An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments and also achieves boiling-point elevation (anti-boil) to allow higher coolant temperature.
The strains of virus the trivalent vaccine protects against two A viruses (an H1N1 and an H3N2) and an influenza B virus. The quadrivalent vaccine adds another B virus to the vaccine which helps expand the level of protection to the recipient.
Trivalent vaccines are available in: 1  Standard-dose trivalent shots (IIV3), approved for use in people six months and older. (Most flu shots are given with a needle. 2  High dose trivalent shot approved for people 65 years or older. 3  Recombinant trivalent shot that is egg-free, approved for people 18 years or older.