HI 301 Epidemiology FINAL READINESS GUIDE Q & S 2025/2026

1. Which study design is most appropriately used to
determine the effectiveness of a new vaccine?
 - A) Case-control study
 - B) Cohort study
 - C) Randomized controlled trial (RCT)
 - D) Cross-sectional study
 - Correct Answer: C) Randomized controlled trial
(RCT)
 Rationale: RCTs are the gold standard for assessing
the causal relationship between an intervention and an
outcome, especially for vaccine effectiveness.
2. The concept of herd immunity is most closely
associated with which type of prevention?
 - A) Primary prevention
 - B) Secondary prevention
 - C) Tertiary prevention
 - D) Quaternary prevention
 - Correct Answer: A) Primary prevention
 Rationale: Herd immunity prevents the spread of
disease among vulnerable populations through vaccination.
3. An epidemiologist discovers that a particular disease
has a higher prevalence in smokers than non-smokers.
Which measure can best quantify this relationship?
 - A) Prevalence ratio
 - B) Relative risk
 - C) Attributable risk
 - D) Odds ratio