Immunomodulatory Effect of Pleuran in Children With Recurrent Respiratory Tract Infections

International, multicentre, prospective, randomized, double-blind, placebo-controlled study with a food supplement Imunoglukan P4H® chewable tablets to evaluate preventive effect on reduction of respiratory tract infections (RTIs) in children with a history of recurrent respiratory tract infections (RRTIs) in the previous infectious season prior enrolment. Participants or their guardians will record the incidence and duration of RTIs in the Patient diary for 3 months.

Study population: Children aged 3-18 years with a history of RRTIs: * Age 3 to 5 years (\< 6 years): 6 or more upper or lower respiratory tract infections from October 2022 until the end of March 2023 * Age 6 to 18 years (≥ 6 years): 3 or more upper or lower respiratory tract infections from October 2022 until the end of March 2023 Study design: International (Slovak republic, Czech republic, Serbia), multicentre (36), prospective, randomized, double-blind, placebo-controlled study Primary endpoint: To evaluate the effect of Imunoglukan P4H® chewable tablets (IMG®+ zinc+ vitamin D3) compared to the placebo group (zinc + vitamin D3) on: • reduction in the number of RTIs episodes (total number) Secondary endpoints: To evaluate the effect of Imunoglukan P4H® chewable tablets (IMG®+ zinc+ vitamin D3) compared to the placebo group (zinc + vitamin D3) on: * reduction in the number of episodes of RTI subtypes * reduction in the duration of RTI episodes (total duration, RTI subtypes) * reduction of the need for antibiotic (ATB) therapy * reduction of the number of missed days at school/nursery due to RTI * reduction of the number of missed working days due to RTIs * reduction of the number of emergency department visits due to RTI * reduction of the number of physician visits due to RTI * tolerability and safety Randomization: * Active group: Imunoglukan P4H® chewable tablets (IMG® 50 mg + Zinc 5 mg + Vitamin D3 10 μg in 1 tablet): * Placebo group: Placebo chewable tablets (Zinc 5 mg + Vitamin D 10 μg in 1 tablet) Dosage: * up to 25 kg of body weight 1 tablet once a day for 3 months * over 25 kg 2 tablets once a day for 3 months Diagnostic procedures: • Patient diary (Incidence and duration of RTIs)