The scenario of facing COVID-19, caused by the SARS-CoV-2 virus, represents one of the greatest public health challenges on a global scale in this century. In this short period of time, due to the demand for advances towards a cure and expansion of access to diagnosis, 11 vaccines have been approved for emergency use by the WHO (World Health Organization) in order to meet the current need and respecting the strict criteria of safety, efficacy and quality of immunizers (1). In Brazil, six vaccines against COVID-19 are currently available, four of them approved for emergency use by ANVISA and two others with exceptional export authorization (2).
The vaccines approved by ANVISA and available in Brazil against COVID-19, have different technologies (inactivated virus, adenovirus or messenger RNA), which generate a similar response in immunized individuals: the production of neutralizing antibodies able to recognize and eliminate the SARS-CoV-2 virus. However, the stimulation of immunity against COVID-19 is a complex process that is influenced by different factors and may vary from one person to another.
In the development of prophylactic (preventive) vaccines, the main target of studies under development is the production of neutralizing antibodies, which prevent the virus from entering human cells. However, it is not possible to estimate the protection of an immunizer by the presence of antibodies alone. Protection against disease can also occur through the activation of other cells in the immune system, such as T-cells. These cells are crucial for developing long-lasting protection, because they are able to activate memory cells, which in turn teach the immune system to recognize and eliminate the coronavirus whenever it is present in the body. Furthermore, studies show that immune responses generated by T cells are less affected by SARS-CoV-2 mutations than responses generated by vaccines based on neutralizing antibody production, suggesting that protection generated by T cells are effective against variants (3).
Vaccination has been a key tool in reducing the number of deaths and severe cases from COVID-19. According to research conducted by the Federal Institute of Paraíba, the advance of vaccination against COVID-19 in Brazil has reduced 96.44% of the number of deaths caused by the disease (4). And, despite these numbers representing an effective public health action, the circulation and mutation of the SARS-CoV-2 virus still poses numerous challenges for the health system and generates relevant socioeconomic impacts. Therefore, the circulating variants of the virus are under surveillance by numerous countries, mainly due to the possible relationship with the sudden increase in new cases, the severity of the disease, and the detrimental effects on the effectiveness of available and developing vaccines.
In Brazil, the number of deaths exceeds 670,000 cases since the beginning of the pandemic, with an average increase of 34% in the number of new cases compared to the last month (data referring to June/2022) (5).
The vaccination coverage in the country is 77.89% of the total population, and the distribution of booster doses to the population is recommended by the Collegiate Board of Directors of ANVISA, aiming to extend the protection, avoiding the drop in the level of antibodies induced by vaccines and reducing the chance of infection in case of new variants (6). These guidelines highlight the importance of investigating the longevity of immunization in the population and the need for new approaches aimed not only at prevention, but also at treatment of COVID-19.
ImmunoTera has been working to find therapeutic solutions to address COVID-19, which address the needs, primarily, of patients who already have the disease. The platform under development aims to induce an immune response based on T cells, preventing the action of the virus through the activation of the immune system, as well as aiming at the treatment of patients who are infected with the SARS-CoV-2 virus.
Pre-clinical trials have been conducted in recent months, and the vaccine platform has demonstrated partial protection in the treatment of animals infected with SARS-CoV-2, when compared to untreated groups. The proposal is innovative and addresses a therapeutic strategy for patients affected with the severity of the disease, providing a better recovery and quality of life. It is worth noting that ImunoTera believes that vaccination is the most effective methodology to combat the spread of the disease and the emergence of new variants of COVID-19, and therefore guides and encourages the administration of vaccines that are available for free through the SUS (Brazilian Unified Health System).
References
1. COVID-19 Vaccines with WHO Emergency Use Listing. Disponível em: https://extranet.who.int/pqweb/vaccines/vaccinescovid-19-vaccine-eul-issued
2. Vacinas – Covid-19. Disponível em: https://www.gov.br/anvisa/pt-br/assuntos/paf/coronavirus/vacinas
3. de Castro, Mateus V., et al. "Monozygotic twins discordant for severe clinical recurrence of COVID-19 show drastically distinct T cell responses to SARS-Cov-2." medRxiv (2021).
4. Araujo, Fernando HA, and Leonardo HS Fernandes. "Lighting the populational impact of COVID-19 vaccines in Brazil." Fractals 30.03 (2022): 2250066.
5. On the rise, moving average of Covid deaths in Brazil approaches 200 per day. Available at: https://g1.globo.com/saude/coronavirus/noticia/2022/06/27/em-alta-media-movel-de-mortes-por-covid-no-brasil-se-aproxima-de-200-por-dia.ghtml
6. Map of Covid-19 vaccination in Brazil. Available at: https://especiais.g1.globo.com/bemestar/vacina/2021/mapa-brasil-vacina-covid/
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