The company’s probiotic blend, AB21, was found to shorten the duration of fever by 40% (1.1 days) and pain/discomfort by 19% (0.7 days), compared to placebo, according to findings published in the European Journal of Pediatrics.
AB21 is formulated with Lactiplantibacillus plantarum KABP-033, L. plantarum KABP-022, L. plantarum KABP-023 and Pediococcus acidilactici KABP-021.
“URIs [upper respiratory tract infections] in children are a significant global health concern,” said Jordi Espadaler, director of innovation at AB-Biotics and co-author on the new paper. “Due to their developing immune systems, children under five years old are a high-risk group, with more cases and serious or fatal outcomes reported yearly than for any other age group.
“This study expands the evidence that AB21 can positively impact viral respiratory infections through its unique mechanism of action, activating the immune system via its effect on immunity cells as well as enhancing the gut barrier function, and reducing local inflammation. Together, the local and systemic effects of AB21 help to accelerate viral clearance, speeding recovery and promoting protection from future infections.”
Study details
The new study is reportedly one of the few pediatric probiotic studies that verified which viruses caused the symptoms, and used both clinical and molecular confirmation.
Seventy-five children aged six months to 5 years were recruited to participate in the randomized, double-blind, placebo-controlled trial. URIs were diagnosed by pediatricians using clear clinical criteria (pharyngitis accompanied by fever) and causative agents were determined by PCR analysis of nasopharyngeal swabs.
The children were then randomly assigned to the AB21 group (4 billion CFUs per day) or placebo for 15 days.
The study allowed use of common over-the-counter medications such as ibuprofen to relieve symptoms, but the use of these treatments was similar between the two groups.
Results showed that children in the probiotic group displayed significantly reduced symptom duration and pain/discomfort.
Additional analysis revealed that body temperature and FLACC (Face, Legs, Activity, Cry and Consolability) scores were significantly lower in the probiotic group, compared to placebo.
Fifteen days after completing the intervention, the data revealed that the probiotic group had significantly lower incidence of nasal congestion and total number of symptoms, suggesting that immune-stimulating effects were seemingly maintained for some time following supplementation.
“Our study suggests the specific probiotic formula containing strains P. acidilactici KABP021 and L. plantarum KABP022, KABP023, and KABP033 helps shorten the duration of fever and pain/discomfort in children with URI with pharyngitis of diverse viral origin,” wrote the researchers. “This formula may also reduce the severity of relapses or new infections for a limited time after completing the intervention.”
Source: European Journal of Pediatrics, 2025, 184, 795. doi: 10.1007/s00431-025-06587-7. ”A probiotic containing L. plantarum and P. acidilactici strains for treating upper respiratory infection in children aged 6 months to 5 years: a randomized, double-blind trial”. Authors: D. Andrade-Platas, et al.
