Vaccines: The Basics
Questions about safety and effectiveness and what is in vaccines permeate the social, and various forms of media. The following information addresses several questions relating to ingredients used in manufacturing vaccines.
Active Immunity
Exposure to a disease organism triggers the immune system to produce antibodies to that disease. It can occur through infection with the actual disease (resulting in natural immunity), or introduction of a killed or weakened form of the disease organism through vaccination (vaccine-induced immunity). Either way, if an immune person comes into contact with that disease organism in the future, the immune system will recognize it and immediately produce the antibodies needed to fight it. Active immunity is long-lasting, and sometimes life-long. Passive Immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system.
Ingredients in vaccines: Antigens
are very small amounts of weak or dead germs that can cause diseases. They help the immune system learn how to fight off infections faster and more effectively. The flu virus is an example of an antigen. Adjuvants, which are in some vaccines, are substances that help the immune system respond more strongly to a vaccine. This increases one's immunity against the disease. Aluminum is an example of an adjuvant.
Ingredients keep vaccines safe and long lasting: Some ingredients help make sure a vaccine continues to work like it is supposed to and that it stays free of outside germs and bacteria. Preservatives, like thimerosal, protect the vaccine from outside bacteria or fungus. Today, preservatives are usually only used in vials (containers) of vaccines that have more than 1 dose. That is because every time an individual dose is taken from the vial, it is possible for harmful germs to get inside. Most vaccines are also available in single-dose vials and do not have preservatives in them. Stabilizers, like sugar or gelatin, help the active ingredients in vaccines continue to work while the vaccine is made, stored, and moved. Stabilizers keep the active ingredients in vaccines from changing because of something like a shift in temperature where the vaccine is being stored.
Ingredients are used during the production of vaccines: Some ingredients needed to produce the vaccine are no longer needed for the vaccine to work in a person. These ingredients are taken out after production so only tiny amounts are left in the final product. The very small amounts of these ingredients that remain in the final product are not harmful.
Examples of ingredients used in some vaccines include: Cell culture (growth) material, like eggs, to help grow the vaccine antigens. Inactivating (germ-killing) ingredients, like formaldehyde, to weaken or kill viruses, bacteria, or toxins in the vaccine. Antibiotics, like neomycin, to help keep outside germs and bacteria from growing in the vaccine.
Can vaccines with thimerosal cause mercury poisoning?
No. Thimerosal has a different form of mercury (ethylmercury) than the kind that causes mercury poisoning (methylmercury). It is safe to use ethylmercury in vaccines because it is less likely to build up in the body - and because it is used in very, very small amounts. Even so, most vaccines do not have any thimerosal in them. If you are concerned about thimerosal or mercury in vaccines, talk with your doctor.
Can people who are allergic to antibiotics get vaccinated?
Yes. However, if you have an allergy to antibiotics, it is a good idea to talk with your doctor about getting vaccinated. But in general, antibiotics that people are most likely to be allergic to - like penicillin - are not used in vaccines.
Can people with egg allergies get vaccinated?
Yes. People with egg allergies can get any licensed, recommended flu vaccine that is appropriate for their age. They no longer need to be watched for 30 minutes after getting the vaccine.
People who have severe egg allergies should be vaccinated in a medical setting and be supervised by a health care professional who can recognize and manage severe allergic conditions.
Is the formaldehyde used in some vaccines dangerous?
No. If formaldehyde is used to help produce a vaccine, only very small amounts are left in the final product. This amount is so small that it is not dangerous - in fact, there is actually more formaldehyde found naturally in our bodies than there is in vaccines made with formaldehyde.
Is the aluminum used in some vaccines dangerous?
No. Vaccines made with aluminum have only a very small amount of aluminum in them. For decades, vaccines that include aluminum have been tested for safety- these studies have shown that using aluminum in vaccines is safe.
Any vaccine can cause side effects. For the most part these are minor (for example, a sore arm or low-grade fever) and go away within a few days. There is a lengthy list of vaccines licensed in the United States and the side effects at CDC's Vaccine Information Statements (VISs), which in tum are derived from the Advisory Committee on Immunization Practices (ACIP) recommendations for each vaccine.
Note: most of this information comes directly from these two web sites. Information is in the public domain.