Vaccine is a biological preparation that provides active acquired immunity to a particular infectious disease.
It takes years for laboratory researchers funded by government, academic foundations or industry to find a natural or synthetic antigen that will help the immune system fight off a specific pathogen. Once that antigen is found, it’s tested in cells and animals to make sure it elicits the right response (Phase II testing). If the results are encouraging, vaccine makers can then test it in humans, in clinical trials with thousands of volunteers (Phase III). The Centers for Disease Control and Prevention and the Food and Drug Administration also continue to monitor and inspect vaccine manufacturers and facilities, and collect information about any side effects from vaccinated people via the Vaccine Adverse Event Reporting System.
Once a vaccine is made, it’s administered in the form of an injection, nasal spray or drops. A single dose of a vaccine usually has only a small amount of the active ingredient, known as an immunogen, or antigen. It’s diluted with other ingredients to help it work well, prevent contamination and ensure safety, such as stabilizers like sugar or gelatin and preservatives, such as the FDA-approved antibiotic thimerosal.
Different vaccines work differently, but most provide protection against a disease by stimulating the body to produce antibodies and cell-mediated immunity. If your immunity is strong enough, it can last a lifetime and may protect you from getting the disease even if someone around you gets sick with the same microbe. Vaccines are among humanity’s greatest achievements, and they can reduce the spread of some diseases to near-eradication levels.
About the Author
