In a retrospective case-control study, the initial case group is composed of persons
with the disease
without the disease.
with the risk factor under investigation
without the risk factor under investigation
In aretrospective case-control study, cases and controls are selected based on disease status. The case group is composed of individuals whohave the disease(cases), while the control group consists of individualswithout the disease. This design allows researchers to look back in time to assess exposure to potential risk factors.
Step-by-Step Justification:
Selection of Cases and Controls:
Cases: Individuals who already have the disease.
Controls: Individuals without the disease but similar in other aspects.
Direction of Study:
A retrospective study movesbackwardfrom the disease outcome to investigate potential causes or risk factors​.
Data Collection:
Uses past medical records, interviews, and laboratory results to determine past exposures.
Common Use:
Useful for studyingrare diseasessince cases have already occurred, making it cost-effective compared to cohort studies.
Why Other Options Are Incorrect:
B. without the disease:(Incorrect) This describes the control group, not the case group.
C. with the risk factor under investigation:(Incorrect) Risk factors are identified after selecting cases and controls.
D. without the risk factor under investigation:(Incorrect) The study investigates whether cases had prior exposure, not whether they lacked a risk factor.
CBIC Infection Control References:
APIC Text, Chapter on Epidemiologic Study Design​.
In the current year, cases of tuberculosis (TB) among foreign-born persons accounted for the majority of new TB cases in the United States. The number of states with greater than 50% of cases among foreign-born persons increased from four cases ten years ago to 22 cases in the current year. This information can BEST be used to
heighten awareness among Emergency Department staff.
inform staff who are foreign-born.
educate patients and visitors.
review the TB exposure control plan.
1 and 2 only.
1 and 4 only.
2 and 3 only.
3 and 4 only.
The correct answer is B, "1 and 4 only," indicating that the information can best be used to heighten awareness among Emergency Department (ED) staff and review the TB exposure control plan. According to the Certification Board of Infection Control and Epidemiology (CBIC) guidelines, tuberculosis (TB) remains a significant public health concern, particularly with the increasing proportion of cases among foreign-born persons in the United States. The data showing a rise from four to 22 states with over 50% of TB cases among foreign-born individuals highlights an evolving epidemiological trend that warrants targeted infection prevention strategies (CBIC Practice Analysis, 2022, Domain II: Surveillance and Epidemiologic Investigation, Competency 2.1 - Conduct surveillance for healthcare-associated infections and epidemiologically significant organisms).
Heightening awareness among ED staff (option 1) is critical because the ED is often the first point of contact for patients with undiagnosed or active TB, especially those from high-prevalence regions. Increased awareness can improve early identification, isolation, and reporting of potential cases. Reviewing the TB exposure control plan (option 4) is equally important, as it allows the infection preventionist to assess and update protocols—such as ventilation, personal protective equipment (PPE) use, and screening processes—to address the heightened risk posed by the growing number of cases among foreign-born individuals (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.2 - Implement measures to prevent transmission of infectious agents).
Option 2 (inform staff who are foreign-born) is not the best use of this data, as the information pertains to patient demographics rather than staff risk, and targeting staff based on their origin could be inappropriate without specific exposure evidence. Option 3 (educate patients and visitors) is a general education strategy but less directly actionable with this specific epidemiological data, which is more relevant to healthcare worker preparedness and facility protocols. Combining options 1 and 4 aligns with CBIC’s emphasis on using surveillance data to guide prevention and control measures, ensuring a proactive response to the increased TB burden (CBIC Practice Analysis, 2022, Domain II: Surveillance and Epidemiologic Investigation, Competency 2.5 - Use data to guide infection prevention and control strategies).
An infection preventionist is reviewing employee health immunization policies. What is the recommendation for tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) for a 55-year-old nurse who received all childhood vaccinations?
One dose of Tdap vaccine
Two doses of Tdap vaccine at least 14 days apart
Two doses of Tdap vaccine at least 28 days apart
No additional vaccination is recommended
The correct answer is A, "One dose of Tdap vaccine," as this is the recommended immunization for a 55-year-old nurse who received all childhood vaccinations. According to the Certification Board of Infection Control and Epidemiology (CBIC) guidelines, which align with recommendations from the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices (ACIP), adults who have completed a primary series of childhood vaccinations (typically 5 doses of DTaP or DTP) should receive a single booster dose of Tdap if they have not previously received it. This is especially critical for healthcare personnel, such as a 55-year-old nurse, due to their increased risk of exposure to pertussis and the need to protectvulnerable patients (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.2 - Implement measures to prevent transmission of infectious agents). The Tdap vaccine, which protects against tetanus, diphtheria, and pertussis, is recommended once between ages 11-64, with a preference for administration in early adulthood (e.g., 19-26 years) or as soon as feasible for older adults, including this 55-year-old nurse, to ensure immunity against pertussis, which wanes over time. For individuals aged 65 and older, Tdap is still recommended if not previously received, though Tdap is preferred over Td (tetanus and diphtheria only) for healthcare workers to address pertussis risk.
