Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
vaccine
References & Edit History Related Topics
Images, Videos & Interactives
Lives saved by childhood vaccinations, 1974–2024 Vaccines by the numbers Smallpox vaccination Vaccine timeline Historical mass vaccination programs in the United States
Gloved hands draw liquid from a vial into a syringe, overlaid on a digitally colored microscopic image of a virus with round particles in clusters.
How did the polio vaccine change the world?
Human papillomavirus vaccine
Find out from Dr. Tina Tan of Northwestern University why adult vaccination against various types of diseases is important
Childhood vaccination
For Students
default image
vaccine summary
Quizzes
Artificial lung ventilation monitor in the intensive care unit. Nurse with medical equipment. Ventilation of the lungs with oxygen. COVID-19 and coronavirus identification. Pandemic.
Is There a Doctor in the House? Firsts in Medicine Quiz
Related Questions
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

External Websites
Britannica Websites
Articles from Britannica Encyclopedias for elementary and high school students.
Lives saved by childhood vaccinations, 1974–2024
Lives saved by childhood vaccinations, 1974–2024 Vaccines and the estimates of lives saved over the period 1974–2024.

vaccine

medicine
Written by
Emily K. Brunson
Contributor to SAGE Publications's Encyclopedia of Epidemiology (2008) whose work for that encyclopedia formed the basis of her contributions to Britannica.
Emily K. Brunson
Fact-checked by
Britannica Editors
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree....
Britannica Editors
Last updated
•History

vaccine, suspension of weakened, killed, or fragmented microorganisms or toxins or other biological preparation, such as those consisting of antibodies, lymphocytes, or messenger RNA (mRNA), that is administered primarily to prevent disease. Explore further: Vaccine mandates A vaccine can confer active immunity against a specific harmful agent by stimulating the immune system to attack the agent. Once stimulated by a vaccine, the antibody-producing cells, called B cells (or B lymphocytes), remain sensitized and ready to...

Discover the world with Britannica

Subscribe to Continue Reading

Free Trial | No Ads | Exclusive Content

Unsubscribe Anytime!

Explore Subscriptions
DNA
Right
Mobile