21st February 2024

Overview

It is important to be aware of the common types of vaccines along with specific situations where certain vaccines should not be given. 

Vaccines stimulate the immune system to recognise pathogens and produce antibodies against the pathogen. There are several types of vaccines used in current clinical practice:

• Live attenuated vaccine – Weakened ( attenuated) whole bacteria/virus by modifying the pathogen’s genetic material. This appears to elicit the best immune response but may result in uncontrolled pathogen replication in patients with weakened immune systems. Examples include:
  • Rotavirus 
  • Varicella/shingles
  • BCG
  • Yellow fever
  • ORAL typhoid
  • Live influenza
  • MMR
• Inactivated vaccine – Whole pathogens that have been killed or modified so that they are incapable of replicating. Examples include:
  • Inactivated polio
  • Hepatitis A
  • Rabies 
  • Japanese encephalitis
  • Inactivated influenzae 
• Recombinant protein vaccine – Protein subunits are created by inserting pathogenic DNA into yeast cells to produce polysaccharides/proteins that induce an immune response. Examples include:
  • Hepatitis B
  • Human papilloma virus
  • Meningococcal B
• Toxoid vaccine – Inactivated toxins are produced to induce immunity without causing clinical symptoms due to the inactivated nature of the toxoid. Examples include:
  • Diphtheria
  • Tetanus
  • Pertussis
• Conjugate vaccine – The pathogen’s polysaccharide antigen is attached to another material to induce a more robust immune response against the polysaccharide antigen. Examples include: 
  • Haemophilus influenzae B 
  • Meningococcal A,C,W,Y
  • Pneumococcal