COVID-19: Brazil-made nose spray may be available by 2022

A vaccine in the form of a nose spray against COVID-19 is being developed by researchers from the University of São Paulo (USP) in collaboration with the Federal University of São Paulo (Unifesp) and the Oswaldo Cruz Foundation (Fiocruz). Currently in its study phase, the inoculation is pledged to come at a low cost, protect against variants, and block the new virus already in the nose. It is expected to be available by the end of 2022.

“You already start inducing a response in the nasal epithelium as well as the production of an antibody that plays an important role in the mucous membranes—the secretory IgAs [Immunoglobulin A],” said study coordinator Professor Jorge Elias Kalil Filho from the USP Medical School, who is also head at the Clinical Immunology and Allergy Laboratory of the Hospital das Clínicas.

In addition to its innovative inoculation method—nasal, rather than intramuscular—the vaccine also stands out due to its antigen. “Instead of using the spike from the Wuhan virus, we’ll use only the RBD [receptor-binding domain] from the four variants of concern,” Kalil Filho said. The spike protein, Fiocruz declared, is linked to the pathogen’s capacity to enter human cells and is one of the main targets of the neutralizing antibodies produced by the human body to stop the virus.

The researcher went on to explain that the antigen will carry protein fragments that stimulate a longer cellular response than those mediated by the neutralizing antibodies. “We monitored 220 people who had the disease, studied all of the virus’s genome, and selected the fragments that theoretically induce a good cellular response,” he said.

The vaccine, therefore, should include fragments capable of killing the cell in case it becomes infected. “If the virus enters the cell, the only thing you’ll be able to do is use cells called cytotoxic CD8, which kill the infected cell,” Kalil Filho pointed out. The spray should therefore contain the so-called T CD8+ cytotoxic lymphocytes, which eliminate sick cells, as well as T CD4+ lymphocytes, which help produce antibodies and create a cytotoxic response.

Another innovation is the creation of a sort of nano-particle that adheres to the mucous membrane of the nose. “The mucous membrane has a large number of cilia that won’t let anything stick, but we have found a way to introduce a specif formula through which we can induce an important response from the mucous membrane,” he added.

Regarding its cost, Kalil Filho noted it should be priced at around five dollars, but further analysis is required. “We have some laboratories producing recombinant proteins, but it’s still rather incipient, so we’re talking with pharmaceutical companies to see if we can find one capable of producing with high quality.”

The nose-spray vaccine may serve as a boost to existing intramuscular doses. “When the spray is ready, a significant portion of the world population is likely to be vaccinated. I believe it will work as a booster dose,” the specialist stated.