Influenza vaccine injection. Injection into a patient's arm of the 2018/2019 seasonal influenza (flu) vaccine for the northern hemisphere season. This is a quadrivalent inactivated vaccine designed for intramuscular and subcutaneous injection. Inactivated influenza vaccines contain dead influenza viruses. When injected, these stimulate the body's immune system to produce antibodies that protect against future infection by live viruses. Influenza vaccination is recommended for the elderly, the very young, and anyone suffering from respiratory or circulatory disease. It is provided annually because of the need to protect against new strains. This is a vaccine from the Sanofi Pasteur Europe company.