Nasal vaccine is our best weapon against COVID-19

Michael Russell argues that substantial immunity to the SARS-CoV-2 virus is conferred only by nasally administered vaccines.

“The best protection against initial infection is coronavirusCovid-19 disease development, as opposed to just its transmission, would most effectively be achieved by an intranasal vaccine,” said Jacobs, Honorary Professor of Microbiology and Immunology in the University’s Department of Medicine and Biomedical Sciences. Professor Russell says.First author of a paper published in Buffalo The forefront of immunology.

The reason, he says, is that the strongest immunity to COVID-19 comes as a result of infections that occur in the upper respiratory tract and mouth, resulting in mucosal immunity through the secretion of immunoglobulin A (IgA). . antibody.

“That kind of immunity is not well induced by existing injectable vaccines,” says Russell. But rather than protecting against severe illness after infection, which is the goal of current COVID-19 vaccines, mucosal immunity is precisely the kind of immunity that protects against initial infection, he says.

“This all stems from a lack of widespread understanding of how the mucosal immune system works,” says Russell.

Nasal Vaccines: A Better Path to Herd Immunity

Evidence showing that Mucosal IgA antibody According to Russell, it would have a significant impact on the acquisition of SARS-CoV-2, the subsequent course of the disease, and the further spread of the virus.

Vaccines administered through the nose not only induce mucosal immunity to prevent infection in individuals, but also reduce community spread due to circulation of aerosol particles and droplets produced by these upper respiratory tract and oral secretions. You can also.

“Our main point, therefore, is that protection against initial infection (rather than protection against the onset of COVID-19) and protection against subsequent infection with the virus is more effectively achieved by an intranasal vaccine. That’s it,” says Russell.

“In other words, the well-discussed and elusive achievement of herd immunity that is not effectively generated by existing injectable vaccines is more likely to be achieved with mucosal immunity induced by intranasal vaccines.”

Antibodies in mucosal secretions

The paper also found that despite the fact that the antibody response to COVID-19 is almost entirely serum-concentrated, the levels of antibodies circulating in the blood mirror those in mucosal secretions. claims to have been found not to.

On the other hand, mucosal IgA antibodies against SARS-CoV-2 antigens are found in saliva, nasal discharge, tears, tracheobronchial secretions, and even breast milk in infected individuals.

The authors acknowledge that while a number of animal model trials have been initiated to develop intranasal vaccines against SARS-CoV-2, many have not continued beyond the preclinical stage. . In part, they explain, this may be due to a poor understanding of how human and animal mucosal immune systems differ.

“Mucosal IgA antibodies in secretions neutralize the virus much more effectively than circulating IgG antibodies in serum,” says Russell.

The author is influenza vaccine Nasal delivery indicates that this is a viable delivery method for vaccines.

recent articles in Nature reports that about 100 intranasal COVID-19 vaccines are in development worldwide, two of which were approved last week in China and India. However, details of the trials supporting these approvals have not yet been published.

“If only a fraction of the time, effort, and resources applied to the development of first-generation COVID vaccines were applied to intranasal vaccines, the world could now benefit from a widely available intranasal COVID-19 vaccine. You may have,” says Russell.

Jiri Mestecki, professor of microbiology at the University of Alabama at Birmingham, is a co-author of the study.

sauce: University of Buffalo