What is an inactivated vaccine?

An inactivated vaccine involves the use of complete viral or bacterial particles, but chemically treated (for example with formalin or chelating agents, such as ethylene oxide) or physically (with irradiation or heat), so that they lose any capacity for replication or to cause illness.

Compared to attenuated vaccines, they have the main advantages, stability and safety, but they usually induce a lower immune response and to ensure immunization more doses of vaccine should be given.

This type of immunization includes Salk's anti-rabies and anti-polyp vaccines.