Vaccine against SARS-CoV-2 based on non-infectious replicons

Study on the development of a prototype vaccine against SARS-CoV-2 that can be administered intranasally in a single dose

Interview with Sonia Zúñiga, virologist and researcher at Centro Nacional de Biotecnología del Centro Superior de Investigaciones Científicas (CSIC) about this study. Source:

Description of the Study:

  • Title: Desarrollo de una vacuna contra el SARS-CoV-2 basada en replicones no infectivos.
  • Principal Investigators: Luis Enjuanes, Isabel Sola y Sonia Zuñiga.
  • Centers of Implementation: Consejo Superior de Investigaciones Científicas (CSIC). 
  • Study Population: Trials with mice and hamsters are forthcoming.
  • Study type: Study based on laboratory research. Clinical trial coming soon.
  • Design: Defined RNA replicon, which multiplies the gene dose that triggers protection but complementary technologies are needed for vaccine delivery.

Objectives of the Study:

Principal Objective: To generate SARS-CoV-2 virus in the laboratory by assembling synthetic DNA fragments and to eliminate from its genome the genes responsible for virulence using reverse genetics techniques to introduce attenuating mutations and obtain non-infectious and highly immunogenic derivatives as vaccine candidates against SARS-CoV-2.

Secondary objective: Development of animal models (transgenic mice) for the validation of vaccines and other therapeutic agents against COVID-19.

More about this Study:

It is an original vaccine based on the genetic manipulation of SARS-CoV-2 itself, from which we have derived an RNA replicon that multiplies the gene dose that triggers protection. This vaccine includes mutations of the UK, South African and Brazilian viruses, and probably also of a US variant that has appeared in California and New York.

It is also self-amplifying, which means that the dose of RNA injected can multiply 5,000 times inside the body. It also generates a sterilizing immunity, i.e. vaccinated people not only do not get sick, but also do not become infected and do not transmit the virus.

On the other hand, administration could be intranasal. The mucous membranes (nasal, ocular, respiratory, etc.) are spaces open to the exterior and immunity in these areas is best induced locally, presenting the antigen there. This virus enters our body primarily through the respiratory tract.

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