Covid-19: four vaccines are in advanced testing in Brazil; know details


About 200 vaccines against coronavirus are under development worldwide, according to information from the World Health Organization (WHO). Ten of them are in phase three of research, which indicates the final stage of the studies. With more than 32,000 volunteers, Brazil is the stage for testing four of these substances whose research is already at an advanced stage.

Last Monday (19), WHO updated the list of vaccines and their respective stages of evolution. The list includes 44 vaccines under clinical evaluation around the world, which are in phases 1, 2 or 3, which are like providing for testing in humans. These 44 researches are developing vaccines using four different methods:

Vaccines with advanced research in the world

The immunologist Renato Kfouri, director of the Brazilian Society of Immunizations (SBIm), says that because they are in the testing phase, they are susceptible to failures, but all the results had promising results in previous stages.

Vaccines under test in Brazil

The conduct of clinical research on vaccines is the responsibility of each laboratory, but in Brazil, it must be authorized by the National Health Surveillance Agency (Anvisa). According to the municipality, there are currently four vaccines with registered clinical studies in the country, all of them in phase three. Are they:

  • Oxford (Astrazeneca and Fiocruz) – 10,000 volunteers
  • Coronavac (Sinovac and Butantan) – 13 thousand volunteers
  • Pfizer-Wyeth – 2,000 volunteers
  • Janssen-Cilag (Johnson) – 7,560 volunteers

Brazil is the second country in the world that is receiving more studies, behind only the United States, with five. Kfouri assesses that Brazil was chosen to receive the tests due to its tradition of research in the area and also because it is a country with a large number of infections by SARS-CoV2.

“The virus needs to be circulating easily so that people who have had the vaccines can have contact with it and assess whether or not they have been immunized,” he says. In this scenario, technological investment is practically made by foreign laboratories, and Brazil is only responsible for registering and buying the fruit of this technology. A vaccine must be tested in several countries before being marketed, because people from different continents have different genetic material and experience different natural and social situations. Therefore, the immunizing agent can behave differently in certain situations.

According to Anvisa, two studies are in progress continued submission: Coronavac (Sinovac / Butantan) and the Oxford vaccine (Astrazeneca). The Continuous Submission process allows Anvisa to start evaluating data from already completed research phases while other research steps are being conducted. The objective is to anticipate analyzes that will make the evaluation of the registry more agile.

The Janssen-Cilag vaccine has the study currently paused for the investigation of an adverse event. There is no formal request for registration of covid-19 vaccine in Brazil so far.

As research phases

The director of the Brazilian Society of Immunizations (SBIm), Renato Kfouri, explained for the report what it is and what is the importance of each of these phases of evolution. Phase 1 assesses dose concentration, number of doses and safety, usually with dozens of volunteers involved. Phase 2, with hundreds of volunteers, continues to assess the safety of these vaccines and adds to the verification of the immune response, that is, if antibodies were created for this substance. In phase 3, tested on thousands of people, it is shown whether the substance really works, if the individual is protected. It is the final stage of pre-licensing, where the percentage of protection is demonstrated and also the immunization of subgroups, such as the elderly, children, pregnant women, young people, etc. It is time to check the effectiveness.

“Phase 3 is important, as it was with it that the vaccine’s efficacy profile was discovered. Not only in the different populations, but also for different outcomes: if it is protected for a prolonged period, short, severely, hospitalization is avoided, death is avoided, ”says Kfouri. Within this scenario, it is worth saying that mass testing is a fundamental step for all vaccines.

From the Congress in Focus


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