Option B (two doses of Tdap vaccine at least 14 days apart) and Option C (two doses of Tdap vaccine at least 28 days apart) are not standard recommendations for adults with a complete childhood vaccination history. Multiple doses are typically reserved for individuals with incomplete primary series or specific high-risk conditions, not for this scenario. Option D (no additional vaccination is recommended) is incorrect because, even with a complete childhood series, a Tdap booster is advised for healthcare workers to maintain protection, especially given the nurse’s occupational exposure risks (CDC Immunization Schedules, 2024). After receiving the Tdap booster, a Td booster every 10 years is recommended to maintain tetanus and diphtheria immunity, but the initial Tdap dose is the priority for this nurse.
The recommendation for one Tdap dose aligns with CBIC’s emphasis on evidence-based immunization policies to prevent transmission of vaccine-preventable diseases in healthcare settings (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.1 - Collaborate with organizational leaders). This ensures the nurse is protected and contributes to herd immunity, reducing the risk of pertussis outbreaks in the healthcare environment.
Peripherally inserted central catheter (PICC)-associated bloodstream infections (BSIs) have been increasing over the past four months. Which of the following interventions is MOST likely to have contributed to the increase?
Use of chlorhexidine skin antisepsis during insertion of the PICC
Daily bathing adult intensive care unit patients with chlorhexidine
Replacement of the intravenous administration sets every 72 hours
Use of a positive pressure device on the PICC
Peripherally inserted central catheter (PICC)-associated bloodstream infections (BSIs) are a significant concern in healthcare settings, and identifying factors contributing to their increase is critical for infection prevention. The Certification Board of Infection Control and Epidemiology (CBIC) emphasizes the "Surveillance and Epidemiologic Investigation" and "Prevention and Control of Infectious Diseases" domains, which align with the Centers for Disease Control and Prevention (CDC) guidelines for preventing intravascular catheter-related infections. The question asks for the intervention most likely to have contributed to the rise in PICC-associated BSIs over four months, requiring an evaluation of each option based on evidence-based practices.
Option C, "Replacement of the intravenous administration sets every 72 hours," is the most likely contributor to the increase. The CDC’s "Guidelines for the Prevention of Intravascular Catheter-Related Infections" (2017) recommend that intravenous administration sets (e.g., tubing for fluids or medications) be replaced no more frequently than every 72-96 hours unless clinically indicated (e.g., contamination or specific therapy requirements). Frequent replacement, such as every 72 hours as a routine practice, can introduce opportunities for contamination during the change process, especially if aseptic technique is not strictly followed. Studies cited in the CDC guidelines, including those by O’Grady et al. (2011), indicate that unnecessary manipulation of catheter systems increases the risk of introducing pathogens, potentially leading to BSIs. A change to a 72-hour replacement schedule, if not previously standard, could explain the observed increase over the past four months.
Option A, "Use of chlorhexidine skin antisepsis during insertion of the PICC," is a recommended practice to reduce BSIs. Chlorhexidine, particularly in a 2% chlorhexidine gluconate with 70% alcohol solution, is the preferred skin antiseptic for catheter insertion due to its broad-spectrum activity and residual effect, as supported by the CDC (2017). This intervention should decrease, not increase, infection rates, making it an unlikely contributor. Option B, "Daily bathing adult intensive care unit patients with chlorhexidine," is another evidence-based strategy to reduce healthcare-associated infections, including BSIs, by decolonizing the skin of pathogens like Staphylococcus aureus. The CDC and SHEA (Society for Healthcare Epidemiology of America) guidelines (2014) endorse chlorhexidine bathing in intensive care units, suggesting it should lower, not raise, BSI rates. Option D, "Use of a positive pressure device on the PICC," aims to prevent catheter occlusion and reduce the need for frequent flushing, which could theoretically decrease infection risk by minimizing manipulation. However, there is no strong evidence linking positive pressure devices to increased BSIs; if improperly used or maintained, they might contribute marginally, but this is less likely than the impact of frequent tubing changes.
The CBIC Practice Analysis (2022) and CDC guidelines highlight that deviations from optimal catheter maintenance practices, such as overly frequent administration set replacements, can increase infection risk. Given the four-month timeframe and the focus on an intervention’s potential negative impact, Option C stands out as the most plausible contributor due to the increased manipulation and contamination risk associated with routine 72-hour replacements.
