Modulation of Gut Microbiota by Probiotic in Children With Respiratory Symptoms

Inclusion Criteria: * Preschool children (\>12 months old, \<7 years old). * Having respiratory symptoms (having at least two of the following signs and symptoms: fever (even if only reported not measured), nasal obstruction, chills, sore throat, headache, cough, runny nose, olfactory disturbances, or taste disturbances; Pucarelli-Lebreiro et al., 2022). * Healthy with current weight of P20-P80 percentile chart of children * Infant formula powder does not contain probiotics; prebiotics FOS is not allowed, GOS \<2g/ 100g is allowed * Willing to commit throughout the experiment Exclusion Criteria: * Long term medication \>6 months for any diseases * Deformity * Mothers with metabolic and/or chronic diseases * Current or previous diseases, conditions or interventions that may interfere with the study (such as tolerance and/or growth and development), such as gastrointestinal malformations, chronic diarrhea, malabsorption syndromes, malnutrition, congenital immunodeficiency or surgery * Oral antibiotics within 2 weeks before the intervention * Nutritional supplements containing probiotics and prebiotics (except infant formula) within 2 weeks before the intervention * Foods for special medical purposes or non-standard formula powders for lactose intolerance and galactosemia * Probiotic allergies or possible food allergies (milk, etc.) * Participated in other clinical studies 4 weeks before the intervention * Unwilling to participate for any particular reason