TRADITONAL VACCINES

Inactivated vaccines
Inactivated vaccines (e.g., for hepatitis A, rabies, polio) still carry the full repertoire of immunogenic components of the original pathogen. Proper inactivation is mandatory to avoid viral reactivation and replication in the host.

➕ Pathogen inactivation by radiation, heat, or chemical reagents ensures a superior safety profile and advantages in terms of transport and storage.

➖ Require processing of large quantities of the pathogen. The inactivation process can affect the antigen immunogenicity. As the antibody titers reduces over time, several booster doses are needed.

Live-attenuated vaccines
Repeated subculturing in a foreign host belongs to the most common methods to obtain attenuation of live-attenuated vaccines (e.g., for variola virus, measles virus, rotavirus). With each passage, the virus becomes less virulent. The native viral antigen conformation is still preserved, mimicking the natural infection without causing disease.

➕ Usually produce long-lasting robust cellular and humoral immune responses with only one administration.

➖ Safety issues in immunosuppressed people may occur, weakened strains are difficult to obtain, development time is long, and refrigeration obligatory.