11.2.4
Vaccines
Vaccination
Vaccination
Vaccines help the immune system recognise and destroy pathogens.


Insertion of antigens
Insertion of antigens
- Vaccines insert the antigens for a specific disease into the individual.
- The antigens can be inserted by:
- Injection.
- Oral insertion (oral vaccinations may be broken down in the stomach).


Primary immune response
Primary immune response
- The presence of antigens in the body induces the primary immune response.
- The antigens are inserted as a dead or weakened pathogen so the vaccine does not give rise to a full-scale infection with symptoms.


Memory cells
Memory cells
- The primary immune response leads to the production of memory cells.


Immunity
Immunity
- Memory cells provide immunity.
- If the individual is infected by a living pathogen, the memory cells will be ready to induce a fast, strong secondary response.


Booster vaccinations
Booster vaccinations
- Booster vaccinations can be given over time to make sure the memory cells are still in the body.


Continuous trial
Continuous trial
- Some vaccinations are continuously being changed because the antigens are evolving at a very rapid rate.
- Pathogens evolve to avoid detection by the immune system. This causes a problem because it makes the vaccines useless.
- Pathogens with a high mutation rate (e.g. influenza and HIV) are the most difficult to vaccinate against.
Herd Immunity
Herd Immunity
Herd immunity is the concept that if enough people in a population have immunity against a disease, the entire population are less likely to be infected.


Spread of a pathogen
Spread of a pathogen
- Herd immunity works if a large proportion of the population is vaccinated against a disease.
- If most of the population are immune, the chance of someone without immunity coming into contact with the disease is reduced.


Population requirements
Population requirements
- Herd immunity is the basis of widescale vaccination programs.
- If the disease is highly contagious (e.g. measles), over 90% of the population must be vaccinated.
- If the disease is less contagious (e.g. polio), over 80% of the population must be vaccinated.


Benefit
Benefit
- Herd immunity offers protection for the most vulnerable people in a population (e.g. new born babies and the elderly).
- Herd immunity had a major impact on the eradication of smallpox. Herd immunity helped smallpox become eradicated.


Difficulties with vaccines
Difficulties with vaccines
- Some diseases are harder to vaccinate & eradicate than others.
- Vaccines for TB are not 100% effective. It's also difficult to deliver the vaccine to poor communities who need it most.
- Measles has not been eradicated due to poor vaccine uptake. This occurred following a fabricated link between the vaccine and autism.
- The malaria vaccine requires four shots and is not 100% effective. Not all patients return for all four shots.
- Cholera is easily treatable with fluid replacement and antibiotics. The vaccine itself produces some sickness, so is avoided.
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
Jump to other topics
1Cell Structure
1.1Cell Structure
1.1.1Studying Cells - Microscopes
1.1.2Introduction to Eukaryotic & Prokaryotic Cells
1.1.3Ultrastructure of Eukaryotic Cells
1.1.4Ultrastructure of Eukaryotic Cells 2
1.1.5Ultrastructure of Eukaryotic Cells 3
1.1.6Prokaryotic Cells
1.1.7Viruses
1.1.8End of Topic Test - Cell Structure
1.1.9Exam-Style Question - Microscopes
1.1.10A-A* (AO2/3) - Cell Structure
2Biological Molecules
2.1Testing for Biological Modules
2.2Carbohydrates & Lipids
2.3Proteins
3Enzymes
4Cell Membranes & Transport
4.1Biological Membranes
5The Mitotic Cell Cycle
6Nucleic Acids & Protein Synthesis
6.1Nucleic Acids
7Transport in Plants
8Transport in Mammals
8.1Circulatory System
8.2Transport of Oxygen & Carbon Dioxide
9Gas Exchange
9.1Gas Exchange System
10Infectious Diseases
10.1Infectious Diseases
10.2Antibiotics
11Immunity
12Energy & Respiration (A2 Only)
13Photosynthesis (A2 Only)
14Homeostasis (A2 Only)
14.1Homeostasis
14.2The Kidney
14.3Cell Signalling
14.4Blood Glucose Concentration
14.5Homeostasis in Plants
15Control & Coordination (A2 Only)
15.1Control & Coordination in Mammals
15.1.1Neurones
15.1.2Receptors
15.1.3Taste
15.1.4Reflexes
15.1.5Action Potentials
15.1.6Saltatory Conduction
15.1.7Synapses
15.1.8Cholinergic Synnapses
15.1.9Neuromuscular Junction
15.1.10Skeletal Muscle
15.1.11Sliding Filament Theory Contraction
15.1.12Sliding Filament Theory Contraction 2
15.1.13Menstruation
15.1.14Contraceptive Pill
15.2Control & Co-Ordination in Plants
16Inherited Change (A2 Only)
16.1Passage of Information to Offspring
16.2Genes & Phenotype
17Selection & Evolution (A2 Only)
17.2Natural & Artificial Selection
18Classification & Conservation (A2 Only)
18.1Biodiversity
18.2Classification
19Genetic Technology (A2 Only)
19.1Manipulating Genomes
19.2Genetic Technology Applied to Medicine
19.3Genetically Modified Organisms in Agriculture
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