Live vaccines use a weakened (attenuated) form of the germ that causes a disease. Because the germ is alive, but weakened, these vaccines create a strong and long-lasting immune response, often requiring fewer doses than other vaccine types. Several examples of live vaccines include:
Examples of Live Attenuated Vaccines:
- Measles, Mumps, and Rubella (MMR) vaccine: This combined vaccine protects against three viral diseases. MedlinePlus Medical Encyclopedia and CDC cite this as a common example of a live attenuated vaccine.
- Varicella (Chickenpox) vaccine: This vaccine protects against the chickenpox virus. Verywell Health, MedlinePlus Medical Encyclopedia, and CDC list this as a live vaccine.
- Rotavirus vaccine: This vaccine protects against rotavirus, a common cause of diarrhea in infants and young children.
- Smallpox vaccine: Historically used to eradicate smallpox, this vaccine used a live, but weakened, form of the virus. Verywell Health mentions this as an example.
- Yellow fever vaccine: This vaccine protects against yellow fever, a serious viral illness spread by mosquitoes. CDC references this as a live-virus vaccine.
- Oral polio vaccine (OPV): While largely replaced by the inactivated polio vaccine (IPV) in many countries, OPV is a live attenuated vaccine.
The CDC https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html and HHS https://www.hhs.gov/immunization/basics/types/index.html confirm that most live vaccines used are "live attenuated," meaning the microbe is alive but weakened. The FDA https://www.fda.gov/vaccines-blood-biologics/vaccines/vaccines-licensed-use-united-states also lists several live vaccines licensed for use in the United States, including ERVEBO (Ebola Zaire Vaccine, Live).
The National Cancer Institute https://www.cancer.gov/publications/dictionaries/cancer-terms/def/live-virus-vaccine explains that live virus vaccines help the body's immune system recognize and fight infections.
