Oral Neutralizing Antibody Booster for Post-vaccinated People With COVID19 Vaccine

Human Pilot Test of an Oral Neutralizing Antibody Booster for Post-vaccinated People With COVID19 Vaccine

This is a study trial to assess the effectiveness of the immune response stimulated by the genetically engineered Bacillus subtilis spore extract which contain Spike protein of the SARS-COV2 on the spore coat.

COVID-19 immunization reduces the risk of COVID-19 and potentially serious complications. In clinical trials, all COVID-19 vaccines currently authorized for use in the United States are beneficial in protecting adults and children 5 years and older against COVID-19, including severe illness. So far, studies looking at how COVID-19 vaccines work in real-world conditions (vaccine effectiveness studies) have shown that they work well. However, it has been reported that most of the antibodies in people who received the second dose of COVID-19 vaccine had been dramatically decreased. Bacillus subtilis (B. subtilis) is a generally regarded as safe organism and it is a common food source. The investigators have used an engineered Bacillus subtilis spore which express and display the spike protein receptor binding domain (sRBD) of the SARS-CoV-2 on the surface. The investigators have proved that it successfully increased the neutralizing antibody against sRBD in unvaccinated mice and human individuals after oral administration. On this basis, the investigators designed and developed an oral antibody booster by extracting the spore surface of B. subtilis. This supplement has the advantage of being stable and effective, free of recombinant plasmid, and can be served as a potential antibody booster to existing vaccines. Mice toxicity and efficacy test was conducted and the experiment proved that the B. subtilis spores extract was effective in inducing immune response, and it was safe and did not cause any significant adverse effect. The B. subtilis spore extract will be further studied in a human trials through oral administration to test its safety and the immune effect resulted in human body.

Volunteers who vaccinated with COVID-19 vaccines for over 6 months will be recruited and will receive 1 capsule of neutralizing antibody booster. Their weight, blood pressure, and the concentration of neutralizing IgG antibody against receptor binding domain of spike protein in SARS-CoV2 will be measured before the oral administration and 14, 28 days after the administration. Number of adverse event from the beginning of the administration to 30 days after the administration will also be recorded.

participants after 6-month vaccinated with COVID-19 vaccine received 1 capsule of B. subtilis spore extract

Bacillus subtilis, a harmless intestinal commensal, has earned in recent years, great reputation as a vaccine production host and delivery vector with advantages such as low cost, safe for human consumption and straightforward administration. The technology team has succeeded engineering Bacillus subtilis with spore coat proteins resembling the proteins of the nucleus and spikes of coronavirus. This product could have a vaccine like activity within the intestinal environment.

To measure the weight changes in kilograms and number of incidence of adverse event from the beginning of the administration to 30 days after the administration

Concentration of Neutralizing IgG antibody against Receptor binding domain of spike protein of SARS-CoV2

To measure the concentration of Neutralizing IgG antibody against Receptor binding domain of spike protein of SARS-CoV2 before the administration and 14, 28 days after the administration

Inclusion Criteria: healthy age over 12 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 COVID-19 over 6 months anti-SARS CoV 2 neutralizing antibody is negative in serum. Exclusion Criteria: pregnant women history of COVID-19 infection or showing COVID-19 infection symptoms having had contact to people with known COVID-19 infection in the last 14 days having fever (> 37.4oC in the last 24 hours), dry cough or feeling tired and having aches and pains, nasal congestion, runny nose, sore throat and diarrhea. positive real time RT-PCR COVID-19 test. persons with autoimmune diseases allergic diathesis or any clinically significant allergic disease (i.e. asthma) any condition that might impair the immune response recent or current immunosuppressive medication any other vaccine application 5 months before the first dose