Our adjuvanted recombinant protein COVID-19 vaccine candidate development program is based on innovative and proven manufacturing technology. It is being developed in collaboration with the US BARDA and with GSK for its pandemic adjuvant platform. 

Latest updated on our vaccine candidate

Developments to date

We are using our expertise to test different formulations of our recombinant protein adjuvanted vaccine to develop the formulation that could help answer today’s current vaccination needs.

Earlier this year we announced the results of our VAT02 Cohort 1 and Phase 3 efficacy trials with our first-generation adjuvanted recombinant protein COVID-19 vaccine candidate, which contains the original parental D614 strain, and we have submitted this data to the EMA to support its marketing authorization. 

On June 13th 2022, we reported data from two trials, VAT02 Cohort 2 and Coviboost VAT013, conducted with our next-generation COVID-19 booster candidate modelled on the Beta variant. We intend to submit these additional data to regulatory agencies to support the marketing authorization of this next-generation vaccine, with the aim of making it available later this year. 

"We are moving to a different phase of the pandemic, when a new range of booster options will be needed. We remain driven by science and the data we have observed for our next-generation booster vaccine is particularly encouraging."

Thomas Trimophe
Executive Vice President, Vaccines

Learn more about our clinical development program

Our phase 2/3 trial for the recombinant booster vaccine candidate

Our phase 3 trial for the recombinant vaccine candidate

How is the recombinant protein vaccine made?

Our recombinant protein COVID-19 vaccine candidate uses the SARS-CoV-2 virus spike protein as the vaccine antigen to help the body recognize and ideally fight off the real virus if a person becomes infected. The spike protein helps the coronavirus get into a person's cells, including those in the lungs.1 Here's how it works:

Discover how our candidate recombinant protein vaccine is designed to work

    1. In the lab, scientists copy the spike protein's DNA sequence, then insert it into a circular piece of DNA called a plasmid. (This is called "recombinant DNA", because it re-combines different segments of DNA.)
    2. The plasmid transports the spike DNA sequence into a specialized virus, called baculovirus, that is used to help manufacture the vaccine.
    3. Meanwhile, specialized cells in the lab are on standby, ready to act as miniature factories. The baculovirus enters these cells, which then churn out copies of the spike protein.
    4. Once the cells have generated enough spike proteins, Sanofi technicians extract them from the mixture, purify them, collect them in large batches, and formulate them before dispensing them into vials.
    5. This candidate vaccine is designed to be used in combination with an adjuvant: a different component of the vaccine that helps alert the body's immune system to the spike's presence and helps stimulate it to create antibodies.
    6. When the vaccine is injected into the body, the spike protein is detected by the immune system, which generates antibodies that can identify and bind to it.
    7. These antibodies are then available to attack the spike protein on the virus surface, if it enters the body, and help stop COVID-19 disease.
    8. The immune system responds to the vaccine and commits the spike protein to memory, so that when the body encounters the full SARS-CoV-2 virus it will remember to generate new antibodies to counter the virus. This type of memory typically allows for a vaccine to generate longer-lasting protection from disease.

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  1. Huang, Y., Yang, C., Xu, Xf. et al. Structural and functional properties of SARS-CoV-2 spike protein: potential antivirus drug development for COVID-19. Acta Pharmacol Sin 41, 1141–1149 (2020). https://doi.org/10.1038/s41401-020-0485-4 Last accessed June 2022

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