inclusion criteria: - healthy - age over 25 years - the outcome of the following examinations should be clinically insignificant: medical and surgical history (hypo-, hypertension, allergy, other diseases, major surgery, micturition, defecation, sleep, illness within the last 4 weeks prior to the start of the trial); - participant vaccinated with sinovac over 4 months - anti-sars cov 2 neutralizing antibody is negative in serum.

inclusion criteria: - healthy - age over 25 years - the outcome of the following examinations should be clinically insignificant: medical and surgical history (hypo-, hypertension, allergy, other diseases, major surgery, micturition, defecation, sleep, illness within the last 4 weeks prior to the start of the trial); - participant vaccinated with sinovac over 4 months - anti-sars cov 2 neutralizing antibody is negative in serum.