In which of the following ways is human immunodeficiency virus similar to the Hepatitis B virus?
The primary mechanism of transmission for both is maternal-fetal
Needlestick exposure leads to a high frequency of healthcare worker infection
Transmission may occur from asymptomatic carriers
The risk of infection from mucous membrane exposure is the same
The human immunodeficiency virus (HIV) and Hepatitis B virus (HBV) are both bloodborne pathogens that pose significant risks in healthcare settings, and understanding their similarities is crucial for infection prevention and control. The Certification Board of Infection Control and Epidemiology (CBIC) emphasizes the importance of recognizing transmission modes and implementing appropriate precautions in the "Prevention and Control of Infectious Diseases" domain, aligning with guidelines from the Centers for Disease Control and Prevention (CDC). Comparing these viruses involves evaluating their epidemiology, transmission routes, and occupational risks.
Option C, "Transmission may occur from asymptomatic carriers," is the correct answer. Both HIV and HBV can be transmitted by individuals who are infected but show no symptoms, making asymptomatic carriage a significant similarity. For HBV, chronic carriers (estimated at 257 million globally per WHO, 2019) can transmit the virus through blood, semen, or other bodily fluids without overt signs of disease. Similarly, HIV-infected individuals can remain asymptomatic for years during the latent phase, yet still transmit the virus through sexual contact, blood exposure, or perinatal transmission. The CDC’s "Guidelines for Prevention of Transmission of HIV and HBV to Healthcare Workers" (1987, updated 2011) and "Epidemiology and Prevention of Viral Hepatitis" (2018) highlight this shared characteristic, underscoring the need for universal precautions regardless of symptom status.
Option A, "The primary mechanism of transmission for both is maternal-fetal," is incorrect. While maternal-fetal transmission (perinatal transmission) is a significant route for both HIV and HBV—occurring in 5-10% of cases without intervention for HBV and 15-45% for HIV without antiretroviral therapy—it is not the primary mechanism. For HBV, the primary mode is horizontal transmission through unprotected sexual contact or percutaneous exposure (e.g., needlesticks), accounting for the majority of cases. For HIV, sexual transmission and intravenous drug use are the leading modes globally, with maternal-fetal transmission being a smaller proportion despite its importance. Option B, "Needlestick exposure leads to a high frequency of healthcare workerinfection," is partially true but not a precise similarity. Needlestick exposures carry a high risk for HBV (transmission risk ~30% if the source is HBeAg-positive) and a lower risk for HIV (~0.3%), but the frequency of infection among healthcare workers is significantly higher for HBV due to its greater infectivity and stability outside the host. This makes the statement more characteristic of HBV than a shared trait. Option D, "The risk of infection from mucous membrane exposure is the same," is false. The risk of HIV transmission via mucous membrane exposure (e.g., splash to eyes or mouth) is approximately 0.09%, while for HBV it is higher (up to 1-2% depending on viral load and exposure type), reflecting HBV’s greater infectivity.
The CBIC Practice Analysis (2022) and CDC guidelines emphasize the role of asymptomatic transmission in shaping infection control strategies, such as routine testing and post-exposure prophylaxis. This shared feature of HIV and HBV justifies Option C as the most accurate similarity.
An infection preventionist is evaluating a new catheter that may decrease the rate of catheter-associated urinary tract infections. Which of the following provides the BEST information to support the selection of this catheter?
Staff member preference and product availability
Product materials and vendor information
Value analysis and information provided by the manufacturer
Cost benefit analysis and safety considerations
The correct answer is D, "Cost benefit analysis and safety considerations," as this provides the best information to support the selection of a new catheter aimed at decreasing the rate of catheter-associated urinary tract infections (CAUTIs). According to the Certification Board of Infection Control and Epidemiology (CBIC) guidelines, selecting medical devices like catheters for infection prevention involves a comprehensive evaluation that balances efficacy, safety, and economic impact. A cost-benefit analysis assesses the financial implications (e.g., reduced infection rates leading to lower treatment costs) against the cost of the new catheter, while safety considerations ensure the device minimizes patient risk, such as reducing biofilm formation or irritation that contributes to CAUTIs (CBIC Practice Analysis, 2022, Domain III: Infection Prevention and Control, Competency 3.3 - Ensure safe reprocessing of medical equipment). This dual focus provides evidence-based data to justify the catheter’s adoption, aligning with the goal of improving patient outcomes and reducing healthcare-associated infections (HAIs).
