A vaccine from Austria could protect against omicron

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Promising data was provided by a vaccine study at the Medical University of Vienna.

A Coronavirus vaccine developed at the Medical University of Vienna (MedUni) has shown in preclinical data that it can be effective against all previously known SARS-CoV-2 variants, including omicron, and even in people who have not yet established vaccine protection (non-responders), a release said Tuesday.

The vaccine is a combination of Corona and hepatitis B vaccines. The study was published in the journal Allergy.

The antigen-based vaccine, developed at MedUni Vienna under the study leadership of Rudolf Valenta of the Center for Pathophysiology, Infectiology, and Immunology, targets the receptor-binding domains (RBD) of the SARS-CoV-2 virus and stimulates a robust and uniform RBD-specific IgG antibody response in animal models and human assays.

This antibody response prevents docking and entry of the virus into somatic cells, thus preventing infection.

More excellent protection than with two partial vaccinations

The SARS-CoV-2 subunit vaccine (PreS-RBD) developed at MedUni Vienna is based on a structurally folded engineered protein consisting of two receptor-binding domains (RBD) of the SARS-CoV-2 virus and the PreS antigen from hepatitis B, which serve as immunological carriers for each other and thus enhance the immune response.

Currently, SARS-CoV-2 genetic vaccines mainly induce transient IgG1 antibody responses, whereas the PreS-RBD vaccine can also induce long-lived RBD-specific IgG4 antibodies.

PreS-RBD-specific IgG antibodies detected in blood and mucosal secretions reacted with SARS-CoV-2 variants, including the omicron variant.

Antibodies induced by vaccination with PreS-RBD more potently inhibited the binding of RBD with its human receptor ACE2, and their virus-neutralizing titers were higher than those in a random sample of persons fully immunized with two partial vaccinations of currently registered vaccines or than those of COVID-19 convalescents (i.e., persons formerly ill with COVID-19).

No virus production and transmission

“The PreS-RBD vaccine has the potential to achieve sterilizing immunity against old and new SARS-CoV-2 variants by preventing infection through inhibition of cellular viral entry so that there is also no more virus production and transmission,” explained study leader Rudolf Valenta.

In addition, the vaccine is also expected to work in people who have not previously responded to vaccines (“RBD non-responders”) because they get additional T-cell help from the PreS portion of the vaccine. An earlier study by Valenta and colleagues found that approximately 20 percent of those who recovered from COVID-19 disease failed to produce RBD-specific antibodies and were therefore at constant risk of re-infection.

The release said that the development of this Austrian corona vaccine was strongly inspired by decades of experience in allergy vaccine design. Previous work on allergy vaccines and clinical trials conducted with PreS-based allergy vaccines have shown the safety of PreS-based vaccines, even when used repeatedly.

“Our data give hope that this easily produced protein-based vaccine antigen will be effective against all SARS-CoV-2 variants known to date, including omicron,” said study leader Rudolf Valenta. “The vaccine is designed to enable repeated injections to build sustained sterilizing immunity, could be used in all age and risk groups, and appears superior to currently available vaccines in inducing neutralizing antibodies.” If sufficient funding is committed, the first clinical trials needed for approval could be conducted this year.