The flu, also known as influenza, is a contagious illness that primarily targets the respiratory system. It is caused by influenza viruses.The symptoms may be mild to severe and even cause death. Individuals at risk for more severe symptoms include those that are immune compromised, the elderly, pregnant women, young children and persons with chronic diseases, such as asthma, heart, kidney, lung or liver disease. The U.S. Centers for Disease Control and Prevention states that the best way to prevent the flu is to get yearly vaccinations. Each season's flu vaccine has somewhat different components.
Flu Viruses
Flu vaccines are available as injectables or nasal sprays. The injectable vaccines contain viruses that have been killed and the nasal spray contains live, but weakened viruses. Manufacturers of flu vaccines grow the flu viruses in chicken embryos and then inactivate and purify them for use.
Active Components
Each year a new flu vaccine is produced that will protect against the three most likely circulating influenza viral strains. The trivalent vaccines are selected based upon research collected from more than 130 influenza centers around the world. The World Health Organization and the U.S. Food and Drug Administration make their recommendations each year for that season's vaccine requirement.
Preservatives
Injectable vaccines may contain the preservative, thimerosal in multi-dose vials, but not single dose vials. Thimerosal is an organic compound that contains mercury. It is metabolized to ethylmercury, not the neurotoxin, methylmercury. The CDC states that thimerosal does not cause serious adverse effects in the concentrations used in vaccines; however, as a precautionary measure manufacturers of vaccines have agreed to reduce or eliminate thimerosal in vaccines. The nasal spray flu vaccine, FluMist, does not contain preservatives.
Antibiotics
Antibiotics are used in the production of flu vaccines and small amounts may be present in the final product. The antibiotics that are used to prevent bacterial growth during the manufacturing process of flu vaccines are neomycin, kanamycin and gentamicin.
Other Inactive Components
Flu vaccines contain amino acids, sugars, salts and proteins to stabilize the product. These substances may include, monosodium glutamate, hydrolyzed porcine gelatin, arginine, sucrose, dibasic potassium phosphate, monobasic potassium phosphate, sodium chloride, potassium chloride and calcium chloride.
References
- U.S. Centers for Disease Control and Prevention: Seasonal Influenza
- PubMed: Seasonal Inactivated Influenza Virus Vaccines
- Health Industries Distributors Association: National Influenza Vaccine Summit
- U.S. Food and Drug Administration: Vaccines
- U.S. Centers for Disease Control and Prevention: Thimerosal
