Covid-19: all vaccines administered in Brazil are effective

Research by the Oswaldo Cruz Foundation (Fiocruz), which analyzed the four vaccines administered in Brazil against covid-19, from January to October 2021, shows that they all provide a great reduction in the risk of infection, hospitalization and death.

Considering the serious outcomes (hospitalization or death) in individuals aged between 20 and 80 years of age, protection varied between 83% and 99% for all immunizers. In the population under 60 years of age, all vaccines provide protection above 85% against the risk of hospitalization and above 89% against the risk of death.

The information is in the first edition of the bulletin on the effectiveness of vaccines against covid-19 in the Brazilian population, from Fiocruz's Vigivac project, published on Thursday (9).

The analyses, coordinated by researcher Manoel Barral, from Fiocruz Bahia, were carried out using anonymous individual information from the databases of the National Vaccination Campaign against Covid-19 (Covid-19 Vaccination), Flu Syndrome Notifications (e-SUS Notifica) and Reports of Severe Acute Respiratory Syndrome (SRAG 2020 and 2021; SIVEP-Influenza).

CoronaVac

According to the survey, CoronaVac showed high effectiveness for the population between 18 and 59 years of age, ranging from 89% to 95% and from 85% to 91% for deaths and hospitalizations, respectively. However, there was a significant drop in effectiveness in people aged 60 years and over. In the range between 60 and 69 years of age, protection against severe forms of the disease was 81%, reaching 64% in people over 80 years of age.

The researchers say that this reduction in protection in the elderly can be explained by several factors, but mainly by the longer time since the last vaccination and by the greater vulnerability of the group that received the immunizing agent, since CoronaVac was the most used among the elderly and priority professionals , as in the health and safety area, which are more exposed to contagion. In addition, the vaccine was administered during a period of increased virus circulation.

AstraZeneca

AstraZeneca was the most used vaccine in the country, according to the bulletin. The results for the adult population up to 59 years of age showed 99% effectiveness of the immunizing agent against deaths. The drop in effectiveness also accompanied the increase in the age group. In the group of people between 60 and 69 years of age, protection against infection was 89%, reaching 82% in individuals over 80 years of age. With regard to deaths, people over 80 years of age had 91% protection, a little lower than the other groups aged 60 to 69 and 70 to 79 years of age, which had 97% and 93%, respectively.

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Analyzes for the adult population aged 59 and under who received Pfizer showed that protection remained above 96%. Protection against death and hospitalization for covid-19 in this group was 99%. The researchers point out that Pfizer was administered to the younger population and at an epidemic time with less circulation of the virus, which could favor the effectiveness of the vaccine.

Janssen

In the adult population up to 59 years of age who received Janssen, the analyzes indicated protection against death from 78% to 94%. Protection against hospitalization was between 88% and 91% and against infection the effectiveness was from 68% to 73%. For the elderly population, it was possible to safely calculate effectiveness only for the population aged 80 years and over, who had protection against death by 91% and against hospitalization by 93%.

Text translated using artificial intelligence.