3.8 Clinical Trials of Vaccines and Drugs

Question 1

State the purpose of clinical drug trials.

Answer 1

Vaccines and drugs are subjected to clinical trials to establish their safety and effectiveness before being licensed for use.

Question 2

Identify the four key protocols to be built into the design of a clinical drug trial.

Answer 2

Randomised groups
Double blind
Placebo group
Group size

Question 3

Randomised groups

Answer 3

Randomised groups : The subjects (participants) in clinical trials are divided into groups in a randomised way to reduce bias in the distribution of characteristics such as age and gender.

Question 4

Double blind

Answer 4

Double blind : In a double-blind trial neither the subjects (participants) nor the researchers know which group subjects are in to prevent biased interpretation of the results.

Question 5

Placebo group

Answer 5

Placebo group : One group of the subjects (participants) receives the vaccine or drug while the second group receives a placebo-control to ensure valid comparisons.

Question 6

Group size

Answer 6

Group size : Group size is important in reducing experimental error and establishing statistical significance. At the end of the trial, results from the two groups, which must be of a suitable size to reduce the magnitude of experimental error, are compared to determine whether there are any statistically significant differences between the groups.

Question 7

Explain the value of using error bars to examine clinical trial results.

Answer 7

Error (uncertainty) bars are used to determine significant differences between mean results. The degree of overlap between the error (uncertainty) bars indicates the significance of the statistical difference between the results.

Question 8

What is an error bar

Answer 8

An error bar is a line through a point on a graph, parallel to one of the axes, which represents the uncertainty or variation of the corresponding coordinates of the point
In biology, the error bars most often represent the standard deviation of a data set.

Question 9

Overlap

Answer 9

When standard deviation errors bars overlap quite a bit, its a clue that the difference is not statistically significant. You must actually perform a statistical test to draw a conclusion

Question 10

Less overlap

Answer 10

When standard deviation errors bars overlap even less, its a clue that the difference is probably not statistically significant. You must actually perform statistical test to draw a conclusion

Question 11

No overlap

Answer 11

When standard deviation error bars do not overlap. Its a clue that the difference may be significant, but you cannot be sure. You must actually perform statistical test to draw a conclusion