Getting the seasonal flu shot is the single best way to avoid getting the flu each year, according to the Centers for Disease Control and Prevention (CDC). In 2009, an additional vaccine was approved for the pandemic H1N1 or swine flu strain. In addition to virus, flu vaccines also contain a number of other ingredients.
Virus
Injectible vaccines supply inactivated influenza virus while intranasal vaccines supply live "attenuated" virus, which means that it is a weakened or ineffective form of the virus, according to the CDC. The seasonal flu vaccine is a trivalent vaccine; it supplies three different strains. Usually, those strains include 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 vaccine designed exclusively to combat the pandemic H1N1 strain. The seasonal flu and H1N1 vaccines are each available in both injection and intranasal forms.
Buffer Solution - Injectible Vaccine
According to the product literature supplied on the FDA website, H1N1/09 and seasonal flu 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. Due to the way that the virus is manufactured, these solutions may contain trace amounts of compounds such as sodium taurodeoxycholate (≤ 10 ppm), ovalbumin (≤ 0.000001 grams), neomycin sulfate (≤ 0.000000002 grams), polymyxin B (≤ 0.00000000003 grams), and beta-propiolactone (< .000000025 grams). Sodium taurodeoxycholate is a detergent found in bile salts. It is used to separate virus from parts of the hen eggs in which it is grown. Ovalbumin is the principle 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 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 prior to receiving the dose.
Buffer Solution - Intranasal Vaccine
Intranasal vaccine is also stabilized in phosphate buffered salt solution. Each 0.2 milliliter dose also contains monosodium glutamate (0.000188 grams), gelatin (0.002 grams), arginine (0.00242), sucrose (<0.014 grams) and gentamicin sulfate (<0.0000000015 grams.) Gelatin is used as a stabilizer. Arginine is an amino acid component of protein. Sucrose is also known as table sugar; it is used to separate the virus from other components of the hens' eggs. Gentamicin sulfate is an antibiotic used to prevent bacterial contamination.
Preservative
According to the FDA web site, all 2009 FDA-approved multidose influenza vaccines for seasonal and H1N1 contain thimerisol. Thimerisol is a mercury-containing compound used a preservative. Each 0.5 milliliter dose from a multi-dose formulation of influenza vaccine provides about 25 micrograms (0.000025 grams) of mercury as thimerisol.
