Inactivated vaccines

• Whole vaccines

• Subunit vaccines

  • Protein-based

  • Polysaccharide-based

• Whole inactivated or dead pathogens (using chemicals or heat) that are unable to replicate

• Surface epitopes remain unchanged, since they are important for triggering an adequate immune response.

• Cause a weaker immune response, but are considered to be safer than live vaccines

• Polio (Salk; inactivated vaccine)

• Hepatitis A

• Rabies

• Typhoid (Vi polysaccharide; IM)

• Influenza

• Pertussis (cellular vaccine)

• Cholera

• Japanese encephalitis

• Tick-borne encephalitis

• Inactive antigenic subunits of pathogens that provoke the most effective immune response

• Weaker immune response and more expensive

• But lower risk of adverse reactions

• Subunit

  • Hepatitis B (using the HBsAg)

  • Influenza

  • Pertussis (acellular vaccine)

  • HPV (specifically types 6, 11, 16, and 18)

  • Anthrax

• Toxoids are bacterial toxins in which the toxicity has been inactivated while immunogenicity is maintained through intact receptor binding sites.

• Immune system reacts to exposure with production of antibodies against bacterial toxins → protective immunization

• Toxoid vaccine

  • Diphtheria (C. diphtheria)

  • Tetanus (Clostridium tetani)

• Mostly humoral immune response

• Number of circulating antibodies decreases over time

Less affected by circulating antibodies than live vaccines

• Bacterial cell wall polysaccharide

• Conjugate polysaccharide vaccine is linked to a protein

• Hib (conjugate vaccine)

• Pneumococcal vaccine

  • PCV13 (conjugate vaccine)

  • PPSV23 (unconjugated vaccine)

• Meningococcal vaccine (conjugate vaccine; various strains of Neisseria meningitidis)

• Salmonella typhi

• Polysaccharides induce a relative T cell-independent B-cell response and therefore achieve sufficient immunization only in adults and older children.

• In conjugate vaccines, the carrier protein activates T-cells, which stimulate a more rapid and long-lasting immune response, especially in infants and toddlers.

• Usually injected into the deltoid muscle (alternatively, e.g., in infants, injected into the vastus lateralis muscle)

• First dose does not provide protective immunity

• Multiple doses required

• Periodic “boosts” necessary to ensure sufficiently high antibody titers

• Inactivated vaccines may generally be combined with other vaccines without any time interval in between