immunotherapy treatment using peach extract, a process that stretches three to five years and often fails to address the cross-reactive allergies that make the condition so complex. Many patients abandon the treatment midway, frightened by the risk of severe reactions.

A team of researchers led by Esperanza Rivera de Torre at Denmark's Technical University has developed something different: an mRNA vaccine designed to retrain the immune system. The approach uses engineered consensus allergens—synthetic proteins built from the natural ones that trigger multiple allergies—packaged in messenger RNA technology. When injected, the vaccine teaches the body's immune cells to tolerate these proteins rather than attack them. In mice, three doses produced a strong response with minimal side effects. The researchers hope that in humans, two or three injections might suffice.

The work represents a collaboration spanning institutions across Europe: the Technical University of Denmark, Spain's Complutense University in Madrid, the IBIMA research platform in Málaga, and specialists from Barcelona's Vall d'Hebron and Clínic hospitals. Their findings, published in Nature Communications, suggest a path forward not just for nsLTP allergies but potentially for peanut allergies, shellfish allergies, egg allergies, and milk allergies—any condition rooted in protein sensitivity.

Victoria Cardona, head of allergy services at Vall d'Hebron Hospital, explains the clinical reality that makes this work urgent. The peach skin allergy serves as the textbook example: that single protein family has forty distinct variants scattered across fruits, nuts, legumes, and pollens. A patient can develop anaphylactic shock from accidental exposure. Current sublingual immunotherapy, while safe, addresses only food allergies, not environmental ones, and it doesn't guarantee tolerance to cross-reactive allergens. For many patients, it simply doesn't solve the problem completely.

Rivera de Torre emphasizes that the vaccine's advantage lies in its adaptability. A single treatment could theoretically address multiple allergies stemming from the same protein family. The mRNA delivery system allows the allergen to reach immune cells effectively without triggering the adverse reactions that cause patients to lose faith in their treatment. The preclinical data, she notes, point in the right direction, though human efficacy remains to be proven.

One question remains unresolved: could such a vaccine prevent allergies from developing in the first place? Cardona suggests the answer is no, at least not yet. Vaccinating healthy people against dozens of potential allergens would be impractical. But Rivera de Torre proposes an alternative: applying the treatment during the earliest stages of sensitization, before additional allergies emerge, to halt the progression of the disease itself. That possibility—stopping an allergy before it takes root—represents the frontier this research now approaches.