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Celebrate Vaccines: key words in vaccine immunology

On Thursday 4 June 2020, the UK hosted Gavi, The Vaccine Alliance’s third donor pledging conference. Bringing together global leaders, the summit aimed to mobilise at least $7.4 billion towards the next phase in Gavi’s strategic plan (2021-25). Gavi received $8.8 billion in contributions which surpasses that target and will protect the next generation through vaccination, reduce disease inequality and create a healthier, safer and more prosperous world.

We support Gavi’s #VaccinesWork movement through our own advocacy project Celebrate Vaccines. Our initiative champions the role of vaccination and vaccine research in protecting us all against preventable disease.

An important goal of Celebrate Vaccines is to strengthen public knowledge and understanding of vaccination. Here, we explain some key words in vaccine immunology and the interesting history behind them.

Immune system


In medicine, immunity is your body's ability to resist infection caused by a pathogen such as a virus or bacterium.

While this medical sense of 'protection from disease' appears around 1880, the word itself comes from the much older and broader concept of immunity as the legal exemption from service or public duties e.g. not being required to pay taxes. In the classical language, Latin, immunitas means exempt from or not paying a share.1, 2

Our terms for the immune system and immunology have been adapted from the word immunity. 

Cowpox was used to prevent smallpoxVaccines & vaccination

A vaccine is a type of medicine that trains your body’s immune system to fight a specific pathogen. Vaccination is the process of introducing a vaccine into the body.

The word 'vaccination' was coined by English doctor, Edward Jenner, in the 1790s when he scientifically investigated the idea that exposing humans to cowpox, a mild disease found in cows, could protect against smallpox, a more serious disease affecting humans.

Dr. Jenner named this treatment 'vaccination' from the Latin word vacca meaning cow.

What's the difference between vaccination and immunisation?

While vaccination is the process of receiving a vaccine, immunisation is what happens in your body afterwards: your immune system learns to fight the pathogen so that it can identify and successfully resist infection in the future. This level of protection is called immunity and prevents you from getting sick.


Vaccination protects us against specific pathogens: disease-causing biological agents like viruses, bacteria, fungi, and parasites.

The word ‘pathogen’ comes from the French word pathogénique, which itself comes from the older Greek words pathos which means disease or suffering and gene which means 'born of'.3

From this meaning, we also have the word pathos denoting a technique used in artistic expression (books, theatre, etc.) to provoke an emotional response in the audience.4

Zika virus


A virus is a tiny piece of organic material that causes disease and can only survive by replicating within the cells of living hosts.

Although viruses were not discovered until the late 1800s, the word virus is much older and is identical to the Latin word it comes from meaning poisonous substance. In the 18th and early 19th centuries, the meaning of virus appears to denote anything that caused infectious disease.5, 6

Emerging from this physical idea of a virus is our poetic use of the term meaning something or someone that spreads a negative influence or effect. More recently, the word has crossed over into computer science to denote a self-replicating code designed to damage a system or network.

Rod shaped bacteria
Rod-shaped bacteria, known as bacilli


Bacteria are single-celled microbes (very small and simple microorganisms) that are all around us and inside our bodies. Bacteria is the plural form of bacterium.

While many bacteria are essential for our survival and good health, some cause diseases like cholera and bubonic plague.

Dutch scientist Antoni van Leeuwenhoek is credited with the discovery of bacteria in the 1670s. Leeuvenhoek called the small, strange creatures he observed ‘animacules’ or little animal in Latin.7, 8 

The modern name came much later in 1830, from German scientist Christian Gottfried Ehrenberg. Although bacteria are now classified according to their basic shapes, Ehrenberg chose the name based on his discovery of rod-shaped bacteria (bacilli) from the Greek word baktēria meaning stick or rod.9

Other types of bacteria include spherical (cocci), spiral (spirilla), comma (vibrios) and corkscrew (spirochaetes).

Antibody & Antigen

Antibodies are Y-shaped proteins made by our immune system to protect us against pathogens that have entered the body. Antibodies react with a specific part of the pathogen called antigens. Antibodies are also known as immunoglobulins.

Antibody is a direct translation from German (Antikörper) and literally means 'against-body'. German scientist Paul Ehrlich is credited with the term, which appears in his 1891 article "Experimental Studies on Immunity".10

Antigens were discovered later and their name reflects the antigen-antibody relationship: antigens on the pathogen generate the production of antibodies by our immune system. Antibodies are unique and bind to only a specific antigen. The image below illustrates the nature of this relationship, as each antibody (blue and green on the right) perfectly matches the specific antigen on the cell (blue and green shapes on the cell surface).

antibody antigen


We hope you enjoyed learning about these important words and where they came from.

For more information, educational activities and resources about vaccines, and to read our new report reviewing the UK's outstanding contribution to vaccine research, head over to our Celebrate Vaccines website.

Thank you for reading!


BSI Guide to Childhood Vaccination
Merriam Webster
Online Etymology Dictionary
Oxford English Dictionaries
Oxford Classical Dictionary
Royal Society Publishing
Vaccine Knowledge Project
World Health Organisation

Porter JR. Antony van Leeuwenhoek: tercentenary of his discovery of bacteria. Bacteriol Rev. 1976;40(2):260‐269.​

LINDENMANN, J. (1984), SENIOR OVERVIEWS. Scandinavian Journal of Immunology, 19: 281-285. doi:

Leewenhoeck A. (1677) Observation, communicated to the publisher by Mr. Antony van Leewenhoeck, in a Dutch letter of the 9 Octob. 1676 here English'd: concerning little animals by him observed in rain-well-sea and snow water; as also in water wherein pepper had lain infused. Phil. Trans. 12, 821–831. ​doi: