In the study published in Science Immunology, scientists from the Vlaams Instituut voor Biotechnologie (VIB) and Ghent University, working with Danish partners, examined how early viral illness intersects with inherited allergy risks.
Their findings point to a specific window early in life when the immune system is highly sensitive to both infection and family history.
Prof. Bart Lambrecht of VIB-UGent said the research team has been trying to understand why some children with genetic vulnerability go on to develop asthma while others do not.
Insights from Danish population data
To investigate these relationships, the group drew on Denmark’s national health registries, which track birth information, infections, and later diagnoses across the entire population.
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By comparing early RSV cases with long-term outcomes, the researchers identified a pattern: children who had severe RSV early in infancy were more likely to show heightened immune reactions to environmental allergens, particularly in families where asthma or allergies were already present.
The team paired those registry observations with laboratory studies designed to explore how viral exposure may shape immune cells as they develop.
According to the authors, the two approaches converged on the same idea, that RSV can tilt a newborn’s immune system toward stronger-than-usual responses to routine allergens such as house dust mites.
What prevention appears to change
One of the strongest signals came from experimental models in which newborns were shielded from RSV entirely.
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In those cases, the immune changes associated with asthma did not appear.
The researchers say this finding suggests that preventing RSV early in life could have benefits that extend beyond the immediate illness.
Prof. Hamida Hammad, a co-senior author, said the results may help parents and clinicians understand the broader value of RSV prevention tools now being introduced worldwide.
Growing use of new RSV interventions
Several countries are rolling out maternal RSV vaccination during late pregnancy alongside long-acting antibody treatments for infants.
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Health authorities have emphasized the tools’ success at reducing hospitalizations, but uptake has varied.
The new research may influence how pediatricians frame the long-term implications when discussing prevention with families.
Sources: Science Daily, and Science Immunology.
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