Efficacy and Safety of Oral Lactobacillus Plantarum GUANKE (CGMCC NO.21720) in Enhancement of Antibody Level After SARS-CoV-2 Vaccination (Trial 1)

Inclusion Criteria:

1. 18 ≤age ≤59 years;
2. Vaccinated with two doses of SARS-CoV-2 vaccine (manufactured by Sino Biopharmaceutical Limited or SINOVAC BIOTECH CO., LTD.) (≥6 months from the time of vaccination).
3. Not vaccinated third dose vaccination;
4. Voluntarily participate in the study with signed informed consent form.

Exclusion criteria:

1. Pregnancy or lactation period;
2. Infected with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV);
3. Plan to vaccinate third dose of SARS-CoV-2 vaccine within 2 months;
4. History of autoimmune diseases (e.g. rheumatoid arthritis, systemic lupus erythematosus, dry syndrome, etc.);
5. Previously infected with SARS-CoV-2 or close contact of SARS-CoV-2 infected individual;
6. Other SARS-CoV-2 vaccination history (not manufactured by Sino Biopharmaceutical Limited or SINOVAC BIOTECH CO., LTD.);
7. End-stage cancer or other terminal diseases with life expectancy <6 month;
8. History of severe cardiovascular and cerebrovascular diseases, such as heart failure, uncontrolled coronary heart disease, cardiomyopathy, uncontrolled arrhythmia,or history of myocardial or cerebral infarction within past six months;
9. Participating in other clinical trials.