3.7 Flashcards
What are vaccines ?
Vaccines are a safe way of protecting against harmful pathogens prior to coming in contact with them.
How can vaccines help create immunity?
Antigens from a pathogen can be produced for vaccines allowing someone to safely gain an immune response to the pathogen, and thus creating memory cells, should they come in contact with it in the future.
How are vaccines prepared?
The pathogen antigen is often combined with an adjuvant in preparing vaccines. Adjuvants enhance the immune response.
What is the goal of mass vaccination programmes?
To achieve herd immunity
What is herd immunity?
is achieved when a large proportion of a population has been immunised
How are non-immune individuals protected in herd immunity?
As most people are immunised, there is far less chance that they will come in contact with an infected individual.
What factors does the herd immunity threshold depend on?
Density of population, the type of disease and the effectiveness of the vaccine
Give two difficulties that can arise in widespread vaccination
- a proportion of the population may refuse to receive the vaccination
- in the developing world, there may be difficulty in widespread vaccination due to poverty and difficulty accessing vaccinations.
How can some pathogens evade the immune system?
Over time, pathogens may alter their surface antigens, allowing them to evade the immune system a immune cells may not recognise them.
How does antigenic variation help the influenza virus?
Influenza virus has a very fast rate of antigenic variation. Therefore, each year, a new flu vaccine must be released to account for the continuing antigenic variation.
What is immunisation?
the process by which a person develops immunity to a disease-causing organisms
What is naturally acquired immunity?
if a person survives infection by a pathogen, subsequent exposure to the same antigen at a later date results in secondary response which prevents the disease from recurring. This person has acquired immunity as an immunological memory bu natural means.
What antigens can be used in vaccines?
- inactivated pathogen toxins
- dead pathogens
- part of pathogens
- weakened pathogens
What is active immunity?
refers to the protection gained as a result of the person’s body producing its own antibodies
What is an adjuvant?
a chemical substance that makes the vaccine more effective, therefore enchancing the immune rsponse.
