Anvisa updates Covid vaccines to monitor variants in circulation

The rule replaces the rule published in March and maintains the recommendation to update immunizers to monitor the evolution of Sars-CoV-2. The text details which strains can be used in the formulation of vaccines and what evidence will be required to approve other compositions.

According to the rule, published in the Official Gazette of the Union this Thursday (9), immunizers must be monovalent, that is, formulated to stimulate the body's response against a single lineage of Sars-CoV-2. The composition must include the LP.8.1 strain or antigens derived from the JN.1 lineage, such as the XFG or NB.1.8.1 sublineages.

The standard also allows other compositions. To do this, manufacturers must prove that they induce a broad response of neutralizing antibodies, capable of blocking the virus from entering cells, or that they are effective against coronavirus variants in circulation at the time of the update.

Anvisa foresees a transition period for changing the formulation. Vaccines against Covid already registered and produced before the update, as well as doses that are already distributed in the country, can be used for up to nine months after the agency approves the updated version of that vaccine.

The deadline, however, may be reduced or interrupted if there is an express statement from Anvisa to the contrary.

To update a vaccine that does not meet the criteria defined by the standard, the manufacturer must submit a specific protocol to the agency. The request must include, at a minimum, information on production and quality of the new formulation and safety and efficacy data following WHO (World Health Organization) criteria.

As Sars-CoV-2 continues to evolve and give rise to new strains, the composition of vaccines needs to be updated periodically to keep up with the variants in circulation. The strategy is similar to that adopted with the flu vaccine and seeks to maintain protection against the most serious forms of the disease and deaths.

For the population, the change means that vaccines will have a composition closer to the strains of the virus in circulation. The update does not invalidate the doses already taken, which remain important in protecting against serious cases and deaths, but reinforces the need to follow booster recommendations.

Read Also: Prouni 2026: free registration for the 2nd semester ends this Friday