Vaccine Say: vak-seen A vaccine is another word for what most kids call a shot. Even though getting vaccines isn't fun, they are very important because they help protect you against diseases. Back to Articles Related Articles Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.