The Development of a COVID19 Oral Vaccine Consisting of Bacillus Subtilis Spores

Bacillus subtilis is regarded as safe organism by The Food and Drug Administration and it is presented in most food sources. Preliminary experiments have shown that the genetically engineered Bacillus subtilis can express and display receptor binding domain of spike protein of the SARS-COV2 on its spore coat, thus successfully induce the secretion of cytokines of human cells in vitro. Previous experiments also successfully demonstrated that a increased detection of neutralizing IgG and igM levels in mice after oral administrated with the Bacillus subtilis. This suggests that the transgenic spores of Bacillus subtilis have successfully activated the immune system, producing high-affinity neutralizing antibodies and memory B cells. Furthermore, no adverse effects were shown in all the mices. The engineered Bacillus subtilis will be further studied in a human trials through oral administration to test its safety and the immune effect resulted in human bodys.

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.

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 30 days before the first dose