Vaccines

Question 1

Active immunity

Answer 1

Immune system makes its own antibodies after being stimulated by an antigen. This can be natural (after catching a disease) or artificial (after given a vaccination)

Question 2

Passive immunity

Answer 2

Given antibodies made by a different organism. This can be natural (baby becomes immune due to antibodies it receives from mother’s placenta and breast milk) or artificial (after being injected with antibodies from someone else)

Question 3

How do vaccines work?

Answer 3

• Dead/weakened pathogen contain antigens, stimulating primary immune response
• When pathogen infects us, we already have correct antibodies, memory B and T cells
• Undergo secondary immune response where you don’t feel symptoms
• Reduce the occurrence of the disease so those not vaccinated are also less likely to catch the disease (herd immunity)

Question 4

Ethical issues surrounding use of vaccines

Answer 4

• Vaccines are tested on animals before being tested on humans
• Animal based substances may be used to produce a vaccine
• Testing vaccines on humans can be risky (volunteers may put themselves at unnecessary risk of contracting the disease because they think they’re fully protected)
• Risk of side effects
• Decisions about who would be the first to receive it

Question 5

What is antigenic variation?

Answer 5

Where pathogens change their surface antigens due to changes in their genes

Question 6

How can we avoid the effects of antigenic variation when vaccinating?

Answer 6

• Developing new vaccines every year and choosing the one most effective against the recently circulating viruses
• Governments and health authorities implement a programme of vaccination