| COMPARISON OF ATTENTUATED (LIVE) AND INACTIVATED (KILLED) VACCINES | ||
| CHARACTERISTIC | ATTENUATED VACCINE | INACTIVATED VACCINE |
| Production | Selection for avirulent organisms: virulent pathogen is grown under adverse culture conditions or prolonged passage of a virulent human pathogen in different hosts |
Virulent pathogen is inactivated by chemicals or irradiation with g-rays. |
| Booster requirement | Generally requires only a single booster |
Requires multiple boosters |
| Relative stability | Less stable | More stable (advantageous for Third World countries where refrigeration is limited) |
| Type of immunity induced | Produces humoral and cell- mediated immunity |
Produces mainly humoral immunity |
| Reversion tendency | May revert to virulent form | Cannot revert to virulent form |