2.7 Host Risk Factors & Emerging Infectious Disease Threats

CBIC Associate Infection Prevention and Control a-IPC

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1 Chapter 1: Introduction & Exam Overview

1.1 About the CBIC a-IPC Certification 1.2 Exam Format, Scoring, & Logistics 1.3 Effective Study Strategies & Preparation Plan

2 Chapter 2: Processes to Identify Infectious Diseases

2.1 Chain of Infection & Pathogen Characteristics 2.2 Diagnostic & Laboratory Testing in IPC 2.3 Identifying Healthcare-Associated Infection Syndromes 2.4 Specimen Collection, Handling, Storage, & Transport 2.5 Colonization, Infection, Contamination, & Pseudo-Infection 2.6 Prophylactic, Empiric, & Therapeutic Antimicrobial Use 2.7 Host Risk Factors & Emerging Infectious Disease Threats

3 Chapter 3: Surveillance and Epidemiologic Investigation

3.1 Surveillance Methods & Program Design 3.2 Epidemiological Calculations & Rate Metrics 3.3 Outbreak Investigation Protocols & Epidemic Curves 3.4 NHSN Definitions & Standardized Infection Ratios (SIR) 3.5 Descriptive Statistics & Presenting Surveillance Data 3.6 Surveillance Across the Care Continuum 3.7 Notifiable Disease Reporting, Data Sources, & Registries 3.8 Data Validation & Surveillance Program Evaluation 3.9 Outbreak Control Measures, Environmental Sampling, & Reporting

4 Chapter 4: Preventing and Controlling Transmission

4.1 Standard Precautions & Hand Hygiene Guidelines 4.2 Transmission-Based Precautions & Isolation Protocols 4.3 PPE Selection, Donning, Doffing, & Safety 4.4 Safe Injection Practices & Medication Preparation 4.5 Patient-Care Equipment & Point-of-Care Device Handling 4.6 Emergency Preparedness & the Infection Preventionist's Disaster Role 4.7 Bioterrorism, Special Pathogens, & Community Response Planning

5 Chapter 5: Environment of Care

5.1 Environmental Cleaning & Surface Disinfection 5.2 Water Utilities, Air Handling, & Building Systems 5.3 Construction, Renovation, & Infection Control Risk Assessment (ICRA) 5.4 Laundry, Linen, Waste Management, & Food Safety 5.5 Product Recalls, Supply Chain Monitoring, & Device Incident Reporting

6 Chapter 6: Cleaning, Disinfection, and Sterilization of Medical Devices

6.1 Spaulding Classification System 6.2 Reprocessing Steps & High-Level Disinfection (HLD) 6.3 Sterilization Methods, Monitoring, & Quality Assurance 6.4 Single-Use Devices, Outsourced Reprocessing, & IFU Review 6.5 Reprocessing Failure Investigation & Patient Notification

7 Chapter 7: Employee and Occupational Health

7.1 Occupational Exposures & Post-Exposure Prophylaxis 7.2 Healthcare Personnel Immunizations & Screening 7.3 Work Restrictions & Fit-for-Duty Evaluations 7.4 Sharps Injury Prevention, Product Sensitivities, & Alternatives

8 Chapter 8: Management, Communication, and Antimicrobial Stewardship

8.1 IPC Program Governance, Policies, & Accreditation 8.2 Interdisciplinary Collaboration & Crisis Communication 8.3 Antimicrobial Stewardship Principles & Interventions 8.4 Chain of Command, Resource Advocacy, & the Business Case

9 Chapter 9: Education, Research, and Performance Improvement

9.1 Adult Learning Principles & Staff Education 9.2 Quality Improvement Models & Implementation Science 9.3 Critical Appraisal of Infection Prevention Literature

2.7 Host Risk Factors & Emerging Infectious Disease Threats

Key Takeaways Explain This Topic AI

Intrinsic risk factors such as age extremes, immunosuppression, diabetes, and malnutrition cannot be modified, while extrinsic factors such as devices, surgery, and antimicrobial exposure are the targets of infection prevention.

Invasive devices are the single largest modifiable driver of healthcare-associated infection, which is why device utilization ratios and daily necessity reviews sit at the center of prevention bundles.

Travel history, vaccination status, and epidemiologic exposure are essential triage elements for identifying imported measles, viral hemorrhagic fevers, avian influenza, and drug-resistant tuberculosis.

