The company used flow cytometry to quantify CD4+ helper T cells and CD8+ killer T-cell responses based on the haptenized SARS-CoV-2 spike protein used in the vaccine. They found that immunization with BVX-0320 at the 3-µg and 10-µg level stimulated immune memory and killer cells. According to the company, the strength of CD4+ and CD8+ T-cell responses have the potential to confer much longer protection than other vaccines.

BVX-0320 is based on technology developed by BioVaxys, which leverages haptens to make targets more recognizable to the immune system. The process of haptenization "teaches" a patient's immune system to recognize and make target proteins more "visible" as foreign, thereby stimulating an immune response.

The preclinical study was conducted by Charles River Laboratories under contract with BioVaxys. After two injections of the vaccine, 96.4% of mice developed positive antibody responses at week six. In a separate study, conducted at the Ohio State University Wexner Medical Center, mouse sera are being evaluated for the ability to inactivate live SARS-CoV-2 virus. The results from this study are expected later this month.