ABSTRACT
We have developed a Convacell(R), a COVID-19 vaccine based on the conservative viral nucleocapsid (N) protein. The N protein is evolutionary conservative and is abundantly expressed on the surface of infected cells, allowing anti-N immune response generated by Convacell(R) to rapidly clear infected cells and provide long-lasting protection against COVID-19. Convacell(R) has been demonstrated to be safe and highly immunogenic, creating immune responses lasting over a year, in phase I/II and IIb clinical trials. Phase IIb clinical trial has also demonstrated that a single dose vaccination regimen with Convacell(R) is sufficient to provide an immune response. Here we report the finding of the phase III clinical trial of Convacell(R). Two groups of volunteers from Russia have been either vaccinated with a single dose of Convacell(R) or injected with placebo, and then monitored for incidence of COVID-19 and adverse effects. Anti-N antibody titers at admission were also analyzed, to take into account for potential effects of previous virus encounters. Disease incidence over 6 months results indicate an overall vaccine efficacy of 85.2% (95% confidence interval: 67.4-93.3%). Additionally, Convacell(R) has shown a good safety profile. Overall, Convacell(R) demonstrated highly desirable qualities and good performance as a vaccine and can be considered as valuable COVID-19 preventative measure.