Which type of vaccine contains inactivated viruses or bacteria?

Inactivated vaccines are designed to contain viruses or bacteria that have been killed or inactivated so that they cannot cause disease. This type of vaccine usually invokes an immune response without the risk of causing the disease it aims to protect against. The inactivation process can utilize heat or chemicals, ensuring that the pathogen cannot replicate but still retains enough of its structure to stimulate an immune response effectively.

This distinguishes inactivated vaccines from live attenuated vaccines, which contain weakened forms of the live virus or bacteria, and thus can sometimes cause mild infections. Combination vaccines contain multiple antigens to protect against various diseases but can include both inactivated and live attenuated components. Protein subunit vaccines, on the other hand, are based on isolated components of the pathogen, such as proteins, rather than whole inactivated organisms.