Post Authorization Efficacy and Safety Study (PAES) to Confirm and Collect More Clinical Data of Buccalin® Tablets in the Prophylaxis of Recurrent Lower Respiratory Tract Infections (RLRTIs).

The goal of this clinical trial is to assess if BUCCALIN® works In the Prophylaxis of Recurrent Lower Respiratory Tract Infections (RLRTIS). It will also evaluate the safety of BUCCALIN®.

The primary aim is to reduce the number of infection episodes in the treatment period (12 months) in the BUCCALIN® group versus the Placebo group.

Patients diagnosed with RLRTIS will be screened for enrolment. Patients will be requested to provide informed consent before the start of the study related assessments.

Eligible patients who meet the study inclusion and exclusion criteria will be randomized with a 1:1 ratio allocation to the 2 treatment groups.

Researchers will compare BUCCALIN® (gastro-resistant tablets) to a placebo (gastro-resistant tablets containing only excipients) to treat RLRTIS.

Patients who participate in the study will perform several study visits divided as reported below:

* Run-in phase (12 months): patients will not receive any treatment. This phase is designed to increase adherence to the study and reduce loss to follow-up in the clinical trial. During this phase, patients should experience ≥ 2 episodes of RTIs to be eligible for the Treatment period.
* Treatment period (12 months): patients will receive BUCCALIN® or Placebo treatment for 12 consecutive months (3 days per month, posology as per authorized SmPC).
* Follow-up period (12 months): patients will not receive any treatment. This phase is designed to observe how patients respond to treatments.


Eligibility Criteria:
Inclusion Criteria:

1. Patients willing and able to provide voluntary informed consent and to follow protocol requirements.
2. Male or females from 18 to 99 years old, (Adult, Older Adult).
3. Patients with Recurrent LRTIs (≥2 episodes of RTIs within 12 months prior the run-in phase and during the run-in phase), based on medical recording or reported history. RLRTIs will include acute bronchitis, and exacerbations of chronic lung disease (asthma and/or COPD and/or bronchiectasis).
4. Patients not vaccinated and/or vaccinated with specific vaccination against the most common pathogens for respiratory infection\*:

   * Anti-pertussis vaccination
   * Covid-19 vaccination
   * Respiratory Syncytial Virus vaccination
   * Influenza vaccination
   * Pneumococcal vaccination
5. Patients vaccinated with other types of vaccine, e.g. hepatitis b vaccination, shingles/herpes zoster vaccination, papilloma virus vaccine.
6. RLRTIs documented by appropriate microbiological diagnostic test.

   * Any all the above vaccination are accepted within 12 months prior to the run-in phase and during the run-in phase.

Exclusion Criteria:

1. Female patient: pregnant, lactating or planning pregnancy (Female of child-bearing potential will undergo urine pregnancy test).
2. Female of potential child-bearing that does not use at least one effective contraceptive method for the entire study.
3. Contraindication or known hypersensitivity to the active ingredients of bacterial lysates or any excipients listed in the ingredients.
4. Pneumonia (based on the EMA Referral Procedure EMEA/H/A-31/1465).
5. Respiratory diseases of infectious of any other origin (tuberculosis, cystic fibrosis).
6. HIV infection or any type of congenital or iatrogenic immune deficiency (including IgA deficiency).
7. Severe heart failure (NYHA class III and IV).
8. Haematologic diseases excluding mild to moderate anaemia (defined according to the National Cancer Institute as follows: Mild: Hemoglobin 10.0 g/dL to lower limit of normal. Moderate: Hemoglobin 8.0 to 10.0 g/dL).
9. Renal failure (eGFR \< 30 mL/min).
10. Liver damages defined by the METAVIR classification (F0-F2).
11. Malignancies with a remission period of \< 5 years.
12. Injection or oral administration of steroids within 4 weeks prior to study enrolment.
13. Previous and/or concomitant immunosuppressants, immunostimulants, or gamma globulins within 6 months prior to study enrolment.
14. Previous use within last 6 months of enrolment or ongoing use of bacterial lysates.
15. Any major surgery within the last 3 months prior to study enrolment.
16. Wheezing documented to be caused by gastroesophageal reflux.
17. Patient legally or mentally incapacitated unable to give informed consent for the participation in this study.
18. Patient who is unable or unwilling to comply with the appointments or with all the requirements of the Protocol.
19. Autoimmune diseases and acute intestinal infections, as reported in Buccalin® SmPC.