COVID-19 vaccination remains a subject of intense research, even if it doesn’t have the urgency felt at the height of the pandemic. One domain of interest is the progression of mucous vaccines that can be administered through the nose. These nasal vaccines are affordable to produce, easy to buy and transport, and useful in places where access to a skilled medical staff of workers is limited.
Now, scientists have developed a live attenuated SARS-CoV-2 vaccine for the nose that shows promise in the mucous membranes of the nose, mouth, throat and lungs and confers greater immunity than vaccines injected into muscle.
This painting is published in Nature Microbiology in the article “Live attenuated vaccine sCPD9 elicits systemic and upper mucosal immunity than SARS-CoV-2 variants in hamsters. “
In the fall of last year, two nasal vaccination formulations opposed to COVID-19 were approved for use in India and China, yet to seek approval in Europe. These are modified adenoviruses that self-attenuate.
The benefits of a nasal vaccine go far beyond a want-free option. When a vaccine is injected, it induces immunity basically in the blood and body. In this case, the immune formula does not stumble and fights coronaviruses until relatively recently. in an infection, because they enter the frame through the mucous membranes of the upper respiratory tract. “So this is where we want local immunity if we want to intercept a respiratory virus early on,” explained Jakob Trimpert, PhD, leader of the study organization at the Institute of Virology at Freie Universität Berlin.
Scientists tested the efficacy of the newly developed COVID-19 intranasal vaccine in hamster models. They analyzed “immune responses and preclinical efficacy of BNT162b2 mRNA vaccine, Ad2-spike adenoviral vector vaccine, and live attenuated candidate vaccine sCPD9 in Syrian hamsters. “
After double vaccination with live attenuated vaccine (A), the hamster-style nasal mucosa is well and has virtually no readjustments of SARS-CoV-2 (B). The mixture of live vaccines and mRNA (C) is also very effective, however, the virus still discovers small attack sites (stained brown) in the nasal mucosa (D). In comparison, double intramuscular vaccines are much less effective in terms of protecting the nasal mucosa (E F and G H). top layers of tissue. [Anne Voß, Institute of Veterinary Pathology, Freie Universität Berlin] They found that after two doses of the vaccine, the virus may no longer reflect in the body-style. “We observed strong activation of immunological memory and mucosal membranes were doing very well through the maximum concentration of antibodies,” Trimpert explained. The vaccine, therefore, could also particularly reduce the transmissibility of the virus.
In addition, the scientists compared the efficacy of the live attenuated vaccine with that of vaccines injected into the muscle. To do this, they vaccinated the hamsters twice with the live vaccine, once with mRNA and once with the live vaccine, or twice with a vaccine based on mRNA or adenovirus. Then, after the hamsters became inflamed with SARS-CoV-2, they used tissue samples from the nasal lining and lungs to see how well the virus could still attack mucous cells. We also decided on the extent of the inflammatory reaction using single-cell sequencing.
The live attenuated vaccine performed more than other vaccines. The most productive coverage against SARS-CoV-2 was provided through dual nasal vaccination, followed by the muscle injection mixture of the mRNA vaccine and the following nasal management of the live attenuated vaccine.
The next step is the protection test: Researchers are participating with RocketVax, a Swiss startup founded in Basel, in a phase I clinical trial in humans.