The goal of this clinical research is to learn if Imunoglukan P4H® as an add-on therapy to the standard of care treatment according to the EPOS guidelines (intranasal corticosteroids and saline irrigation) can help to prevent CRS exacerbations, respiratory tract infections and reduce the use of antibiotics and intranasal corticosteroids in newly diagnosed children over 12 years of age and adults with CRS without nasal polyps.

The investigational product, Imunoglukan P4H® capsules, will be added to the standard of care treatment according to the EPOS guidelines (intranasal corticosteroids and saline irrigation) as prescribed by their treating physician.

Participants: Newly diagnosed patients over 12 years of age with a diagnosis of chronic rhinosinusitis without nasal polyps meeting the inclusion criteria.

Sites: 5; Czech republic (2) and Slovakia (3) Study duration: 12 moths: 3 months treatment + 3 months follow-up + 3 months treatment + 3 months follow-up

Randomization:

• Control group: Standard of care treatment according to EPOS guidelines (INCS and saline irrigation)
• Active group: Standard of care treatment according to EPOS guidelines (INCS and saline irrigation) + Imunoglukan P4H® capsules (IMG® 100 mg + Vitamin C 100 mg in 1 capsule)

Participants will:

• take standard of care treatment according to EPOS guidelines.
• take Imunoglukan P4H® every day for 3 months then there will be three months follow-up (without Imunoglukan P4H®), this cycle will be repeated twice (only participants in the active group).
• visit the clinic for control visits one month after the study initiation and then every three months during 12 months study period (SNOT-22 questionnaire, VAS scale for evaluation of CRS severity by treating physician, Swab from the upper aerodigestive tract, rhinoendoscopic examination)
• keep a diary of their symptoms (incidence and duration of CRS exacerbations and acute respiratory infections, use of antibiotics, use of intranasal corticosteroids and other symptomatic treatments)
• record number of emergency department visits, hospitalizations, doctor visits and missed work/school days.
• record incidence of potential adverse events

Inclusion Criteria:

• age over 12 years
• signed informed consent
• patients with newly diagnosed CRS without nasal polyps (meeting the criteria for the definition of CRS according to EPOS)
• patients without anatomical abnormalities causing nasal obstruction (nasal septal deformity, nasal turbinate hyperplasia, tumours, craniofacial deformities)
• patients able and willing to complete the questionnaires, undergo rhinoendoscopic examination, upper aerodigestive tract swabs and follow-up outpatient examinations

Exclusion Criteria:

• refused informed consent
• inability/unwillingness to complete the questionnaire, undergo rhinoendoscopic examination, upper aerodigestive tract swabs, follow-up outpatient examinations
• inability/unwillingness to use the product in accordance with the research protocol and compliance < 75%
• patients with protracted rhinosinusitis, exacerbations rhinosinusitis with the presence of an asymptomatic period
• patients with CRS during conservative treatment
• patients with CRS after previous surgical treatment
• patients with grade 3 nasal polyps
• patients with adenoid vegetations/persistent pharyngeal tonsils (especially if children are included in the study)
• patients with CRS with anatomical abnormalities causing nasal obstruction (septal deformity, turbinate hyperplasia, tumors, craniofacial abnormalities)
• patients with significant immunodeficiency
• patients with mucociliary transport disorders (e.g. cystic fibrosis, primary ciliary dyskinesia)
• patients taking other immunomodulating preparations regularly and for a long time (e.g. beta-glucans, Preventan, vitamins C and D, probiotics, Echinacea, bacterial lysates, etc.)
• pregnant and breastfeeding women