Influvac Tetra 2022 Vaccine is given as an injection into a muscle by a doctor or nurse. It is usually given just before the cold season when the flu virus begins to increase. Normally, only one injection is required to protect you for a year. You should have the vaccination each year because different new strains of the flu virus emerge frequently and different vaccines are developed. It is especially important to have this vaccine if you are elderly or have chronic health problems such as diabetes, heart failure, kidney failure, or chronic obstructive pulmonary disease (COPD). It is also recommended for young children over 6 months of age.