5.6 vaccination

Question 1

What is immunty?

Answer 1

The ability of an organism to resist infection. can be passive or active.

Question 2

what is passive immunity?

Answer 2

The introduction of antibodies from an outside source.
- no direct contact with pathogen necessary
- immunity is immediate
- antibodies are not replaced (as they are not made by the organism) so no memory cells are formed.
- no lasting immunity
EG: anti-venom, fetus acquired immunity

Question 3

What is active immunity?

Answer 3

Produced by stimulating the production of antibodies in the immune system

• direct contact with pathogen is necessary
• immunity takes time to develop
• immunity is, long lasting
• can be natural or artificial

Question 4

What is natural active immunity?

Answer 4

When an individual becomes infected by a disease under normal circumstances. Body produces its own antibodies and continues this for many years.

Question 5

What is artificial active immunity?

Answer 5

Involves inducing an immune response in an organism without them suffering from the effects of the disease. (immunization)

Question 6

What is vaccination?

Answer 6

The introduction of the appropriate disease antigens into the body orally or by injection. The vaccine material contains one or more type of antigen from the pathogen in a small quantity.

Question 7

How does vaccination work?

Answer 7

The introduced antigens stimulate an immune response, but it is a slight response as a small quantity of antigen is added.
Memory cells are produced and circulate in the blood.
If the pathogen enters the body in the future there is an immediate response and antibodies are produced rapidly with few, if any, symptoms of the disease.

Question 8

What are the feature of a successful vaccination programme?

Answer 8

• Vaccine must be economically available in sufficient quantity to immunize the majority of a population
• There must be few side effects so people are not discouraged
• there must be means of producing, storing and transporting the vaccine
• there must be means of administering the vaccine properly at the right time.
• It must be possible to vaccinate the majority of the vulnerable population to produce herd immunity.

Question 9

What is herd immunity?

Answer 9

When a sufficiently large proportion of the population has been vaccinated to make it difficult for a pathogen to spread within that population.

• when the majority of a population is immune it is unlikely that a vulnerable person will come into contact with the disease.
• those who aren’t immune are protected

Question 10

Why is herd immunity important?

Answer 10

• It is never possible to immunize the entirety of a population as vulnerable people cannot be exposed to the pathogen even at a low level
• it is important to interrupt the pathogen spreading by immunizing everyone in a similar time period.

Question 11

Why might vaccination not eliminate disease?

Answer 11

• a defective immune system can mean vaccination doesn’t induce immunity.
• if the disease develops immediately after vaccination immunity levels may not be high enough to prevent it.
• The pathogen may mutate, causing antigenic variability and meaning that memory cells do not recognize the antigens on the pathogen.
• There may be many varieties of a pathogen that cannot all be attacked by one vaccine
• pathogens can hide, by living inside cells or in obscure places (cholera lives in the intestine)
• people may object for religious, medical or ethical reasons.

Question 12

What are the ethical concerns of vaccination?

Answer 12

• New vaccines are usually tested on animals
• vaccines can have long-term side effects
• the clinical testing cause harm to individuals, and it is difficult to know whom they should be tested on.
• Should people be able to opt out, or should vaccination be compulsory?
• Should expensive vaccination schemes continue when the disease is mostly eradicated?