Inactivated Vaccines

Dead vaccines contain inactivated (no longer divisible) pathogens or parts thereof. This means that there is no risk of active infection (vaccine disease).

Inactivated vaccines are used in active immunization (see also passive immunization). Either inactivated whole pathogens (particulate vaccines) or only important antigenic components (proteins, polysaccharides) extracted from natural pathogens or produced recombinantly by means of genetic engineering) are used as dead vaccines.

In most cases, the antigenic structures are isolated, purified and, if necessary, modified. For example, the particles of influenza viruses must be cleaved (split vaccines) to extract the antigenic proteins in the envelope (hemagglutinin and neuraminidase). The lipids in the viral envelope must be removed to improve tolerability.

A special form of inactivated vaccines are toxoid vaccines whose toxicity must be attenuated (tetanus toxin, diphtheria toxin).

Serious side effects after vaccination with inactivated vaccines are very rare. However, the vaccination protection wears off after a certain time, so that a booster becomes necessary.

The organism initially reacts to this type of vaccination with the help of B cells and T helper cells with antibodies of the IgM class of low affinity. After days, IgG antibodies with increasing affinity are produced. The T cells acquire an immunological memory (memory cells), so that they enable a booster reaction when the antigen is repeatedly administered. The build-up of measurable and resilient immunity (basic immunisation) takes at least 7-10 days.

Inactivated vaccines are used, for example, against tetanus, hepatitis A and B, cholera, tick-borne encephalitis (TBE), Japanese encephalitis,

rabies, polio (IPV ), pertussis (cellular vaccine), pneumococcal and meningococcal diseases.