1. Types of immunity and vaccination
Starting activity:
What is immunity
How do we become immune?

2. Learning Objectives
Learners should be able to demonstrate and apply their knowledge and understanding of:
the differences between active and passive immunity, and between natural and artificial immunity
autoimmune diseases
the principles of vaccination and the role of vaccination programmes in the prevention of epidemics
possible sources of medicines
the benefits and risks of using antibiotics to manage bacterial infection.

3. Types of immunity
Immunity = the means by which the body protects itself from infection
Immunisation = The process of artificially inducing immunity.
Immunity
Natural
Artificial
Active
Organisms own immune system is stimulated by contact with a disease
Passive
Antibodies are passed to an individual eg in Colostrum/breast milk or via the placenta
Organisms own immune system is stimulated
by a vaccine
Antibodies obtained chemically and administered often by a jab

4. Autoimmune diseases
The immune system stops recognising some cells as ‘self’ to will attack them causing inflammation and destruction of healthy tissues
Three of the most common
Type 1 diabetes damages the β cells in the pancreas
Rheumatoid arthritis attacks joints causing scarring and swelling
Lupus which can damage many organs such as kidneys and liver and skin often causing a persistent facial rash
There are no cures for these diseases but can be managed with other medications such as insulin injections or immunosuppresants

5. Artificial Active Immunity Vaccines
To make the pathogen safe for a vaccine there are a few options
Dead or Inactive pathogens
Whooping cough
Attenuated/weakened pathogens which are live
Rubella, Polio
Antigens from the pathogen
Influenza
These can be genetically engineered e.g. hepatitis
Modified toxins from the pathogen
Diptheria

6. Vaccination programmes
Approximate age
Vaccination
2 months
DTP, Tetanus and Pertussis (whooping cough), Polio, Meningitis type C
4 months
DTP, Polio (both 2nd doses)
6 months
DTP, Polio (3rd doses)
15-18 months
MMR combined vaccine
4-5 years
DTP combined vaccine (4th dose), MMR combined vaccine (2nd dose), Polio booster
11-13 years
Rubella (German measles)
13 years
Tuberculosis (BCG)
15 years
Tetanus and Diptheria – booster
Polio booster.

7. How Vaccines Work
Small, safe doses are administered either by injection or orally.
This promotes the primary response by clonal selection
Second injections may be given to strengthen the response
The B and T lymphocytes make memory cells, which will divide rapidly by mitosis (clonal expansion) if you come into contact with the infection
Vaccines vary in how long they last
Cholera 2years
Tetanus 10 years
Polio or MMR may last for life

8. Herd Immunity
This is the protection gained by a community when vaccination rates are very high usually over 85%
They reduce epidemics (local or national infection spreading rapidly)
Pandemics –infection across the world will trigger international vaccination programmes such as the SARS (severe acute respiratory syndrome) and bird flu epidemics.

9. Spanish Flu
The Spanish flu pandemic caused over 50 million deaths which was over 3% of the world population and more than world war1.
Flu normally kills very young and elderly people but Spanish flu was most deadly to younger/healthy people. Researchers think that the virus provoked a huge cytokine response called a cytokine storm which causes a massive accumulation of tissue fluid and WBC at sites of infection such as lungs.

10. Control of disease by vaccination
Important features of a successful vaccination programme
Development of a suitable vaccine
Few if any side effects
The mechanisms to produce, store and transport the vaccine
Administering vaccine at the right time and right group appropriately
Vaccinate the vast majority (high risk groups) HERD IMMUNITY

11. Small pox the last jenneration!
Reason for the successful eradication of smallpox
Explanation
Simple safe vaccine
Live vaccine especially effective and persists in the body longer
Easy to produce and administer
Virus was genetically stable
Lethal nature of disease
Symptoms easily recognised – stops spread
Virus doesn’t remain in body after infection
No host/vector organism involved
A coordinated worldwide vaccination programme

12. Measles lower success rate in control by vaccination
Vaccine is only 95% effective
Measles antigens are complex
Some children do not respond effectively to the measles vaccine – need boosters
Parental concern over MMR vaccine

13. Cholera and TB
Cholera
Remains in intestines beyond reach of antibodies
Oral vaccine being developed
Mobile populations
Antigenic drift and antigenic shift is rapid
Tuberculosis
Increase in HIV – more opportunistic infections of TB
Increasing poverty – overcrowding due to war / unrest
Mobile populations
Increasingly older populations

14. Medications Drugs can treat disease in a number of ways
Pain killers e.g. aspirin, morphine
Antibiotics to destroy pathogens e.g. penicillin
Hormones e.g. insulin
Restore functions and adjust processes in the body e.g. statins reduce blood cholesterol, digoxin from foxgloves can modify the heart beat in atrial fibrillation

15. Sources of Drugs Many are naturally occurring
Aspirin comes from willow bark
Morphine from opium poppies
Penicillin from mould
Vancomycin is a new powerful antibiotic from a soil fungus
We need to maintain biodiversity as these organisms may be potential sources of new drugs

16. Pharmacogenetics
Pharmaceutical companies can also design and modify drugs using huge data bases of information about the action of various chemicals
They can also be personalised to your genetic make up. Some people respond negatively to a drug that can help others. Understanding how different genes interact with a drug can be very important to prevent damaging side effects
Pharmacogenetics

17. Plenary
What about the control of malaria? – use your books to find out why it is hard to control through vaccination.
Try exam questions
Complete card loop in class.