The National Health Surveillance Agency (Anvisa) approved today (26) the composition of the trivalent and quadrivalent flu vaccines that will be used in the country in 2023.
For next year, doses produced from chicken eggs should use the following strains: Influenza A/Sydney/5/2021 (H1N1) pdm09; Influenza A/Darwin/9/2021 (H3N2); and Influenza B/Austria/1359417/2021 (strain B/Victoria).
In non-egg vaccines, the virus strain A (H3N2) must be a virus similar to Influenza A/Darwin/9/2021 (H3N2), along with the other strains A (H1N1) and B.
Quadrivalent vaccines, which cover two types of Influenza B virus strains, must contain virus similar to Influenza B/Phuket/3073/2013 virus (B/Yamagata lineage), in addition to the three types of strains required for trivalent vaccines.
As soon as the composition of the doses is published by the agency, the pharmaceutical companies holding the registration must adjust their products for the manufacture of the input targeting the year 2023.
Each year, the World Health Organization (WHO) analyzes all the influenza subtypes circulating on the planet and defines those which occur with the greatest intensity in order to improve the effectiveness of the doses.
“In accordance with WHO determinations, each year Anvisa publishes the composition of the influenza vaccines that will be used the following year,” the agency said.
“Changing the composition of strains (types of viruses) of influenza vaccines is critical for vaccine effectiveness because viruses adapt and mutate,” he added.