N-protein vaccine Convacell® is effective against COVID-19: phase 3, randomized, double-blind, placebo-controlled clinical trial

We have developed a Convacell®, 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® to rapidly clear infected cells and provide long-lasting protection against COVID-19. Convacell® 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® is sufficient to provide an immune response. Here we report the finding of the phase III clinical trial of Convacell®. Two groups of volunteers from Russia have been either vaccinated with a single dose of Convacell® 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® has shown a good safety profile. Overall, Convacell® demonstrated highly desirable qualities and good performance as a vaccine and can be considered as valuable COVID-19 preventative measure.