A RANDOMISED, double-blind, placebo-controlled trial has found that codfish oral immunotherapy (OIT) can significantly increase desensitisation rates in young children with fish allergy, although sustained unresponsiveness after treatment cessation remains limited.
In the study, 70 children aged 2–10 years with confirmed codfish allergy were enrolled in Hong Kong. All participants had reacted to codfish protein during double-blind, placebo-controlled food challenges (DBPCFC). Children were randomised 1:1 to receive either codfish OIT or placebo for 52 weeks, followed by an 8-week avoidance period. The daily maintenance dose in the active arm was 1000 mg of codfish protein.
Desensitisation Rates Significantly Higher with Codfish Oral Immunotherapy
The primary endpoint was desensitisation at week 52. At the end-of-treatment food challenge, 43% (15/35) of children receiving OIT achieved desensitisation, compared with 11% (4/35) in the placebo group (risk difference 32%, 95% CI 9–51%; p=0.003). Median cumulative tolerated protein was significantly higher in the OIT arm (4330 mg versus 0 mg; p<0.001).
Sustained unresponsiveness (SU), assessed at week 60 after 8 weeks of avoidance, was achieved in 23% of children in the OIT group and 9% in the placebo group. However, this difference was not statistically significant (risk difference 14%, 95% CI −5% to 33%; p=0.332), highlighting ongoing challenges in achieving durable remission.
Cross-Reactivity to Salmon and Catfish Allergens Reduced
Immunologically, codfish OIT was associated with significant reductions in codfish-specific IgE and rGad c 1-specific IgE, alongside increased codfish-specific IgG4 and reduced skin prick test reactivity. The investigators also reported reduced IgE cross-reactivity to salmon and catfish allergens, suggesting potential broader immunomodulatory effects.
In terms of safety, the regimen was generally well tolerated. Most adverse events were mild, and moderate-to-severe reactions were infrequent. Epinephrine use was low and comparable between groups (3% in each arm).
The trial provides evidence that codfish OIT can meaningfully increase desensitisation in children as young as two years. However, the relatively low rates of sustained unresponsiveness indicate that longer treatment duration or alternative strategies may be needed to achieve lasting tolerance in paediatric fish allergy.
Reference
Leung ASY et al. Codfish oral immunotherapy in children aged 2–10: randomized placebo-controlled study. Allergy. 2026;doi: 10.1111/all.70268.
Featured image: karepa on Adobe Stock
