14 Examples from Infectious Disease Epidemiology

Question 1

When is a placebo acceptable as a comparator?

Answer 1

When there is no current standard of care

Question 2

What is generalizability?

Answer 2

Same as external validity
Can the results of this study be expected to be similar in my patients
Is the outcome relevant to my patient population
Does the study compare the new treatment to the treatment currently used for my patients

Question 3

Catastrophic disability

Answer 3

Loss of independence in 3 or more basic levels of care

Often means going to a nursing home or needing an in home nurse

Question 4

Internal validity

Answer 4

How well a study was conducted and how reliable the results from the study are
How assured you can be if there is a difference in the trial that it is due to the vaccine and not something else

Question 5

How to calculate efficacy

Answer 5

((Rate in those who receive placebo) - (rate in those who receive treatment)) / rate in those who receive placebo

Question 6

Phase 1 of clinical studies

Answer 6

20-80 study subjects
Done in healthy adults
Non-comparative study
Aim is to determine safe dose ranges, immunogenicity, and local/systemic reactions

Question 7

Phase 2 of clinical studies

Answer 7

100-300 study subjects
Looking at optimal dose/schedule in target population(s)
Usually controlled
Preliminary assessment of efficacy
Ongoing safety assessment

Question 8

Phase 3 of clinical studies

Answer 8

1000 - > or equal to 3000 study subjects
Immunogenicity/efficacy in target populations
Ongoing safety assessment

Question 9

Phase 4 of clinical studies

Answer 9

Done in the general population so the number of study subjects varies
Looking at “real world” effectiveness
Non-randomized
Immunogenicity/efficacy in unstudied populations
Possible vaccine-vaccine interactions
Expanded safety assessment to look for rare or unexpected adverse events

Question 10

3 principles of informed consent

Answer 10

Voluntary: must be able to consent or refuse without coercion or duress
Capacity: must understand the nature of the trial, the anticipated effect, and the alternatives to participation
Properly informed: fully aware of proposed study procedures and treatments, understand alternatives to participation, and understand the risks

Question 11

2 reasons to register clinical trials

Answer 11

Understanding the potential benefits of a new treatment requires assessment of all clinical trials data
Failure to publish all trial data results in a body of published literature that may not reflect the true performance or safety of a new product in clinical trials

Question 12

Publication bias

Answer 12

The tendency by authors and journals to be more likely to publish positive results