Inactivated whole-cell (killed antigen) vaccines

Inactivated vaccines are made from microorganisms (viruses, bacteria, other) that have been killed through physical or chemical processes. These killed organisms cannot cause disease.

Immune response

  • Inactivated whole-cell vaccines may not always induce an immune response and the response may not be long lived.
  • Several doses of inactivated whole-cell vaccines may be required to evoke a sufficient immune response.

Safety and stability

  • Inactivated whole-cell vaccines have no risk of inducing the disease they are given against, as they do not contain live components.
  • They are considered more stable than LAV vaccines.

The table lists the rare, more severe adverse reactions of these vaccines. Note the frequency of the adverse reactions to get an idea of how low or high the possibility of an adverse event is. Also read the Comments to understand additional context details on the adverse events.

Adverse reactions associated with inactivated whole-cell vaccines

  Vaccine Rare, more severe adverse reactions Frequency Comment
Pertussis (wP)30 Prolonged crying
and seizuresSeizureUncontrolled electrical activity in the brain, resulting in convulsion, physical signs, thought disturbances, or a combination of symptoms.
are uncommon 		less than 1% Minor adverse reactions such as localLocal (or localized)Restricted or limited to a specific body part or region. redness and swelling, fever and agitation are very common with wP vaccines (10 – 50%).
Hypotonic, hyporesponsive episodes (HHE)
are rare		 less than
0.1 – 0.2%		 Although mild with no lasting effect, these reactions have affected the acceptance of wP vaccineWhole cell pertussis (wP) vaccineA preparation of inactivated whole cell pertussis bacterium, used to immunize against pertussis. in some populations. All wP (or DTwPDTwP vaccineA combination of diphtheria and tetanus toxoids with whole cell pertussis vaccine together in one vaccine, used to immunize against diphtheria, tetanus, and pertussis.) vaccines contain aluminium salt as adjuvantAdjuvantA pharmacological agent (e.g., aluminum salt, oil-in-water emulsions) that modifies the effect of other agents, such as a drug or vaccine, while having few if any direct effects when given by itself. Adjuvants are often included in vaccines to enhance the recipient's immune response to a supplied antigen, while keeping the injected foreign material to a minimum. and in some cases thiomersalThiomersalThiomersal is a mercury-containing preservative that has been used in some vaccines and other products since the 1930's. While there is no evidence that the low concentrations of thimerosal in vaccines have caused any harm other than minor reactions like redness or swelling at the injection site, in July 1999 the US Public Health Service, the American Academy of Pediatrics, and vaccine manufacturers agreed that thimerosal should be reduced or eliminated from vaccines as a precautionary measure. Today, all routinely recommended childhood vaccines manufactured for the US market contain either no thimerosal or only trace amounts. as preservative.
Inactivated polio vaccine (IPV)29 None known – Many high-income countries have switched from OPV to IPV, as IPV is considered safer. IPV is more expensive than OPV and an injectable vaccine. Many lower- and middle-income countries use OPV.

Question

Which of the following statements is incorrect?

A. Inactivated whole-cell vaccines contain "killed" pathogens.
B. Inactivated whole-cell vaccines can be considered safer than live vaccines, particularly when used in vulnerable groups (immunocompromised persons).
C. Inactivated whole-cell vaccines can be considered more effective compared to live vaccines.
D. Inactivated whole-cell vaccines should not be seen as ineffective – the immunization schedule foresees repeated doses to ensure adequate immune responses in patients.

Answer

Answer C is incorrect.

  • Inactivated vaccines can be considered safer than live vaccines, which, however, comes with a reduced effectiveness of the vaccine. Inactivated vaccines should not be seen as ineffective – the immunization schedule foresees repeated doses to ensure adequate immune responses in patients.
  • Live vaccines on the other hand should not be seen as unsafe – their production is usually done with meticulous quality checks ensuring their safety. It is rather important to have well trained health staff screening patients for counter indications to the vaccines.
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