Abstract: This invention relates to the field of Biotechnology and Medicine. It describes the use of vaccine compositions based on the receptor binding domain of SARS-CoV-2 virus in the treatment of patients recovered from COVID-19 and in subjects vaccinated with vaccine platforms other than subunit vaccines, who fail to develop effective protective immunity or where immunity has decreased over time and a booster with the same vaccine used in primary vaccination is not recommended. Particularly, this use is described for vaccine compositions comprising a covalent conjugate of the receptor binding domain (RBD) and a carrier protein such as tetanus toxoid, diphtheria toxoid and diphtheria toxoid mutant CRM197, vaccine compositions having the RBD as antigen, with or without the immunopotentiator outer membrane vesicles of serogroup B Neisseria meningitidis.

Abstract: This invention is related to biotechnology; in particular, to the field of human health. The described vaccine compositions induce a neutralizing immune response against the SARS-CoV-2 virus. These compositions include a portion of the receptor binding protein of the SARS-Cov-2 virus, as antigen, outer-membrane vesicles of the Neisseria meningitides group B bacteria, as immunopotentiating component, and an adjuvant. The vaccine compositions that are described in this invention are useful in the prevention of infection with the SARS-CoV-2 virus.