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BBH 440 – Principles of Epidemiology (Final
Exam) QUESTIONS AND CORRECT DETAILED SOLUTIONS
WITH RATIONALES LATEST THIS YEAR (2026-2027)
Summarized exam coverage for BBH 440 – Principles of Epidemiology (Final Exam) , followed
by 250 randomized, scenario-based MCQs with answers and italicized rationales. No domains
or subtopics are quoted.
Summarized Exam Coverage (BBH 440 Final)
Core topics: Epidemiologic fundamentals (definition, distribution vs. determinants, descriptive
vs. analytic), disease frequency (endemic, epidemic, pandemic, epizootic), transmission
dynamics (direct, indirect, vehicle-borne, vector-borne, airborne, fomites), natural history of
disease (incubation period, prodromal period, fastigium, defervescence, convalescence), host-
agent-environment triad, immunity types (natural/artificial, active/passive, herd immunity),
study designs (case studies, cross-sectional, ecological, case-control, cohort, RCT, meta-analysis),
measures of morbidity and mortality (incidence, prevalence, attack rate, crude/age-
specific/cause-specific mortality rates, case fatality rate), measures of association (relative risk,
odds ratio, attributable risk, population attributable risk), screening test evaluation (sensitivity,
specificity, PPV, NPV, likelihood ratios, lead time bias, length bias), bias and confounding
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(selection, information, recall, confounding), causal inference (Hill’s criteria), and statistical
inference (p-values, confidence intervals, type I/II errors, power).
250 Randomized BBH 440 Final Exam MCQs
1. A researcher wants to describe the number of new COVID-19 cases per 100,000 people in
Pennsylvania during October 2025. This measure is best described as:
A) Prevalence
B) Incidence proportion
C) Attack rate
D) Case fatality rate
Answer: B Incidence measures new cases occurring in a population over a specified time period,
while prevalence captures existing cases at a point in time.
2. A disease has a 95% sensitivity and 90% specificity. If the prevalence is 1%, what is the
positive predictive value?
A) Approximately 8.8%
B) 95%
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C) 90%
D) 50%
Answer: A In low-prevalence populations, even highly sensitive tests yield low PPV because most
positive results will be false positives; calculation requires Bayes’ theorem.
3. A study finds a relative risk of 2.5 for lung cancer among smokers compared to non-smokers,
with a 95% confidence interval of 1.8 to 3.2. This means:
A) The result is not statistically significant
B) Smokers have 2.5 times the risk of lung cancer compared to non-smokers
C) The risk is decreased by 150%
D) The association is due to chance
Answer: B RR of 2.5 indicates exposed group has 2.5 times the risk; CI excluding 1.0 confirms
statistical significance.
4. During a foodborne illness outbreak, all 50 people who ate potato salad at a picnic became ill
within 6 hours. No one who avoided potato salad became ill. This outbreak pattern is best
described as:
A) Propagated epidemic
B) Point source epidemic
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C) Continuous common source
D) Sporadic
Answer: B A point source epidemic arises from a single exposure event with cases occurring
within a narrow time window, as seen with contaminated food.
5. A newborn receives antibodies through breastfeeding. This type of immunity is classified as:
A) Artificial active immunity
B) Natural passive immunity
C) Natural active immunity
D) Artificial passive immunity
Answer: B Natural passive immunity involves transfer of pre-formed antibodies from mother to
infant through breast milk or placenta, without the infant’s immune system mounting a
response.
6. A testing campaign identifies 80 true positive cases, 20 false negatives, 900 true negatives,
and 100 false positives. The sensitivity is:
A) 80%
B) 90%
C) 75%
BBH 440 – Principles of Epidemiology (Final
Exam) QUESTIONS AND CORRECT DETAILED SOLUTIONS
WITH RATIONALES LATEST THIS YEAR (2026-2027)
Summarized exam coverage for BBH 440 – Principles of Epidemiology (Final Exam) , followed
by 250 randomized, scenario-based MCQs with answers and italicized rationales. No domains
or subtopics are quoted.
Summarized Exam Coverage (BBH 440 Final)
Core topics: Epidemiologic fundamentals (definition, distribution vs. determinants, descriptive
vs. analytic), disease frequency (endemic, epidemic, pandemic, epizootic), transmission
dynamics (direct, indirect, vehicle-borne, vector-borne, airborne, fomites), natural history of
disease (incubation period, prodromal period, fastigium, defervescence, convalescence), host-
agent-environment triad, immunity types (natural/artificial, active/passive, herd immunity),
study designs (case studies, cross-sectional, ecological, case-control, cohort, RCT, meta-analysis),
measures of morbidity and mortality (incidence, prevalence, attack rate, crude/age-
specific/cause-specific mortality rates, case fatality rate), measures of association (relative risk,
odds ratio, attributable risk, population attributable risk), screening test evaluation (sensitivity,
specificity, PPV, NPV, likelihood ratios, lead time bias, length bias), bias and confounding
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(selection, information, recall, confounding), causal inference (Hill’s criteria), and statistical
inference (p-values, confidence intervals, type I/II errors, power).
250 Randomized BBH 440 Final Exam MCQs
1. A researcher wants to describe the number of new COVID-19 cases per 100,000 people in
Pennsylvania during October 2025. This measure is best described as:
A) Prevalence
B) Incidence proportion
C) Attack rate
D) Case fatality rate
Answer: B Incidence measures new cases occurring in a population over a specified time period,
while prevalence captures existing cases at a point in time.
2. A disease has a 95% sensitivity and 90% specificity. If the prevalence is 1%, what is the
positive predictive value?
A) Approximately 8.8%
B) 95%
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C) 90%
D) 50%
Answer: A In low-prevalence populations, even highly sensitive tests yield low PPV because most
positive results will be false positives; calculation requires Bayes’ theorem.
3. A study finds a relative risk of 2.5 for lung cancer among smokers compared to non-smokers,
with a 95% confidence interval of 1.8 to 3.2. This means:
A) The result is not statistically significant
B) Smokers have 2.5 times the risk of lung cancer compared to non-smokers
C) The risk is decreased by 150%
D) The association is due to chance
Answer: B RR of 2.5 indicates exposed group has 2.5 times the risk; CI excluding 1.0 confirms
statistical significance.
4. During a foodborne illness outbreak, all 50 people who ate potato salad at a picnic became ill
within 6 hours. No one who avoided potato salad became ill. This outbreak pattern is best
described as:
A) Propagated epidemic
B) Point source epidemic
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C) Continuous common source
D) Sporadic
Answer: B A point source epidemic arises from a single exposure event with cases occurring
within a narrow time window, as seen with contaminated food.
5. A newborn receives antibodies through breastfeeding. This type of immunity is classified as:
A) Artificial active immunity
B) Natural passive immunity
C) Natural active immunity
D) Artificial passive immunity
Answer: B Natural passive immunity involves transfer of pre-formed antibodies from mother to
infant through breast milk or placenta, without the infant’s immune system mounting a
response.
6. A testing campaign identifies 80 true positive cases, 20 false negatives, 900 true negatives,
and 100 false positives. The sensitivity is:
A) 80%
B) 90%
C) 75%
