Vaccine safety surveillance and AEFI monitoring MCQs With Answer

This MCQ collection on Vaccine safety surveillance and AEFI monitoring is designed for M.Pharm students preparing for higher-level exams in Clinical Research and Pharmacovigilance. It covers core concepts such as definitions and classification of AEFIs, passive and active surveillance systems, signal detection methods, causality assessment frameworks (WHO and Brighton Collaboration), observed-versus-expected analyses, and post‑marketing risk management. Questions emphasize practical scenarios encountered in immunization programs — lot investigations, cold chain issues, cluster detection, and regulatory reporting pathways — and include data interpretation and statistical signal tools like PRR and cohort event monitoring. Use these MCQs to test understanding, identify knowledge gaps, and reinforce evidence‑based approaches to vaccine safety.

Q1. Which of the following best defines an AEFI (Adverse Event Following Immunization)?

• Any adverse reaction proven to be caused by a vaccine
• Any untoward medical occurrence that follows immunization, which may or may not be causally related to vaccine
• Only severe events requiring hospitalization after vaccination
• An expected local reaction at injection site only

Correct Answer: Any untoward medical occurrence that follows immunization, which may or may not be causally related to vaccine

Q2. Which statement correctly describes active vaccine safety surveillance?

• It relies solely on spontaneous reports from healthcare professionals and the public
• It involves proactively seeking cases through cohort monitoring, sentinel sites, or record linkage
• It is limited to regulatory inspections of vaccine manufacturers
• It only records events reported within clinical trials

Correct Answer: It involves proactively seeking cases through cohort monitoring, sentinel sites, or record linkage

Q3. Which option is NOT one of the standard WHO causality assessment categories for AEFI?

• Certain
• Probable/Likely
• Possible
• Definitely related

Correct Answer: Definitely related

Q4. Which organization is best known for developing standardized case definitions and diagnostic certainty levels for AEFIs?

• Centers for Disease Control and Prevention (CDC)
• Brighton Collaboration
• European Medicines Agency (EMA)
• Food and Drug Administration (FDA)

Correct Answer: Brighton Collaboration

Q5. VAERS, a passive vaccine safety surveillance system, is maintained by which country?

• United Kingdom
• Canada
• United States
• Australia

Correct Answer: United States

Q6. Which statistical method is commonly used in spontaneous report databases for signal detection by measuring disproportionality?

• Proportional Reporting Ratio (PRR)
• Kaplan–Meier survival analysis
• Linear regression
• Meta-analysis of randomized trials

Correct Answer: Proportional Reporting Ratio (PRR)

Q7. The primary purpose of an observed-versus-expected (O/E) analysis in vaccine safety is to:

• Estimate vaccine efficacy in preventing disease
• Compare the number of observed events after vaccination to the number expected based on background rates
• Calculate vaccine cost-effectiveness
• Replace causality assessment for individual cases

Correct Answer: Compare the number of observed events after vaccination to the number expected based on background rates

Q8. After detecting a potential safety signal in a spontaneous reports database, the immediate next step should be to:

• Withdraw the vaccine from the market immediately
• Validate the signal by verifying case reports, data quality and duplicates
• Publish an alert without further investigation
• Conduct a randomized controlled trial the same day

Correct Answer: Validate the signal by verifying case reports, data quality and duplicates

Q9. According to regulatory definitions, which of the following is NOT considered a “serious” adverse event?

• Death
• Life-threatening reaction
• Mild transient fever not requiring medical attention
• Hospitalization

Correct Answer: Mild transient fever not requiring medical attention

Q10. Which factor is NOT typically part of structured causality assessment for AEFIs?

• Temporal relationship between vaccination and event
• Alternative explanations for the event
• Biological plausibility of association
• Cost of vaccine procurement

Correct Answer: Cost of vaccine procurement

Q11. At the national level in most immunization programs, which body is usually responsible for reviewing serious AEFI reports and providing causality decisions?

• Local clinic nurse manager
• National AEFI expert committee (or National AEFI Committee)
• Vaccine sales team
• Hospital billing office

Correct Answer: National AEFI expert committee (or National AEFI Committee)

Q12. Anaphylaxis after vaccination typically has an onset within which time frame?

• Several weeks after vaccination
• Within minutes to 4 hours, commonly within 30 minutes
• Only after multiple booster doses over months
• After one year of vaccination

Correct Answer: Within minutes to 4 hours, commonly within 30 minutes

Q13. When multiple similar AEFIs cluster in a short time and location, the first priority investigation step is to:

• Identify a common vaccine lot, cold chain or administration practice among cases
• Immediately stop all vaccinations nationwide
• Publish a causal association without analysis
• Blame individual healthcare workers without data review

Correct Answer: Identify a common vaccine lot, cold chain or administration practice among cases

Q14. VigiBase, a global individual case safety report repository, is managed by which organization?

• World Health Organization (WHO) collaborating centre at Uppsala Monitoring Centre (UMC)
• European Pharmacopoeia
• Bill & Melinda Gates Foundation
• International Red Cross

Correct Answer: World Health Organization (WHO) collaborating centre at Uppsala Monitoring Centre (UMC)

Q15. Which of the following is an example of an active surveillance method commonly used for vaccine safety?

• Cohort event monitoring with follow-up of vaccinated individuals
• Voluntary hotline reporting only
• Passive media-based complaint collection
• Annual manufacturer sales audit

Correct Answer: Cohort event monitoring with follow-up of vaccinated individuals

Q16. What is the principal objective of vaccine pharmacovigilance?

• To ensure all vaccines are expensive
• To detect, assess, understand, and prevent adverse events following immunization
• To monitor vaccine advertising effectiveness
• To replace pre-licensure clinical trials

Correct Answer: To detect, assess, understand, and prevent adverse events following immunization

Q17. Which WHO causality category is used when available information is insufficient or contradictory and cannot be supplemented or verified?

• Certain
• Probable
• Unclassifiable (insufficient information)
• Unlikely

Correct Answer: Unclassifiable (insufficient information)

Q18. The Brighton Collaboration case definitions primarily provide guidance on:

• Regulatory approval pathways for vaccines
• Diagnostic certainty levels and standard case definitions for specific adverse events
• Pricing strategies for immunization programs
• Manufacturing sterility testing

Correct Answer: Diagnostic certainty levels and standard case definitions for specific adverse events

Q19. A major limitation of passive AEFI surveillance systems is:

• They always detect all events reliably
• Underreporting and variable quality of reports
• They provide precise incidence rates without further data
• They eliminate the need for active monitoring

Correct Answer: Underreporting and variable quality of reports

Q20. When strengthening evidence for a vaccine safety signal, which of the following is NOT one of the classic Bradford Hill considerations?

• Temporality
• Biological plausibility
• Consistency across studies
• Randomization

Correct Answer: Randomization

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