Find out which Covid-19 vaccine will be used in adolescents

Pfizer-BioNTech vaccine
The forecast is that teenagers are vaccinated with the immunizing agent from Pfizer. Credit: Carlos Alberto Silva

The Pfizer vaccine, according to estimates by the state secretary of Health, Nésio Fernandes, should become predominant in the National Immunization Plan (PNI) in the next 90 days due to the greater availability of doses. Thus, it opens up the possibility of immunizing adolescents without compromising care for other groups.

This immunizing agent was authorized by Anvisa for the 12 to 15 year-old group in June. Before, only people over 16 could be vaccinated with Pfizer in the country.

In Espírito Santo, the first teenagers to receive the vaccine will be those with comorbidities.

Although authorized in Brazil, the vaccination of adolescents can only be started when at least 90% of subsequent age groups have been immunized with the first dose.


Pfizer was the first manufacturer to announce results of its study in teenagers 12 to 15 years old, in early May, with 100% effectiveness.

According to the results of the combined phase 2/3 study in adolescents, initiated on October 12 of last year, 16 cases of Covid-19 were detected among the 2,260 adolescents involved, all in the placebo group.

In addition to the efficacy data, the vaccine also proved to be safe. And the immunogenicity of the vaccine, that is, its ability to induce an immune response in the body, was almost twice as high in the age group from 12 to 15 years old compared to those aged between 16 and 25 years old.

Upon completion of the study in this age group, the US regulatory agency FDA authorized, in early May, the use of the vaccine in people over 12 years of age. In the United States, Pfizer was already being applied to the entire population over 16 years of age. The United Kingdom and the European Union also endorsed it for use in children under 16 at the end of May. In Latin America, Uruguay was the first country to start immunizing adolescents in June.

In the general population, the efficacy of Pfizer’s Covid-19 vaccine is 95%, but with the Delta variant, it loses some of its ability to stimulate an immune response in the immunized public.


Pfizer’s vaccine uses messenger RNA (mRNA) – acid that is already produced in the human body – to provide protection to the person receiving the immunizing agent, creating antibodies against Sars-Cov-2 (coronavirus). Instead of inserting the attenuated or inactive virus into the body, the immunizer “teaches” the cells to synthesize a protein that stimulates the vaccinated individual’s immune response.

The mRNA vaccine, according to the Pfizer website, simulates the process that takes place in the body of a person who has actually contracted that disease, but in a way that does not allow the person being vaccinated to become infected – just by educating the body on how to respond to that disease. invader.


Pfizer and BioNTech have also started studies to verify the safety and efficacy of the immunizing agent in the age group between 6 months and 11 years. The first results of the survey are expected to be published by the end of this year.

Butantan, in turn, already has research results for the application of Coronavac – a vaccine produced by the institute in the country – in children aged 3 to 12 years and asked Anvisa to include this age group in the package insert for the immunizing agent. The request was denied by the federal agency, on the grounds of lack of data and a small study group, but the decision could be reviewed.

This refusal, according to Nésio Fernandes, frustrates the expectation of being able to vaccinate children and postpones the beginning of the action, but it is not a decision that affects, for example, the vaccination schedule for adolescents.

In Espírito Santo, there is a demand for 360,000 adolescents to receive the vaccine, but the definition of the strategy is up to the Ministry of Health. Nésio Fernandes hopes to be able to start serving this public in September, although now the third dose (D3) for the elderly and immunosuppressed is primarily from Pfizer.

Asked if it will be possible to carry out the two actions, the secretary assures that one does not make the other unfeasible. But, most likely, adolescents who do not have comorbidities will start receiving care towards the end of next month, after the start of the booster dose in the elderly.

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