According to Dispatch No. 1451/2022, signed by the Assistant Secretary of State and Health, António Lacerda Sales, the decision is based on the fact that the flu vaccine "should be administered annually" and that "flu viruses can present variations that require annual changes in the composition of the vaccine".

In the context of influenza, the dispatch highlights that "people aged 65 or over are the most vulnerable to complications". These are joined by other priority target groups, defined in annual regulations of the Directorate General of Health.

The Government also recalls that "the flu is a communicable disease that can develop into complications and that can be prevented or mitigated through vaccination", assigning to the Ministry of Health's Shared Services "the procedures for acquiring the respective vaccines".

The free vaccine is valid from the date of signing of the order, 27 January.