Vaccine and Antibody Ethics and Evidence
How to give a balanced evaluation of vaccine and monoclonal antibody issues, using ethics, animal testing and trial data such as sample size and controls. Includes the 4-mark exam question, a worked model answer and the examiner trap on one-sided answers.
Chapters (8)
Exam question [4 marks]
A company tests a new vaccine in a clinical trial. Discuss the ethical issues in using vaccines, and evaluate how the design of the trial makes the evidence reliable.
Try it on paper first, then check the mark scheme below. The question is original and was written for this lesson.
Mark scheme
| Mark | Mark point | Also accept | Do not accept |
|---|---|---|---|
| 1 | A control group given a placebo allows comparison, so a difference in illness can be put down to the vaccine (groups allocated at random) | "control group", "placebo", "random allocation", "double blind", "compare with those not vaccinated" | "a control" with no comparison or purpose stated |
| 2 | A large sample size means results are representative / less affected by chance | "many volunteers", "representative of the population", "reduces chance effects" | "a lot of people" with no consequence stated |
| 3 | Benefit of protecting many people (disease prevented / herd immunity) must be weighed against the risk of side effects in a few | "benefit to the population outweighs risk to individuals", "side effects", "balance", "informed consent given by volunteers (with risk stated)" | "vaccines are good" or "vaccines are bad" (opinion only) |
| 4 | Animal testing raises welfare concerns, but is used to check safety before human trials | "harm to animals" with "safety for humans" as the counter-argument | Animal welfare concern with no balancing point |
Marks 1 and 2 are for evaluating the trial design, marks 3 and 4 for ethics. Balanced points score; personal opinion does not. Duration of the trial (to see how long protection lasts and whether rare side effects appear) is an accepted evaluation point in place of sample size or control (max 2 evaluation marks), and monoclonal antibody ethics (use of animals, side effects, cost) are credit-worthy but do not add marks beyond 4. Informed consent from volunteers is also an acceptable ethical point.
Model answer (4/4)
The trial has a control group given a placebo, so the vaccinated group can be compared and a difference in illness put down to the vaccine. A large sample size makes the results representative and less affected by chance. Ethically, the benefit of protecting many people from disease must be weighed against the risk of side effects in a few. Animal testing raises welfare concerns, but is used to check the vaccine is safe before it is given to human volunteers.
Examiner trap
- Writing a one-sided answer
- Not evaluating data (sample size, control, duration)
- Giving personal opinion rather than balanced points
Key terms
- ethics
- animal testing
- side effects
- vaccine trial
- control group
- benefit and risk
- sample size
Lesson notes
A written version of the video, chapter by chapter, for revision. Times link to the video.
0:26Benefits against risks
Ethics questions are about balance. Think of a set of scales. On one side, the benefits. On the other, the risks and the harms. Your job is to put points on both sides, then say how they compare.
0:40Benefits and risks to people
Start with vaccines. The benefit is big. A vaccine stops people catching a disease. If enough people are vaccinated, the pathogen cannot spread easily, which protects even those who cannot be vaccinated. The risk is that a small number of people may suffer side effects. So the ethical question is, does the benefit to many outweigh the risk to a few?
1:05Animal testing
Another issue is animal testing. New vaccines are tested on animals first, to check they are safe before humans receive them. Some people object to animals being harmed. Others argue it protects human volunteers. Monoclonal antibodies raise the same issue, because they are produced using animals. They can also cause side effects, and treatments can be expensive, so there is a fairness question about who gets them.
And volunteers must give informed consent, which means they understand the risks before they agree to take part.
1:40Reading a clinical trial
Now the evidence. How do we know a vaccine works? A clinical trial. Volunteers are split into two groups. One gets the vaccine. The other, the control group, gets a placebo, which contains no active vaccine. Volunteers are allocated at random, so the groups are similar. Then you compare. Because the main difference is the vaccine, a difference in how many people get ill can be put down to the vaccine.
2:10Sample size and evidence
Next, sample size. A trial of ten people could give a result by chance. A large sample is more representative of the whole population, and chance has less effect on the result. Duration matters too. A long trial can show whether the protection lasts, and whether rare side effects appear. So when you evaluate, look for three things. Control group, sample size, duration. Only two evaluation marks are available, so pick the two you can explain best.
3:17Examiner trap and recap
The trap. Giving your own opinion, or only one side. Always give a benefit and a risk, and for data, always comment on the control, the sample size, and the duration.
Recap. Weigh benefit against risk, and judge evidence by its control, sample size and duration. Next, we leave immunity behind and move to exchange with the environment, starting with why surface area to volume ratio matters.
Watch first
This lesson builds on:
- Vaccines, Herd Immunity, Active vs Passive · AQA 7402 · 3.2.4
- Monoclonal Antibodies in Medicine · AQA 7402 · 3.2.4
Keep going
More from 3.2 Cells
- Antigens and Cell Recognition · AQA 7402 · 3.2.4
- Phagocytosis: How Phagocytes Work · AQA 7402 · 3.2.4
- T Lymphocytes: The Cellular Immune Response · AQA 7402 · 3.2.4
- B Cells, Clonal Selection and Antibodies · AQA 7402 · 3.2.4
Independent revision resource, not affiliated with or endorsed by AQA. The exam question is original and was written for this lesson; it is not an AQA question. Spotted an error? Email info@medservatory.com with the lesson code AB-050.