During an outbreak, two groups of people are exposed to the same live pathogen. The pathogen carries an antigen contained in a vaccine previously given to one of the groups.
The table shows the mean antibody concentration in each group at different times after exposure.
| Time after exposure (days) | Previously vaccinated group (arbitrary units) | Not previously vaccinated group (arbitrary units) |
|---|---|---|
| 0 | 2 | 2 |
| 3 | 40 | 8 |
| 7 | 120 | 35 |
Compare the results and explain how the response in the previously vaccinated group could reduce the likelihood of serious symptoms.
87 exam-style questions on Edexcel GCSE Biology 5.3 Immune system and medicines, covering 5.3.1 The specific immune system, 5.3.2 Response to immunisation, 5.3.3 Advantages and disadvantages of immunisation, 5.3.4 Antibiotics and bacterial infections, 5.3.5 Aseptic techniques in culturing, 5.3.6 Cross-sectional areas of cultures, 5.3.7 Stages of developing new medicines, and 5.3.8 Production of monoclonal antibodies. Each one has a worked solution and a mark scheme showing where the marks go.