Anvisa approves emergency use of Pfizer’s bivalent vaccines against Covid-19

The National Health Surveillance Agency (Anvisa) unanimously approved this Tuesday (22) the emergency use of two Pfizer bivalent vaccines against Covid-19.

There are two updated immunizers that include sublines of the Ômicron variant of the coronavirus and should be used as booster doses against the disease.

The decision was taken in a vote by the Collegiate Board of Anvisa in an extraordinary meeting held at night. For the evaluation, the agency had the collaboration of medical societies.

The case rapporteur, Meiruze Freitas, voted for approval and was accompanied by directors Daniel Ferreira, Romison Mota, Alex Campos and by the director-president of Anvisa, Antonio Barra.

understand the process

Pfizer submitted to Anvisa two requests for temporary authorization of emergency use for new bivalent versions of the vaccine. In both requests, the pharmaceutical company requires the indication of the bivalent vaccine for application as a booster dose in the population over 12 years of age.

According to Pfizer, the purpose of reinforcement with the bivalent vaccine is to provide greater protection against the variants of Ômicron, which circulate in Brazil, when compared to its monovalent version currently registered in the country, the vaccine technically called Comirnaty.

The first application, referring to the bivalent with the subvariant Ômicron BA.1, was submitted in August. During the analysis, Anvisa asked Pfizer to send additional information on two occasions, which were complied with by the pharmaceutical company.

The second application considered a version of the vaccine that contains subvariants BA.4 and BA.5, in addition to the original vaccine strain. In this request, made in September, a request for additional data was made to the pharmaceutical company, which was presented, according to Anvisa.

Upgraded booster generates superior immune response

Reinforcement with Pfizer’s bivalent vaccine against Covid-19, which also includes Ômicron’s BA.4 and BA.5 sublines, presents a significantly superior immune response compared to vaccination with the pharmaceutical’s original immunizer. The information was disclosed by Pfizer on November 4th.

According to the release, updated data from a phase 2 and 3 clinical trial demonstrated a robust neutralizing immune response one month after a booster dose of the bivalent vaccine. The generated immunity was accompanied by a similar safety and tolerability profile between the two vaccines.

“These results reinforce previously reported baseline clinical data measured 7 days after a bivalent vaccine booster dose, as well as preclinical data, and suggest that a 30 µg booster dose of the adapted bivalent vaccine may induce a higher level of protection against Ômicron’s BA.4 and BA.5 sublines than the original vaccine,” the statement reads.

Relevance of monovalent vaccines

The development of updated vaccines seeks to contemplate the mutations suffered by the coronavirus throughout the pandemic. The first generation of vaccines was developed from the original strain of the virus, which was circulating at the beginning of the pandemic, in 2020.

Although the emergence of variants of the coronavirus has led to a reduction in the effectiveness of monovalent vaccines against symptomatic infections, immunizers are still effective against the disease in its severe form and deaths, as long as the doses are taken as recommended by the Ministry of Health (see the scheme below 🇧🇷

Vaccine follow-up studies indicate that booster doses of monovalent vaccines restored protection against serious Omicron-associated outcomes. This protection diminished over time with some age-related differences, and particularly during a period of predominance of BA.4 and BA.5 subvariants.

Understand the booster dose schedule

Scientific studies point out that the body increases the immune response against the coronavirus through booster doses against the disease. The application of booster doses in the country follows guidance from the Ministry of Health.

Currently, the first booster dose for those who started the vaccination schedule with AstraZeneca, Pfizer or Coronavac is recommended for people over 12 years of age and should be administered four months after the second application. The second, at the moment, is recommended by the Ministry of Health for the population over 40 years of age and health workers regardless of age and should be administered four months after the first booster dose.

For those who started the vaccination scheme with the single application of Janssen , the recommendation is a booster given two months after starting the vaccination schedule; and the other two that must comply with the four-month interval between one and the other. For the immunocompromised population aged 12 to 39 years, who started the vaccination schedule with AstraZeneca, Pfizer or Coronavac, a booster dose is recommended four months after the additional one.

For immunocompromised individuals who started the vaccination schedule with Janssen, two booster applications are indicated after the additional dose, with an interval of four months between them. Recommended booster vaccines are those from Pfizer, AstraZeneca or Janssen — these can be used for people aged 18 years or older. For adolescents between 12 and 17 years old, the Pfizer vaccine should preferably be used. If it is not available, the Coronavac vaccine can be used in the booster dose, according to the ministry.

Data from the National Immunization Program (PNI) show that 69 million people are in arrears with their first complementary dose. The Ministry of Health points out that studies have been carried out that demonstrate that the body’s ability to respond, called immunogenicity, after the application of alternate immunization boosters is adequate.