New antigen-based vaccine protects against all variants of COVID-19

variants of COVID-19

Results from an Austrian study have illuminated that a new antigen-based vaccine is proficient at protecting people from all variants of COVID-19.

Pioneered by a team at MedUni Vienna, the novel vaccine has demonstrated a robust protection against all known variants of COVID-19 to date, including omicron. The vaccine also safeguards those who have not yet built up any immunity due to vaccination (non-responders) from all SARS-CoV-2 variants.

This new vaccine was developed under the leadership of Rudolf Valenta from the Centre for Pathophysiology, Infectiology, and Immunology. The results of animal models and human tests showed that it effectively targets the receptor binding domains (RBD) of the SARS-CoV-2 virus, resulting in a robust and uniform RBD-specific IgG antibody response that prevents it from entering the body’s cells and causing infection.

This study has been published in the journal Allergy.

Combining vaccines

The groundbreaking vaccine, called Pres-RBD, includes a structurally folded fusion protein consisting of two receptor binding domains (RBD) of the SARS-CoV-2 virus and the PreS antigen from hepatitis B. This combination ensures that both components act as immunological carriers for each other, which increases their immune response. Traditional genetic COVID-19 vaccines predominantly elicit transient IgG1 antibody responses, whereas the PreS-RBD vaccine can induce long-lasting RBD-specific IgG4 antibodies.

The team identified that PreS-RBD-specific IgG antibodies detected in blood and mucosal secretions reacted with all variants of COVID-19. The antibodies induced by the PreS-RBD vaccine more potently inhibited the binding of RBD with its human receptor ACE2. This resulted in their virus-neutralising titers being significantly higher than those in a random sample of individuals who had received two doses of currently registered COVID-19 vaccines or had previously had the disease.

Protection against all COVID-19 variants

“The PreS-RBD vaccine has the potential to induce sterilising immunity to old and new SARS-CoV-2 variants, by preventing infection, by stopping viral replication, and transmission through the inhibition of cellular virus entry,” explained study leader Rudolf Valenta.

The team believes that the vaccine will be even more effective in people who had not previously responded to vaccination – RBD non-responders – as they will acquire additional T-cell support from the PreS portion of the vaccine. An earlier study conducted by the researchers revealed that 20% of people who have recovered from COVID-19 failed to form RBD-specific antibodies, meaning they were at a high risk of catching the virus again.

Following allergy vaccine infrastructure

The team’s new vaccine was inspired by decades of work developing allergy vaccines. Their previous experience experimenting with allergy vaccines and clinical trials conducted with PreS-based allergy vaccines highlighted the safety of PreS-based vaccines.

Valenta concluded: “Our data give us grounds to hope that this readily producible protein-based vaccine antigen will be effective against all SARS-CoV-2 variants known to date, including omicron.

“The vaccine is designed to enable repeated injections to build up sustained sterilising immunity, is suitable for use in all age and risk groups and appears to be superior to currently available vaccines when it comes to inducing neutralising antibodies.”

The team is aiming to perform the first clinical trials of their PreS-RBD vaccine this year if sufficient funding is obtained.


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