The main objective of RBDCOV project is to test the efficacy, tolerability, and safety of a new vaccine against different variants of COVID-19 based on the outstanding data generated using a recombinant protein developed by the consortium partners. Two different clinical trials will be run during the project duration to test the variants recombinant RBD protein vaccine, codifying for Beta and Alpha SARS-Cov-2 variants in paediatric population and in immunocompromised adults. The aim of the project is to focus not only on the current SARS-CoV-2 variants but also in the emerging ones as Beta and Alpha variants. Thus, a continuous monitoring of the new emerging variants will be performed throughout the project to ensure that the platform is prepared to cope with the disease. The platform used for the generation of the vaccines is adaptable to variants and will be ready to include in the design any other potential variant that could appear in short, medium and large term. Preclinical data are already available. The core of RBDCOV consortium has been in close contact to the corresponding agencies and considering Reflection paper on the regulatory requirements for vaccines intended to provide protection against variant strain(s) of SARS-CoV-2, preclinical data supporting the first vaccine candidate can be extrapolated for the vaccines against the new emerging variants. This create a unique opportunity for RBDCOV consortium to generate the first RBD recombinant vaccine to be approved in Europe. This vaccine will be manufactured by an European technological company that will change actual paradigms and allow the really change to One health concept, based on the close relationship between the animal world and the onset of certain infections in humans.