What does immunisation mean?
Immunisation is the process of giving a vaccine to stimulate the immune system so that a person or animal can resist a particular infectious disease. It can refer to the administration of a single vaccine, such as an influenza injection, or to a wider programme providing protection against several diseases, as in childhood immunisation. The term is used in both British and American English, with “immunization” serving as the usual American spelling. Although vaccination and immunisation are often treated as interchangeable, immunisation more explicitly emphasizes the resulting immune protection, whereas vaccination highlights the use of a vaccine. Public-health immunisation programmes are central to preventing outbreaks and reducing deaths from diseases such as measles, polio, tetanus, and diphtheria. They may be delivered through clinics, schools, workplaces, mobile health units, and routine medical care. The practice is especially valuable because widespread immunisation can limit transmission and help protect vulnerable people who cannot receive certain vaccines themselves.
nounThe process of protecting a person or animal against an infectious disease by administering a vaccine or vaccines. It may also refer more broadly to the act of making someone immune to a disease.
- The administration of a vaccine or vaccines to produce immunity against an infectious disease.
- The broader process or act of making a person or animal immune to a disease.
"The programme provides free childhood immunisation against diseases such as measles and polio."
"Health workers arranged immunisation clinics in rural communities."
"Immunisation against influenza is especially important for people at higher risk of severe illness."
The standard plural refers to separate acts or programmes of immunisation.
"The clinic offered immunisations to eligible children throughout the summer."
Immunisation turns the body’s ancient defensive system into a form of preparation, enabling communities to build protection before an outbreak strikes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of immunisation
The word derives from the Latin immunis, meaning “free from” or “exempt,” and belongs to the same etymological family as immune and immunity. English developed immunise and immunisation alongside these older forms, using the Latin-derived stem immun- and the French-influenced suffix -isation. The terminology reflects the longstanding idea of making a person free or protected from the effects of a disease.
Related word forms
How immunisation is actually used
Immunisation is the standard British spelling; immunization is the standard American spelling. In public health, the term is often used collectively for vaccination programmes and their delivery.
Easily confused with immunisation
A vaccine is the biological preparation that stimulates immunity, whereas immunisation is the process of administering it.