What are vaccines and how do they work?

IDevice Icon Read this information and then do the questions on the next page.

Microorganisms may enter the body and cause illness before the immune system can destroy them.

Vaccinations provide protection from microorganisms by creating antibodies before infection.

A vaccination contains a usually safe form of a disease-causing microorganism.

Vaccination can never be completely safe, since individuals have different degrees of side‑effects from a vaccine.

To prevent epidemics of infectious diseases, it is necessary to vaccinate a high percentage of a population so that the infection cannot spread easily.

There is a conflict between a person's right to decide about vaccination for themselves or their children, as there is a benefit to society as a whole.

New vaccines against influenza have to be developed regularly because the virus changes its antigens very quickly.

It is difficult to develop an effective vaccine against the HIV virus (which causes AIDS) because the virus damages the immune system and has a high mutation rate. Mutations produce changes to its antigens.

Using an example of a vaccination policy make sure that you can say clearly what the issue is, summarise different views that may be held, distinguish what can be done (technical feasibility) from what should be done (values), explain why different courses of action may be taken in different social and economic contexts, identify, and develop, arguments based on the ideas that the right decision is the one which leads to the best outcome for the majority of people involved and that certain actions are never justified because they are unnatural or wrong.