According to the Centers for Disease Control and Prevention (CDC), influenza causes more than 200,000 hospitalizations and 35,000 deaths each year, especially in elderly people. In many cases, influenza can be avoided through seasonal immunization.
Virus
According to the CDC, the flu shot contains inactivated or "killed" influenza virus. Intranasal vaccines such as FluMist supply live "attenuated" virus, a weakened or ineffective form of the virus. The seasonal flu vaccine is a "trivalent" vaccine that combats three different strains of the influenza virus. Although the individual strains vary each year, the types of strains selected for the vaccine usually consist of an influenza A strain, an H1N1 strain (not the pandemic 2009 strain) and an influenza B strain. In 2009, the FDA also approved a "monovalent," or single strain, vaccine designed exclusively to combat the pandemic H1N1 strain.
Buffer Solution - Flu Shot
According to the FDA and the manufacturer's product literature, H1N1/09 and seasonal flu injection vaccines are suspended in sterile phosphate-buffered sodium chloride (saline) solutions with a pH and concentration similar to the fluid that surrounds the cells in the human body. The vaccine may contain traces of compounds used in manufacturing. Examples include sodium taurodeoxycholate (≤ 10 ppm), ovalbumin (≤ 0.000001 grams), neomycin sulfate (≤ 0.000000002g), polymyxin B (≤ 0.00000000003g) and beta-propiolactone (< .000000025g).
Sodium taurodeoxycholate is a detergent found in bile salts. It's used to separate virus from parts of the hen eggs in which it's grown. Ovalbumin is the principal protein found in egg whites. Neomycin sulfate and polymyxin B are topical antibiotic medications. They are used to prevent bacterial contamination. Beta-propioloactone is used to inactivate the virus. The components of flu vaccine may vary from season to season and are always listed on the package insert that accompanies the dose. Allergic reactions are extremely rare. However, people with known allergies to any of the compounds in the vaccine should share this history with their physician before receiving the flu shot.
Buffer Solution - FluMist
FluMist is the intranasal vaccine. Like the flu shot, it's also stabilized in phosphate buffered salt solution. Each 0.2ml dose also contains monosodium glutamate (0.000188g), gelatin (0.002g), arginine (0.00242g), sucrose (<0.014g) and gentamicin sulfate (<0.0000000015g). Gelatin from pigs is used as a stabilizer. Arginine is an amino acid component of protein. Sucrose is also known as common table sugar; it's used to separate the virus from other components of the hens eggs. Gentamicin sulfate is an antibiotic used to prevent bacterial contamination. Although serious allergic reactions are rare, people with a history of allergy to any of the components of FluMist should discuss this with their health care provider before receiving the vaccine.
Preservatives
According to the FDA website, all 2009 FDA-approved multidose influenza vaccines for seasonal and H1N1 contain thimerisol. Thimerisol is a mercury-containing compound used as a preservative. Each 0.5ml dose from a multi-dose formulation of influenza vaccine provides about 25mcg (0.000025g) of mercury as thimerisol. Single-dose formulations of influenze vaccine don't usually contain thimerisol. The manufacturer's product insert always confirms the presence and quantity of mercury for a specific product.
