Brazil approves COVID-19 bivalent vaccines

Brazil´s national drug regulator Anvisa authorized on Tuesday (Nov. 22) the emergency use of two COVID -19 bivalent vaccines, produced by Pfizer, to protect against the new coronavirus Omicron sub-variants.

The immunizer will be administered as a booster dose to people 12 years and older, three months after the last booster dose.

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The second-generation bivalent vaccines protect against the original variant of the new coronavirus, from Wuhan Province (China), and also against the latest Omicron sub-variants. The latter is more transmissible but milder, with the virus concentrating in the throat and not reaching the lungs. The original variant is less contagious but more dangerous and more lethal.

Pfizer’s vaccines use messenger RNA technology, in which a portion of the spike protein, responsible for fixing the virus in cells, is injected to stimulate antibody production. The bivalent immunizers will have gray-colored vials for easy identification.

Purchase

It will now be up to the Ministry of Health to purchase the bivalent vaccines. Currently, there is a contract for the acquisition of 100 million doses from Pfizer to be delivered starting this year. It provides for the addition of 50 million doses, including updated or pediatric immunizers, in case the ministry orders them.

Anvisa director Meiruze Souza Freitas explained that bivalent vaccines are already used in several countries and, although the original vaccines remain efficacious, bivalents are more effective against the latest sub-variants. Freitas emphasized the importance of vaccination because, according to her, it is not yet possible to know the severity of the BA4/BA5 variants.

Background

In August this year, Pfizer sent Anvisa the first request for analysis of the bivalent vaccine that protects against the Omicron BA.1 sub-variant. In late September, the manufacturer filed the second request for analysis against sub-variants BA.4, and BA.5.

The agency’s decision comes at a time of an increasing number of cases in the country linked to the circulation of a new Omicron sub-variant.