MedUni Vienna delivers promising data to the Omicron variant vaccine, which could protect people against all known variants of the SARS-CoV-2 virus
The preclinical data for a vaccine developed at MedUni Vienna to protect against SARS-CoV-2 indicates effective protection against all SARS-CoV-2 variants known to date, including Omicron.
This vaccine works so far even for people who have not yet built up any immunity as a result of vaccination – otherwise known as non-responders.
This latest antigen-based vaccine design targets the receptor binding domains (RBD) of the SARS-CoV-2 virus and induced a robust and uniform RBD-specific IgG antibody response in animal models and in human tests.
The antibody response developed from this Omicron variant vaccine can prevent the virus from entering the body’s cells, so that infection cannot occur, even giving immunity for previous “non-responders”.
Results were based on decades of experience from allergy research
Published in the journal Allergy, the researchers used a combination of the original coronavirus vaccine and hepatitis B vaccine to generate this potential Omicron variant vaccine.
The SARS-CoV-2 subunit vaccine (PreS-RBD) is based on 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. These assist as immunological carriers for each other, which can strengthen the immune response in the recipient.
Currently available genetic SARS-CoV-2 vaccines induce mainly transient IgG1 antibody responses, whereas the PreS-RBD vaccine can additionally 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 in 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-neutralising titers were higher than those in a random sample of individuals fully immunised with two vaccinations of currently registered vaccines or than those of COVID-19 convalescents – such as individuals who had previously had COVID-19.
Overall, the Omicron variant vaccine may even be effective in people who have not previously responded to vaccination – known as “RBD non-responders” – as they can receive additional T-cell support from the PreS portion of the vaccine. This could indicate this new potential vaccine is more advanced and protective than the ones that have been formerly developed.
20% of people recovered from COVID-19 failed to form RBD-specific antibodies – putting them at risk of re-infection
Inspired by decades of experience in allergy vaccine design, previous work on allergy vaccines and clinical trials also conducted with PreS-based allergy vaccines have proven the safety of this new PreS-based vaccine design, even after multiple repeats.
Study leader Rudolf Valenta, finalised: “The PreS-RBD vaccine has the potential to induce sterilizing 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.
“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 sterilizing 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 neutralizing antibodies.”
If the researchers attain sufficient support and funding for this vaccine, the first clinical trials required for approval could be carried out in 2022.
