COVID-19 vaccines: Get the facts
Pathways to develop and produce a COVID-19 vaccine
Global health authorities and vaccine developers are currently partnering to support the technology needed to produce vaccines. Some approaches have been used before to create vaccines, but some are still quite new.
Live vaccines
Live vaccines use a weakened (attenuated) form of the germ that causes a disease. This kind of vaccine prompts an immune response without causing disease. The term attenuated means that the vaccine's ability to cause disease has been reduced.
Live vaccines are used to protect against measles, mumps, rubella, smallpox and chickenpox. As a result, the infrastructure is in place to develop these kinds of vaccines.
However, live virus vaccines often need extensive safety testing. Some live viruses can be transmitted to a person who isn't immunized. This is a concern for people who have weakened immune systems.
Inactivated vaccines
Inactivated vaccines use a killed (inactive) version of the germ that causes a disease. This kind of vaccine causes an immune response but not infection. Inactivated vaccines are used to prevent the flu, hepatitis A and rabies.
However, inactivated vaccines may not provide protection that's as strong as that produced by live vaccines. This type of vaccine often requires multiple doses, followed by booster doses, to provide long-term immunity. Producing these types of vaccines might require the handling of large amounts of the infectious virus.
Genetically engineered vaccines
This type of vaccine uses genetically engineered RNA or DNA that has instructions for making copies of the S protein. These copies prompt an immune response to the virus. With this approach, no infectious virus needs to be handled. While genetically engineered vaccines are in the works, none has been licensed for human use.