Vaccination against COVID-19: where do we come from, where are we and where are we going?

• Grant number: 23/01925-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): December 01, 2023
• Effective date (End): November 30, 2025
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luis Carlos de Souza Ferreira
• Grantee: Jessica Pires Farias
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

COVID-19 is a viral infection with high transmission potential and broad clinical spectrum, caused by the SARS-CoV-2 virus. The first case of the disease was identified in Wuhan, China, in 2019 and it only took a few months for it to cross continental borders and then be recognized by the World Health Organization (WHO) as a pandemic. Over the more than three years that followed this advent, scientific study was imperative for the understanding of human pathophysiological and immunological mechanisms, as well as the elucidation of viral behavior for the development of vaccine technologies that would allow control of the disease. Today, more than 70% of the world's population has been vaccinated against COVID-19, but the constant appearance of new viral variants with high rates of genetic mutations that allow vaccine escape is a scientific bottleneck against the appearance of new outbreaks. Thus, studies that allow the real-time monitoring of the population's vaccine immune response against new viral variants can help in the understanding and rapid development of new vaccine antigens capable of controlling new epidemics of the disease. The main of this project is to verify the performance of vaccine regimens administered in Brazil against COVID-19 against circulating SARS-CoV-2 genetic variants/subvariants and, in view of this response, propose the updating of antigens for new vaccine formulations. This goal should be achieved through the combination of two methodological approaches. The first focused on carrying out an observational clinical study in a cohort with individuals from the municipality of Barreiras, Bahia, where the following will be verified: a) the longevity and quality of immune responses induced by current vaccination policies and b) genomic sequences of circulating viruses in the study period. Personal data and nasopharyngeal secretion and blood samples collected between May 2020 and May 2024 will be analyzed. The second methodological strategy of this project is focused on the development of a computational study to identify promising antigens that can improve the induced immune response by vaccination against SARS-CoV-2 in a scenario of genetic escape mutations. It is also intended to design new antigens with vaccine potential through the analysis of conserved epitopes (for B and T cells) and validate them experimentally with genetic vaccines capable of encoding an ideal antigenic candidate and monitoring of specific immune responses induced in animals. It is expected that the combination of these approaches will generate more accurate information on the performance of the vaccine regimens against COVID-19 used in the country, with immediate application in public policies for vaccination and disease control and that will consequently allow the development of antigens. Innovative escape mutation-proof vaccines, in view of the high capacity for antigenic variation of the virus that causes COVID-19. (AU)