Immunisering

Immunisation, or vaccination, is the process of giving a vaccine to stimulate protective immunity against infectious diseases. Vaccines introduce components that resemble pathogens or their genetic instructions, enough to trigger an immune response without causing the disease. The body produces antibodies and memory cells, so future exposure to the real pathogen is more likely to be prevented or the disease is milder.

Vaccines vary in composition and delivery. Types include live attenuated, inactivated, subunit, toxoid, and newer platforms such as mRNA vaccines. Administration routes include intramuscular, subcutaneous, oral, and intranasal, depending on the vaccine. Immunisation schedules are set by health authorities and typically begin in infancy, with booster doses to sustain protection.

Widespread immunisation reduces disease incidence and mortality and can establish herd immunity, protecting those who cannot be vaccinated. Safety monitoring systems track adverse events after immunisation; most reactions are mild, while serious events are rare. Decisions about vaccination take into account medical contraindications and public health considerations.

Vaccination has a long history, contributing to the control and elimination of many diseases, such as smallpox and polio. Global immunisation remains an equity issue, with ongoing efforts to expand access and ensure high coverage, particularly in low-income regions.