In Animal Trials Successful: Is a Nasal Covid-19 Live Vaccine Coming as a Booster Vaccination?

"A new generation of mucosal vaccines (vaccines administered via mucous membranes and particularly effective there; note) against the constantly evolving SARS-CoV-2 pathogens would be of great value in combating Covid-19. In previous studies, our research groups developed a viral vector vaccine based on a Newcastle Disease Virus (NDV) that does not cause disease in humans (...)," the experts wrote in the journal "Frontiers in Immunology". The vaccine virus would express a stabilized spike protein of SARS-CoV-2 as an antigen to elicit a protective immune response.

Advantage of Nasal Vaccines

Nasal vaccines, especially those as live vaccines, should be particularly well-suited to prevent protection against infections with viruses that enter the organism through the respiratory tract. This is the case with SARS-CoV-2. Live vaccines that replicate in a limited manner also have the advantage that after such a vaccination, there is temporary production of antigens and an immune response at the site of administration against an otherwise impending infection.

In the new scientific work, the researchers wanted to investigate the tissue distribution, immunogenicity, and the vaccine protection achieved by the nasally administered trivalent vector vaccine (SARS-CoV-2 variants Wuhan, Beta, and Delta) in mice and golden hamsters. The vaccine was injected inactivated into the animals or the live vaccine was administered nasally. Golden hamsters, for example, were brought together with infected animals after vaccination. In mice, the effect of the trivalent vector live vaccine as a booster immunization after two vaccinations with an mRNA vaccine was also tested.

Live Vaccine Against Corona in Animal Trials: Positive Results

The results were positive: Initially, it was shown that the trivalent vector live vaccine against SARS-CoV-2 underwent only limited further replication and remained mostly confined to the site of application when administered nasally. None of the vaccinated golden hamsters subjected to an infection test became infected. The nasal vaccine was more effective than the injectable variant. The trivalent vaccine also apparently led to cross-immunity with the SARS-CoV-2 Omicron BA.1 variant. In mice, it was shown that the nasal vaccine would be suitable as a booster.

"Overall, these results provided proof of concept for the development of mucosal multivalent NDV-HXP-S vaccines (Newcastle Disease Virus vector vaccines; note) as next-generation Covid-19 boosters," the experts summarized their findings. In the future, using such a vaccine, it would not be necessary to constantly adapt the vaccines to new variants of the Covid-19 pathogens.

(APA/Red.)

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