Table 1.

Advantages and disadvantages of attenuated and killed vaccines.

characteristic	attenuated vaccine	killed vaccine
thermostability	usually low	usually high
reactogenicity	usually low	frequently high
immunogenicity	usually long-lasting	often short duration
mucosal immunity	often strong	variable
safety	reversion to virulence may occur may cause serious infections in immunocompromised	safety high
indirect herd protection	may infect and protect non-vaccinated	can protect non-vaccinated by interrupting transmission