The regular Flu Vaccine injection for 2021 contains 4 different virus strains which include: A/Victoria/2570/2019(H1N1)pdm09-like strain (A/Victoria/2570/2019, IVR-215), A/Cambodia/e0826360/2020 (H3N2) -like strain (A/Tasmania/503/2020,IVR-221), B/Washington/02/2019-like strain (B/Washington/02/2019, wild type), B/Phuket/3073/2013 -like strain (B/Phuket/3073/2013, wild type). For those over 65 years of age, there is an adjunct Flu Vaccine for 2021. This adjunct MR59 is belief to increase the immunity of the vaccine to help make it more effective against the flu virus that may come.