Conditions for Ideal Vaccines-

1. It should not be tumorigenic, toxic or pathogenic, i.e., it should be safe.

2. It should have very low levels of side effects in normal individuals.

3. It should not cause problems in individuals with impaired immune system.

4. It should not spread either within the vaccinated individual or to other individuals (live vaccines).

5. It should not contaminate the environment.

6. It should be effective in producing long lasting humoral and cellular immunities.

7. The technique of vaccination should be simple

.8. The vaccine should be cheap so that it is generally affordable. So far, such an ideal vaccine has not been developed.