Please consult with your medical professional about the applicability of this information to your own situation. The content below includes links to external sites, which will open in a new browser window.

What are vaccines?

Vaccines are immunizations that generally come in the form of shots, and help our bodies to defend against a number of infectious diseases. Vaccines typically contain a killed or much weakened virus or protein that stimulates our body to produce antibodies against a specific disease.

How many vaccines are there?

Currently, there are 27 licensed vaccines in the U.S. to help prevent diseases like tetanus, polio, influenza, measles, mumps, hepatitis and HPV/cervical cancer.

Can a vaccine cause the disease it is supposed to prevent?

Most of our current vaccines are inactivated (killed), so that they cannot cause disease. A few vaccines use weakened or attenuated viruses, so they could theoretically cause disease, but generally do not.

What kinds of vaccines need to be studied?

There are several vaccines in development for treating diseases like bird flu, anthrax, tuberculosis and malaria. The hope is to find a bird flu vaccine that doesn’t depend on chicken embryos for its manufacturing, so that hundreds of millions of doses could be quickly produced in the event of a global outbreak of bird flu. We call our volunteers “everyday heroes” because they help to come up with solutions to some of the world’s biggest problems, such as the threat of pandemic bird flu.

For more information on vaccines:

Mayo Clinic: Top 5 Myths about Vaccines
WebMD: Immunizations
About the Flu
Vaccinations