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How Vaccines Work

How vaccines work

How vaccines work

How Vaccines Work


Through effective vaccination programmes we have seen a great reduction in disease burden, with vaccines saving up to 2-3 million lives every year.[1] It remains evermore important that we ensure the uptake of vaccination continues, to allow many more lives to be saved.

Vaccination is one of the most successful public health interventions.[1] It allows the immune system to develop protection against certain illnesses by exposing the body to antigens (a substance foreign to the human body that induces an immune response) which mimic (components of) a pathogen (a bacterium, virus, or other disease-causing microorganism), but does not cause severe disease.[2],[3],[4]

How the immune system protects us from disease [2],[3],[4]


How vaccines protects us from disease [2],[3],[4]



The immune system remembers the antigens/pathogen


The immune system produces memory cells which remember the antigens / pathogen. In the future these cells will recognise the real pathogen and prevent you from getting seriously ill.

As a result of exposure to both natural infection and vaccines, memory cells are created. Memory cells ensure that the immune system recognises the pathogen during a future (real) infection, and responds faster. In this way, the immune system is primed to fight off the infection before you get seriously ill. [2],[3],[4]

Vaccines. With the exception of safe water, no other modality, not even antibiotics, has had such a major effect on mortality reduction.[6]

Susan & Stanely Plotkin





[1] World Health Organization. Immunization. Available at: Accessed: September 2021.

[2] Understanding how vaccines work. Available at: Accessed: September 2021.

[3] Live Science. How Do Vaccines Work? Available at: Accessed: September 2021.

[4] Children's Hospital of Philadelphia. Making Vaccines: How Are Vaccines Made? Available at: Accessed: September 2021.

[5] Centers for Disease Control and Prevention. Possible Side Effects After Getting a COVID-19 Vaccine. Available at: Accessed: September 2021.

[6] Plotkin S L,Plotkin S A.A short history of vaccination. In: Plotkin S, Orenstein W, Offit PA. Vaccines. 5th edition. Page 1. Philadelphia: Saunders, 2008.