Since the coronavirus outbreak, researchers have been trying to develop mucosal vaccines that can be nasally delivered. Now, researchers all the way from Berlin were able to create nasal vaccines and demonstrate their immunity effects.
COVID-19 Nasal Vaccines
With consideration of the way COVID-19 is primarily an airborne and respiratorily transmitted condition, nasal vaccines target the initial entry points, which are the mucous membranes in the nose as well as the mouth, throat, and lungs. They detailed their development in a study published in the Nature Microbiology journal. They describe how the live-attenuated nasal vaccine could be better than those that are injected.
SciTechDaily notes that, in the fall of last year, India and China had already approved two formulations for nasal vaccines. These had adenoviruses that were modified and self-attenuating. Such adenoviruses usually cause gastrointestinal or respiratory conditions. The self-attenuating capacities of the adenoviruses mean that they could poorly replicate or completely halt replication. This, in turn, would stop the disease from being triggered.
Other nasal vaccines across the world are also being developed and tested.
Could Nasal Vaccines Be Better Than Conventional Ones?
Aside from being a mere alternative for those who fear injections, nasal vaccines go beyond this. When a conventional vaccine gets injected into the body, it induces immunity mainly in the blood and throughout the whole body.
However, this means that the detection and combat of the immune system against the coronavirus come relatively late. With this, Dr. Jakob Trimpert, a co-author of the study, a research group leader at Freie Universität Berlin's Institute of Virology, and a veterinarian, notes that there is a need for local immunity if the respiratory virus is intercepted early on.
This means that nasal vaccines have higher efficacy compared to conventional ones, which struggle or fail to reach the mucous membranes.
These COVID-19 nasal vaccines were tested among hamster models. These rodents were established by the team when the pandemic started and are, at present, the most important non-transgenic research model organisms for the virus. This is because hamsters can get infected with the same strains as humans. They also exhibit symptoms that are similar to humans.
As per CNN, the scientists observed that the virus could no longer replicate further after receiving two dosages of the vaccine. Dr. Trimpert explains that they saw a "strong activation of immunological memory" and that the antibodies protected the mucous membranes well. This demonstrated the achievement of sterilizing immunity and illness prevention, which has been a long-sought target.
They also compared the efficacy of this vaccine with muscle-injected ones. Upon doing so, they observed that across all parameters the live attenuated vaccine had better performance. This could be resulted from how the nasal vaccine directly builds up immunity at the entry point. Other than that, the live vaccine also had all virus components, not just the spike protein covered by the typical mRNA ones.
The next step for the researchers would be to test the safety of these nasal vaccines. To do so, they are partnering with RocketVax AG, a Basel-based Swiss start-up.
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