The Science Behind Vaccine Research and Testing

How Vaccines Are Made And Tested

The creation of a vaccine (cdc.gov) involves scientists and medical experts from around the world, and it usually requires 10 to 15 years of research before the vaccine is made available to the general public. The first step of this extensive process involves several years of laboratory research, in which scientists and researchers identify an antigen that can prevent a disease.

Once the test vaccine has been cleared for further investigation by the U.S. Food and Drug Administration, at least three more phases of thorough clinical trials are conducted on human volunteers to test vaccine efficacy, to determine appropriate dosage, and to monitor for adverse side effects, etc. These trials usually take several more years to complete. The last phase involves a test group of up to tens of thousands of human volunteers. Unsure if this is a large enough test group? Consider this -– medicines in the United States also go through incredible scrutiny, but their test subject sample sizes are three times smaller than vaccine test subject groups.

But that's not the end of it: Once approved, the FDA continues to closely monitor the vaccine (fda.gov). It tests everything from batches of the vaccine to the production process and the facilities for safety. The FDA also conducts ongoing monitoring of vaccine reactions. Numerous agencies also work together on a global level to track, collect and analyze data, to make sure these vaccines are, and remain, safe for the general population. For more information on vaccine coordination and monitoring, visit the CDC's page on Why It's Important to Monitor Vaccine Safety (cdc.gov) and the Immunization Safety Office (cdc.gov/).

Unlike other vaccines, which typically take 10 to 15 years of research, development and testing before being approved by the U.S. Food and Drug Administration (FDA), seasonal flu vaccines are developed on an annual basis. While the antigen changes in the flu vaccine every year, the manufacturing process remains the same and is founded on ongoing virus tracking around the world. Scientists can determine which flu virus is most likely to circulate during the next flu season, and once identified, can change the antigen but keep everything else in the vaccine the same. This process builds on time-proven techniques and allows the medical community to respond quickly to protect the public from changing flu viruses. For more information visit The Proof Behind Vaccine Safety

The exhaustive amount of scientific evidence confirming that vaccines are safe should ease anyone's concerns about how they're made and tested. The flu vaccine is no exception.

Vaccines build your body's immune system so that, in the future, it's able to fight against a specific disease. Today's arsenal of vaccines protect us against many types of diseases that we could still encounter in our lives. Many of these diseases can be crippling or even deadly if you come into contact with them and aren't vaccinated.

Vaccine Ingredients

Injecting something into your body can be concerning for some, especially when you're unsure of what's inside the needle. We're here to take the mystery out of a vaccine's ingredients.

A vaccine contains a part of a germ (bacteria or virus) that is called an antigen. The antigen has already been killed or disabled before it's used to make the vaccine, so it can't make you sick. Antigens are substances, often a protein, that stimulate the body to produce an immune response to protect itself against attacks from future actual disease exposure. In addition, vaccines contain other ingredients that make them safer and more effective, including preservatives, adjuvants, additives and residuals of the vaccine production process. Because specific ingredients are necessary to make a vaccine, even though they are eventually removed, trace amounts can still remain. These residuals can include small amounts of antibiotics and egg or yeast protein. The American Academy of Pediatrics also provides a good explanation about what's inside the vaccine needle. (aap.org)

If you're a parent concerned that your child may be exposed to too many antigens, there's no need to worry: Today's vaccines contain far less antigens than in the past (chop.edu), thanks to advances in biomedical science. Additionally, children's bodies are well equipped to handle many antigens at the same time. A healthy baby can accommodate multiple vaccinations because vaccines, and the antigens they contain are designed for babies' immune systems. In fact, babies can handle significantly more antigens than those that are found in vaccines.

A few years ago, much attention was placed on thimerosal, an organic form of mercury (also called ethylmercury) that prevents vaccines from being contaminated. This form of mercury is different from methylmercury, which can damage the nervous system. Although thimerosal has been shown to be safe, now all routine childhood vaccines are produced in thimerosal-free form. This includes the flu vaccine.