vaccinations and vaccines Flashcards
What vaccines are
Contains antigen / proteins / dead / weakened microorganism / pathogen / virus / bacteria; Stimulates production of antibodies / plasma cells / memory cells;
How they work
A vaccine stimulates the primary immune response, and produces memory cells against a specific antigen. It assumes that if there is a second infection, then the same antigen will be present on the pathogen.
What is meant by herd immunity
Herd immunity arises when a sufficiently large proportion of the population has been vaccinated (and are therefore immune) which makes it difficult for a pathogen to spread within that population
Those who are not immunised are protected and unlikely to contract it as the levels of the disease are so low
What passive and active immunity are and the differences between them
Immunity is made up of both innate and adaptive arms. Innate immunity, also known as natural or genetic immunity, is something an organism is born with, encoded in their genes and protects them throughout their life. Innate immunity consists of:
External defenses: Known as the first line of defense, external defenses work to protect an organism from pathogen exposure and include things like the skin, tears and stomach acid.
Internal defenses: Known as the second line of defense, internal defenses address a pathogen once it has entered the body and include things like inflammation and fevers and the chemical and cellular components that make up the innate immune system.
Why it is easier to develop vaccines for some diseases and not others
- because the influenza and common cold virus have lots of mutations and regularly change its surface antigen this is called antigenic variability therefore there is a need for revaccination as there might not be an effective vaccine
