* serious sars-cov-2 infection requiring hospitalization or oxygen supply * chronic diseases under regular medication (eg asthma, allergic rhinitis ...) * congenital or acquired immunodeficiency * body mass index (bmi)\> 30 * coagulation disorders * short bowel syndrome or any surgery on the gastrointestinal tract. * metabolic disorders (diabetes, etc.). * heart failure and cardiac medical history * pregnant women. * hiv positive. * immunocompromised * history of significant gastrointestinal diseases * use of other probiotics during the last month. * uncertainty about the willingness or ability of the participant to comply with the requirements of the protocol.

* serious sars-cov-2 infection requiring hospitalization or oxygen supply * chronic diseases under regular medication (eg asthma, allergic rhinitis ...) * congenital or acquired immunodeficiency * body mass index (bmi)\> 30 * coagulation disorders * short bowel syndrome or any surgery on the gastrointestinal tract. * metabolic disorders (diabetes, etc.). * heart failure and cardiac medical history * pregnant women. * hiv positive. * immunocompromised * history of significant gastrointestinal diseases * use of other probiotics during the last month. * uncertainty about the willingness or ability of the participant to comply with the requirements of the protocol.

- serious sars-cov-2 infection requiring hospitalization or oxygen supply - chronic diseases under regular medication (eg asthma, allergic rhinitis ...) - congenital or acquired immunodeficiency - body mass index (bmi)> 30 - coagulation disorders - short bowel syndrome or any surgery on the gastrointestinal tract. - metabolic disorders (diabetes, etc.). - heart failure and cardiac medical history - pregnant women. - hiv positive. - immunocompromised - history of significant gastrointestinal diseases - use of other probiotics during the last month. - uncertainty about the willingness or ability of the participant to comply with the requirements of the protocol.

- serious sars-cov-2 infection requiring hospitalization or oxygen supply - chronic diseases under regular medication (eg asthma, allergic rhinitis ...) - congenital or acquired immunodeficiency - body mass index (bmi)> 30 - coagulation disorders - short bowel syndrome or any surgery on the gastrointestinal tract. - metabolic disorders (diabetes, etc.). - heart failure and cardiac medical history - pregnant women. - hiv positive. - immunocompromised - history of significant gastrointestinal diseases - use of other probiotics during the last month. - uncertainty about the willingness or ability of the participant to comply with the requirements of the protocol.