Assessment 1
Question 1
Which of the following statements is/are correct?
Select one or more:
| A. Post-licensure AEFI surveillance is important because vaccine adverse reactions with delayed onset may not be known at the time of vaccine licensure. | |
| B. Pre-licensure trials do not detect common minor vaccine reactions. These are discovered in Post-licensure AEFI surveillance. | |
| C. Post-licensure AEFI surveillance is important because subpopulations commonly excluded in clinical trials (e.g. persons with underlying medical conditions, premature infants) are included in immunization programmes and may be at increased risk of AEFIs. | |
| D. Post-licensure AEFI surveillance of large cohorts may detect uncommon or rare severe vaccine reactions that were not known at the time of vaccine licensure. | |
| E. Post-licensure clinical trials are not required to assess the effects of changes in vaccine formulation or vaccine strain. | |
| F. Post-licensure AEFI surveillance does not identify errors in vaccine administration practices. |
Answers A, C and D are correct.
The key point is that in pre-licensure clinical trials, the sensitivity of detection is low for:
- uncommon or rare adverse reactions, or
- reactions with delayed onset, or
- reactions affecting subgroups excluded from clinical trials.
Continuous post-licensure monitoring of vaccine safety is therefore critical to identify and evaluate such adverse events, particularly when there are changes in vaccine formulation or vaccine strain.