Last updated on January 12, 2026
I’ve heard many different words used to describe vaccines. Is there a difference between vaccines, shots, doses, injections, and immunizations?
Yes, there are important differences among the words used to describe the process of protecting oneself against serious illness.
Immunization refers to the process of building defenses against disease and illness. An immunization can be an injection or a vaccine:
- An injection, or a shot, is a way of delivering a substance directly into the body through a needle or syringe. Injections may be used to give antibiotics, insulin, and other medications and substances, which typically have effects that last a few days or months. Injections may also be used to give vaccines, which typically provide long-term protection against specific diseases.
- Vaccines contain an inactive or weakened form of a virus, or instruct the body to make a part of the virus, to help the body build defenses against disease and illness. While injections are the most common method of giving vaccines, vaccines also come in other forms, including mists that people inhale and solutions people drink.
- Each injection comes in a package that contains the correct amount of a vaccine and other medications or substances, known as a dose.
What is a vitamin K injection? Is it necessary?
Vitamin K supports the body in controlling excessive bleeding when a person gets a cut or injury. Babies are born with low levels of vitamin K because they have low exposure during pregnancy and are not born with the ability to produce it on their own. A vitamin K injection is recommended to help alleviate vitamin K deficiency and protect against Vitamin K Deficiency Bleeding (VKDB) in the first few months of a baby’s life.
The vitamin K dose provides short-term protection, up to a few months, when a baby is most vulnerable to bleeding. An injection is more effective and lasting than oral doses. The injection has been a routine part of care for newborns for over 60 years.
What immunizations do babies receive at birth to protect against severe illness?
Per the American Academy of Pediatrics (AAP) Immunization Schedule, babies should receive the following immunizations to protect against severe illness at birth:
- The RSV immunization is an injection given at birth to provide short-term protection against severe disease during an RSV season. Babies should get the immunization dose at birth if they are born during or entering their first RSV season, and their birthing parent did not receive an RSV vaccine during pregnancy.
- The Hepatitis B vaccine is given as an injection and protects babies from long-term liver disease and cancer. Infants, babies, and children who contract Hep B are 80-85% more likely to experience chronic Hep B and its severe symptoms than adults who contract Hep B. That’s why the American Academy of Pediatrics (AAP) recommends that all infants receive their first dose of the Hep B vaccine at birth, followed by a second dose at one to two months old and a third dose at six to 18 months old.
Sources:
- World Health Organization. (2025, October). Vaccines and immunization: What is vaccination?
- American Academy of Pediatrics. (2025). Recommended Child and Adolescent Immunization Schedule for Ages 18 Years or Younger.
- American Academy of Pediatrics. (2022, February). Vitamin K and the Newborn Infant.
