Anvisa authorizes inclusion of booster dose against covid in Pfizer's package insert

This Wednesday (24), the National Health Surveillance Agency (Anvisa) approved the change in the package insert for the ComiRNAty vaccine (Pfizer/BioNTech) against covid-19. Now, the use of the booster of the immunizing agent, developed by the pharmaceutical company Pfizer, in Brazil, is officially authorized. Before, the application was off label — outside the package insert —, which is allowed. This is a strategy used in times of emergency, such as a pandemic, or when alternatives are lacking.

Before approving the change, Anvisa evaluated the data and studies presented by the North American laboratory. In the process, “it concluded that scientific evidence demonstrates safety and efficacy for the application of the booster dose of Pfizer”, explained the agency, in a statement.

Anvisa authorizes change in Pfizer’s vaccine package insert to include the booster dose against covid-19 (Image: Reproduction/Pfizer Brasil)

Change in package insert

The application should take place at least 6 months after the individual completes the two-dose vaccination schedule, according to the package insert. In addition, the reinforcement is only available for those over 18 years of age. Finally, “the booster indication approved by Anvisa is for homologous use, that is, booster for people who received ComiRNAty in the first immunization”, according to the agency.

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The indication of the package insert, approved by Anvisa, “is based on clinical studies and results developed by the laboratory, which in this case evaluated the administration of the booster in volunteers initially immunized with the two-dose regimen of Pfizer”.

According to the Ministry of Health, ideally the booster of the vaccine against covid-19 should be done with Pfizer’s formula, regardless of the other immunizing agent received. For those who received other vaccines, heterologous vaccination with ComiRNAty will occur. So far, this usage is off label.

After all, why release reinforcement to the majority of the population?

If Pfizer’s initial vaccine plan was to use just two doses, understanding why the booster was released is important. During Anvisa’s analysis, “data from scientific studies that indicate a decrease in neutralizing antibodies and some evidence of decreased efficacy were observed [da vacina] against covid-19. Another data considered was the emergence of variants of the SARS-CoV-2 virus, including the Delta variant”.

Is it booster or third dose?

Here, it is important to clarify that the extra dose is a booster, which should not be confused with a third dose. According to Anvisa, “the booster dose is intended to maintain or even improve the immunity generated by the primary vaccination course, preventing the immune response in the body from starting to diminish after a long period”.

Unlike this concept, talking about a third dose would only make sense in the case of an immunizing agent in which three doses of the vaccine are needed for the individual to be immunized. According to Anvisa’s understanding, “there are no vaccines against covid-19 in Brazil with a three-dose regimen”.

Janssen and AstraZeneca also want to change the package insert

At this time, the agency is analyzing two other requests for the inclusion of the reinforcement in the package insert, one from AstraZeneca and one from Janssen. “In the case of Coronavac, also in use in Brazil, there is still no request from the laboratory to evaluate booster doses”, informs Anvisa.

Source: Anvisa

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