Option A (staff member preference and product availability) is subjective and logistical rather than evidence-based, making it insufficient for a decision that impacts infection rates. Option B (product materials and vendor information) offers technical details but lacks the broader context of efficacy and cost-effectiveness needed for a comprehensive evaluation. Option C (value analysis and information provided by the manufacturer) includes a structured assessment of value, but it may be biased toward the manufacturer’s claims and lacks the independent safety and cost-benefit perspective critical for infection prevention decisions.
The emphasis on cost-benefit analysis and safety considerations reflects CBIC’s priority on using data-driven and patient-centered approaches to select interventions that enhance infection control (CBIC Practice Analysis, 2022, Domain II: Surveillance and Epidemiologic Investigation, Competency 2.5 - Use data to guide infection prevention and control strategies). This approach ensures the catheter’s selection is supported by robust evidence, optimizing both clinical and economic outcomes in the prevention of CAUTIs.
A family, including an infant of 8 months, is going on a vacation to Europe. An infection preventionist would recommend:
Exposure to rabies should be avoided.
Family members should be vaccinated for yellow fever.
The infant should not travel until at least 12 months of age.
Family immunization records should be reviewed by their provider.
When advising a family, including an 8-month-old infant, planning a vacation to Europe, an infection preventionist (IP) must consider travel-related health risks and vaccination recommendations tailored to the destination and age-specific guidelines. The Certification Board of Infection Control and Epidemiology (CBIC) emphasizes the "Education and Training" domain, which includes providing evidence-based advice to prevent infections, aligning with the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) travel health recommendations.
Option D, "Family immunization records should be reviewed by their provider," is the most appropriate recommendation. Europe, as a region, includes countries with varying health risks, but it is generally considered a low-risk area for many vaccine-preventable diseases compared to tropical regions. The CDC’s "Travelers’ Health" guidelines (2023) recommend that all travelers, including infants, have their immunization status reviewed by a healthcare provider prior to travel to ensure compliance with routine vaccinations (e.g., measles, mumps, rubella [MMR], diphtheria, tetanus, pertussis [DTaP], and polio) and to assess any destination-specific needs. For an 8-month-old, the review would confirm that the infant has received age-appropriate vaccines (e.g., the first doses of DTaP, Hib, PCV, and IPV, typically starting at 2 months) and is on schedule for the 6- and 12-month doses. This step ensures the family’s overall protection and identifies any gaps, making it a proactive and universally applicable recommendation.
Option A, "Exposure to rabies should be avoided," is a general travel safety tip applicable to any destination where rabies is endemic (e.g., parts of Eastern Europe or rural areas with wildlife). However, rabies risk in most European countries is low, and pre-exposure vaccination is not routinely recommended for travelers unless specific high-risk activities (e.g., handling bats) are planned. The CDC advises avoiding animal bites rather than vaccinating unless indicated, making this less specific and urgent than a records review. Option B, "Family members should be vaccinated for yellow fever," is incorrect. Yellow fever is not endemic in Europe, and vaccination is not required or recommended for travel to any European country. The WHO International Health Regulations (2005) and CDC list yellow fever vaccination as mandatory only for travelers from or to certain African and South American regions, rendering this irrelevant. Option C, "The infant should not travel until at least 12 months of age," lacks a clear evidence base. While some vaccines (e.g., MMR) are typically given at 12 months, the 8-month-old can travel safely if up-to-date on age-appropriate immunizations. The CDC allows travel for infants as young as 6 weeks with medical clearance, and delaying travel to 12 months is not a standard recommendation unless specific risks (e.g., disease outbreaks) are present, which are not indicated here.
The CBIC Practice Analysis (2022) and CDC Travelers’ Health resources prioritize pre-travel health assessments, including immunization reviews, as the foundation for safe travel. Option D ensures a comprehensive approach tailored to the family’s needs, making it the best recommendation for a trip to Europe.
At a facility with 10.000 employees. 5,000 are at risk for bloodbome pathogen exposure. Over the past five years, 100 of the 250 needlestick injuries involved exposure to bloodborne pathogens, and 2% of exposed employees seroconverted. How many employees became infected?
1
2
5
10
To determine the number of employees whoseroconverted(became infected) after aneedlestick exposure, we use the given data:
Total Needlestick Injuries:250
Needlestick Injuries Involving Bloodborne Pathogens:100
Seroconversion Rate:2%
Calculation:
A black text with black numbers
AI-generated content may be incorrect.
Why Other Options Are Incorrect:
A. 1:Incorrect calculation;2% of 100 is 2, not 1.
C. 5:Overestimates the actual number of infections.
D. 10:Exceeds the calculated value based on given data.
CBIC Infection Control References:
APIC Text, "Occupational Exposure and Seroconversion Risks"​.
APIC Text, "Bloodborne Pathogens and Needlestick Injury Prevention"​