TABLE 1.

Virus vaccine strategies

Vaccine strategyAdvantage(s)Disadvantage(s)Virus vaccine(s)
Inactivated (killed)Stable formulations, safety in absence of viral replication, humoral immune responseAbsence of strong cell-mediated immune response, multiple doses may be required, vaccine virus propagated to high titers (safety issue), potential adverse reactions (incomplete inactivation of infectious virus nucleic acids)Influenza A and B viruses, poliovirus, hepatitis A virus, rabies virus
Live attenuatedInduce strong humoral and cell-mediated immune responseLow-level virus shedding may pose risk to immunocompromised persons, high mutation rate of RNA viruses (potential for reversion to wild type)Measles virus, yellow fever virus, varicella-zoster virus, influenza A and B viruses
Subunit/expressed proteinIncreased safety in absence of virus, large volumes can be produced rapidlyMultiple doses may be required, antigenic proteins and epitopes must be knownHepatitis B virus
VectoredViral protein expressed in natural form
DNA vaccinesIncreased safety in absence of virus, relatively easy to designLow immunogenicity in humans