The flu, or influenza, vaccine contains a number of ingredients, including preservatives, material of the virus it is protecting against and other agents to assist in the efficacy of the shot. The Centers for Disease Control and Prevention (CDC) recommends the flu vaccine for nearly all adults, children and infants, in most cases. Each year the seasonal flu vaccine is adjusted to compensate for what health officials believe will be affecting patients. The base ingredients of the vaccine generally stay the same. In addition to the genetic material of the flu virus, the vaccines contain preservatives and enhancers.
Aluminum
The CDC indicates that aluminum gels or salts are added to the vaccine to help improve the response it entices in the body. This is called an adjuvant or enhancer that improves the work of the vaccine. The ending result of the adjuvant is a more potent, more rapid and more persistent immune response to the vaccine.
Antibiotics
Antibiotics are added to some flu vaccines. Such antibiotics include, but are not limited to, polymyxin B, gentamicin or gentamicin sulfate, according to the CDC. This is done to reduce the growth of bacteria in the solution while it is being produced or stored.
Egg Protein
The influenza vaccines contain some form of egg protein, the CDC says. The egg protein is taken from chicken eggs. Individuals who have an egg or egg product allergy may experience an allergic reaction to the vaccine. Alternatives to this form of injection are available.
Formaldehyde
Formaldehyde is used in toxoid vaccines. Toxoid vaccines refer to the types containing inactive or killed flu viruses. The nasal flu mist vaccine does not contain this solution as it contains a small dose of the live flu virus. Injectable flu vaccines, however, do contain killed viruses, and several are made with formaldehyde. The CDC explains that formaldehyde can kill unwanted viruses or bacteria that can contaminate the vaccine during production.
Monosodium Glutamate (MSG)
Monosodium glutamate (MSG) is used to stabilize some, but not all, of the flu vaccines. This prevents the vaccine from changing in heat, light, acid or humidity exposure.
Thimerosal
Some flu vaccines are distributed to health facilities in multi-dose vials. The mercury-based preservative, thimerosal, is included to prevent contamination and growth of harmful bacteria in the vaccine solution.
