The SARS-CoV-2 virus has been holding the world in suspense for nearly two and a half years. Like other corona viruses, the virus that causes Covid-19 is very changeable. Over the course of the pandemic, the virus has developed several variants, some of which are more infectious or able to partially evade the immune response. As a result, the vaccines we’ve been waiting for so long have also become less effective. A new vaccine could help: Researchers have succeeded in developing a broad-spectrum vaccine against corona viruses. This could also protect against future types of viruses. Contains protein fragments from a total of eight different betacoronaviruses. The combination vaccine promotes the formation of antibodies that target parts of the viral protein that are present in all coronaviruses.
Corona Virus: There are other dangers lurking
A look at the animal kingdom reveals that SARS-CoV-2 isn’t the only coronavirus that could become a problem for humans. There are a number of viruses of this type that could wreak havoc on humans and pose the risk of a new pandemic. Classic vaccine development is reaching its limits here: vaccine development takes a relatively long, albeit accelerated, time, as is the case with SARS-CoV-2 vaccines. When the vaccine is ready, often the virus has already mutated and the vaccine may be less effective.
This is where a vaccine comes into play, which researchers from a team led by Pamela Bjorkman of the California Institute of Technology in the US: “We want to develop a well-rounded vaccine that protects against all SARS-like betacoronaviruses, regardless of the animal coronavirus that will spread to humans. At the same time, this type of vaccine could also protect against current and future variants of SARS-CoV-2 without us having to constantly adapt it.“explains Bjorkman.
The team’s vaccine relies on a nanoparticle as a central building block. This consists of a “sticky” carrier protein with pieces of the viral spike protein mounted on its surface. The researchers called the test vaccine “Mosaic-8”. It uses the binding sites of eight different betacoronaviruses, including SARS-CoV-2, the RaTG13 bat virus, and a form of the coronavirus that has been detected in pangolins.
Broad spectrum vaccine against many viruses
The idea behind this is that the immune system comes into contact with as many viral proteins as possible. So he should be trained on recognition markers and attack points, which are the same for all viruses. This would lead to the formation of antibodies which react mainly to the components of the virus which are the same or very similar in all the viruses used. With these components, there is a high probability that they will be modified only slightly in future variants of the virus.
Preliminary studies with Mosaic-8 showed that the immune system of mice produces more widely effective antibodies after vaccination. In their current study, the researchers vaccinated mice with Mosaic-8, an “empty” nanoparticle or a particle containing only the SARS-CoV-2 spike protein. The team then infected the animals with SARS-CoV-2 and its predecessor SARS. No protein fragments of the latter were included in the Mosaic-8 vaccine. The goal behind this was to find out whether vaccine protection is broad enough to detect even non-contained corona viruses.
Mosaic-8 is also effective against an unknown corona virus
The result gives reason for optimism: “Animals vaccinated with Mosaic-8 produced antibodies that literally recognized every SARS-like betacoronavirus we tested“According to lead author Alexander Cohen of Caltech. None of the animals infected with SARS-CoV-2 got sick. In the test group, which was vaccinated only with the SARS-CoV-2 variant of the vaccine, the animals they contracted SARS and died. Animals vaccinated with Mosaic-8 also did not contract SARS. The researchers were able to show that their vaccine was also effective against a coronavirus that was not contained in the vaccine itself.
Scientists are of the opinion that a vaccine based on the Mosaic-8 model could not only protect against new variants of SARS-CoV-2, but also from corona viruses, which in the future will destroy the species in humans. “Some of these betacoronaviruses used in the vaccine could be closely related to the strain that is causing a new outbreak. We therefore need something that protects against the entire group of viruses – and we think we have found it now”, Then Bjorkman.
Further studies are planned
The next step is to test Mosaic-8 in a Phase 1 human clinical trial. For the moment the focus will be on the safety and tolerability of the vaccine; the efficacy test will then follow in a subsequent study. At the same time, further animal experiments are planned in which, among other things, the protective effect of Mosaic-8 in animals already vaccinated with the common Covid 19 vaccines must be examined. The question underlying this is whether the immune system is capable to relearn and produce the more widely effective antibodies instead of the specialized antibodies that have formed in response to the vaccination that has already taken place.
through the California Institute of Technology