Vaccines for intranasal application, by means of spray, are the great bet of science to stop not only the infection, but also the transmission of the virus. coronavirusin addition to being easier to adapt to the new variants that appear all the time, increasingly transmissible.
So, what is missing for this important step towards the end of the Covid-19 pandemic? In an interview with R7researchers working on the development of nasal spray vaccines in Brazil explain that the main barrier is the lack of investment.
The coordinator of the study underway at InCor (Instituto do Coração, Hospital das Clínicas, Faculty of Medicine, USP), in São Paulo, Jorge Kalil, says that even the scientists’ permanence in the study is hampered by the lack of funds.
“For us to be able to pay people to work, it has to be in the form of a grant, values that are very low, there is no guarantee of employment. So if [o pesquisador] gets a job with a formal contract, he leaves”, says Kalil
Despite recognizing that the resources made available by the technology and innovation centers have been important for his research, the study coordinator emphasizes that this is not the rule in the country.
“Brazil’s resources for research are small and there is also no habit of private industries to participate in the development process. [dos estudos]they usually take something that has already been fully developed abroad”, says Kalil.
The nasal spray vaccine developed by researchers at UFMG (Federal University of Minas Gerais) follows in the same vein, according to Dawidson Assis Gomes, professor of biochemistry at the Department of Biochemistry and Immunology at the Institute of Biological Sciences at the institution.
“The main difficulty for the development of our vaccine has been the lack of resources for a faster progress. Our project has not had any public or private funding so far, we are developing our technology only with investment from the laboratory itself”, says Gomes.
The UFMG vaccine is still in the pre-clinical phase with animal tests. In the case of the immunizer developed by InCor, on the other hand, the research on animals has already been completed, but there is no industrial support for the inputs to be manufactured in Brazil and, thus, the vaccine passes to the human testing phase.
Understand how nasal spray vaccines work
Vaccines for intranasal application are seen as the main bet to reinforce vaccination against Covid-19 because they attack the virus right at its main gateway into the body: the nose.
In addition, the spray immunizer is also capable of producing immunoglobulin A (IgA), an antibody that plays an important role in fighting the virus in mucous membranes, such as the nose, where Sars-Cov-2 can continue to replicate and be transmitted to more people even if the infected individual is asymptomatic. IgA is rarely produced in injectable vaccines.
According to biochemistry professor Dawidson Assis Gomes, vaccines for intranasal application are also cheaper to produce and transport, as they can be moved at room temperature, unlike conventional immunizers that need special refrigeration.
“They are safer and more convenient to administer. The person can medicate himself, as we do for the application of medication by nasal sprays, such as for allergic rhinitis or asthma”, highlights the specialist.
Vaccines for intranasal application developed in Brazil
The vaccine being developed at UFGM uses synthetic peptides, which are small parts of the virus’s proteins, to induce the production of antibodies against Sars-Cov-2.
“Our formulation already takes into account the variants that are appearing. The use of peptides facilitates the adaptation of the formulation, in case a variant escapes vaccine protection”, says the researcher.
The technology used for the production of the vaccine is entirely national, which eliminates the need to import materials and inputs, facilitating large-scale manufacturing in Brazil.
“The success we are having so far shows that our technology is exceptionally cost-effective and that we are very concerned about developing a product that can be affordable not only for our country, but also for low-income countries,” says the Gomes.
The spray vaccine developed by InCor scientists, under the coordination of Professor Jorge Kalil, uses the Sars-Cov-2 RBD protein, unlike vaccines for intramuscular application, which use the Spike protein.
“What really matters for the induction of neutralizing antibodies is a small portion of the RBD protein, which is here [onde o vírus] binds to the human cell receptor in order to penetrate. And all the variants of concern had mutations in RBD,” explains Kalil.
In addition, for the preparation of the immunizer, a bioinformatics system was also used to select 36 proteins within the Sars-Cov-2 viral genome capable of stimulating T cells, which are responsible for producing the cellular response against the infection.
“With this we made a hybrid protein that has RBD, plus cell fragments that stimulate T cells. [Além disso]we can change the RBB according to the variant by circling, [adaptando a vacina]. Our idea is to do it for vaccinated people, so it will serve as a booster dose in the nose to avoid not only the disease, but the infection, that is, that the virus does not keep multiplying in the nose even if it does not cause disease”, highlights Kalil. .
The main obstacle to the study at this point, however, is access to the technology used to produce the protein. The team is evaluating the purchase of the service abroad but, according to the researcher, there is a worldwide overload in the laboratories that carry out this type of development.
“We started working with this intranasal vaccine proposal in March 2020 and for that we knew that we would not be the first vaccine [a ser utilizada]because the big companies had already launched into vaccines using the platforms they already had at their disposal”, says Kalil.