4.1.8(vaccination)

Describe how vaccinations lead to immunity

• Vaccinations contain antigens - These antigens may be free or attached to dead or attenuated pathogen. They are harmless

• The antigens cause the body to produce B and T memory cells as a immune response against the particular pathogen without causing a disease

• The B and T memory cells then remain in the blood for years so when the actual pathogen enters the body, the immune response will be secondary and very fast

State 5 ways in which pathogenic material is used in vaccines

• Whole, live microorganisms - usually ones that are not harmful that can cause disease

• Attenuated version of the pathogen

• A dead pathogen

• A preparation of the antigens from a pathogen

• A toxoid, which is a harmless version of a toxin

State the 2 different types of vaccination

• Herd vaccination

• Ring vaccination

Describe how herd vaccination prevents the spread of disease

• In herd vaccination, almost all of the population is vaccinated(80-85%)

• This provides immunity to all or almost all of the population at risk

• Once enough people are immune, the disease can no longer spread through the population and herd immunity is achieved

Describe how ring vaccination prevents the spread of disease

• It is used when a new case of a disease is reported

• People who are around the site of the outbreak are vaccinated

• Therefore the pathogen will no longer be transmitted across the ring and will therefore not be able to infect the rest of the population

State 5 things that make a good vaccination program

• Cheap

• few to no side effects

• Easy to store

• Easy to transport

• Easy to administrate

Describe how epidemics can arise from previous epidemics

• Pathogens may undergo mutations which can change their antigens

• The memory cells produced by vaccination may not recognise the new antigens

• When this occurs, the pathogen can then be transmitted and spread across the population

Describe how epidemics can be controlled

• Threats from epidemics can be monitored so that new strains of pathogens can be identified

• This enables health authorities to prepare for an impending epidemic by stockpiling suitable vaccines and vaccinating people who are at particular risk from the disease

Describe what is meant by antigenic variation

• This is when pathogens have the ability to alter their antigens.

• For example, influenza virus. New vaccines are needed each year as a result

State the 4 types immunity

• Natural

• Artificial

• Active

• Passive

Describe what natural and artificial immunity is

• Natural: gained through infection or as a result of normal life processes

• Artificial: Gained as a result of a deliberate exposure to antibodies or antigens

Describe what is meant by passive and active immunity

• Passive: Short term immunity provided by antibodies that have not been produced by the person’s own immune system

• Active: Long term immunity where antibodies are produced through activation of immune response after being stimulated by an antigen

What is Natural active and natural passive immunity and where do they arise from

• Natural active:

  • Immunity is provided by antibodies that are made in the immune system as a result of an infection

  • A person suffers from a disease once and is then immune

• Natural passive:

  • Acquired from the mother via placenta or breast milk

  • Provides immunity to diseases which the mother is immune to

  • Used in the first year of the baby’s life when the immune system is developing

What is Artificial active and artificial passive immunity and where do they arise from

• Artificial active:

  • Antibodies made by immune system in response to a vaccination and not due to infection

  • A person is injected with weakened, dead or similar pathogen or with antigens which causes the immune system to become activated

• Artificial passive:

  • immunity that is provided by Antibodies given via intravenous drip

  • These antibodies are made by another individual

Compare passive and active immunity?

• Active immunity:

  • Requires exposure to antigen

  • It takes a while for a protection to develop

  • long term immunity and protection

  • Memory cells are produced

• Passive immunity:

  • No exposure to antige

  • Immunity and protection is immediate

  • Protection and immunity is short term

  • No memory cells are produced