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.
One reason the CDC is not favoring the quadrivalent vaccine over the trivalent vaccine is that they do not want people to miss getting a flu vaccine altogether because they're waiting for the quadrivalent option.âThere is only a limited supply of the quadrivalent vaccine this year,â Mossad said.reviously, the only flu shot available was a trivalent vaccine, meaning it protects against three strains of the disease. But now there's also a quadrivalent flu vaccine that protects against four flu viruses.