As you can see from the chart, live attenuated and killed whole organism vaccines are some of the oldest types of vaccines.
Characteristics of live attenuated vaccines include:
- The whole organism is attenuated or weakened by treatment with chemicals or serial passages in tissue culture under unfavorable growth conditions. This creates mutations whereby the organism loses its pathogenicity but can still multiply in the vaccine recipient.
- The chief advantage of this type of vaccine is that it closely mimics a real infection, inducing a very strong and lasting response.
- A disadvantage to this type of vaccine is that there is a rare possibility that the weakened organism could mutate and could regain pathogenicity.
- The vaccine needs to be kept cool and transportation and storage could be a problem.
Characteristics of killed whole organism include:
- Chemical or physical agents kill the microbe and thus prevent any possibility of it regaining pathogenicity.
- Killing can alter the immunogenicity, thus causing a slower or weaker immune response.
- T cell and mucosal immunity are not as effective as in attenuated whole organism vaccines.
- These types of vaccines often require multiple boosters.