CDC's Health Alert Network, WHO Disease Outbreak News, and state and local health department advisories are the standard channels for staying informed about current and emerging threats.

Candida auris, carbapenem-resistant organisms, measles resurgence, mpox, and highly pathogenic avian influenza are the emerging threats most likely to appear in current exam scenarios.

Last updated: August 2026

2.7 Host Risk Factors & Emerging Infectious Disease Threats

Quick Answer: Intrinsic risk factors belong to the patient and cannot be changed (age, immunosuppression, diabetes, malnutrition). Extrinsic risk factors come from care delivery and can be changed (devices, surgery, antimicrobials, length of stay). Infection prevention lives almost entirely in the extrinsic column. Horizon-scanning for emerging threats runs through CDC HAN , WHO Disease Outbreak News , and state/local health department advisories .

Intrinsic Risk Factors

Factor Mechanism

Age extremes Neonates have immature immunity; older adults have immunosenescence, thinner skin, and blunted fever response

Neutropenia Absolute neutrophil count <500 cells/µL confers profound risk; <100 is critical. Drives protective environment housing for transplant patients

Immunosuppressive therapy Corticosteroids, biologics, calcineurin inhibitors, chemotherapy
Transplantation Solid organ and hematopoietic cell recipients — risk profile shifts by time since transplant
Advanced HIV CD4-dependent opportunistic infection risk

Diabetes mellitus Impaired neutrophil function, microvascular disease, poor wound healing; hyperglycemia is an independent SSI risk factor

Malnutrition / hypoalbuminemia Impaired wound healing and antibody production
Obesity Reduced tissue antibiotic penetration, larger wound surface, higher SSI risk
Burns and major skin loss Destruction of the primary mechanical barrier
Chronic organ disease COPD, cirrhosis, end-stage renal disease, heart failure
Extrinsic Risk Factors — Where Prevention Works

Factor Prevention lever
Central venous catheters Insertion bundle, chlorhexidine skin prep, daily necessity review, prompt removal
Urinary catheters Avoid placement, use alternatives, nurse-driven removal protocols
Mechanical ventilation Sedation interruption, spontaneous breathing trials, head-of-bed elevation, oral care
Surgery Prophylaxis timing, normothermia, glycemic control, appropriate hair removal (clippers, never razors)

Antimicrobial exposure Stewardship — antibiotics are the dominant risk factor for C. difficile infection and MDRO acquisition

Length of stay / ICU days Every additional day is additional exposure
Total parenteral nutrition Line dependence plus a growth-supporting infusate
Prior colonization MRSA, VRE, CRE, C. auris carriage predicts later infection

Exam Tip: When a stem asks for the most effective way to reduce a device-associated infection, the answer is almost always removing or avoiding the device , not adding a product. The device utilization ratio exists precisely to measure this exposure.

Exposure History: Travel, Vaccination, and Contact

Three questions at triage change management immediately:

Where have you been in the last 21–30 days?

What are you vaccinated against?

Who or what have you been exposed to?

Travel / exposure clue Consider Immediate IPC action

Febrile traveler from a malaria-endemic region Malaria, typhoid, dengue Standard Precautions; urgent thick/thin smears — malaria is not transmitted person-to-person

Fever + rash + coryza, unvaccinated Measles Airborne Precautions immediately ; mask the patient, AIIR, exclude susceptible staff

Fever within 21 days of travel to a viral hemorrhagic fever area Ebola, Marburg, Lassa Identify–Isolate–Inform; notify public health immediately

Poultry, dairy cattle, or wild bird contact with respiratory illness or conjunctivitis Highly pathogenic avian influenza (H5N1) Airborne + contact + eye protection; notify public health

Cough >3 weeks, weight loss, night sweats, high-incidence country of origin Tuberculosis Airborne Precautions, AIIR, three sputum specimens

Healthcare exposure abroad or transfer from an international facility CRE, C. auris , MDR organisms Pre-emptive contact precautions and admission screening

Vaccination status is itself a risk factor. Falling measles coverage has restored a pathogen with a reproduction number of 12–18 and airborne persistence for up to two hours after the patient leaves the room — the single most transmissible agent an IP is likely to encounter.

Staying Informed: The Horizon-Scanning Task

The blueprint requires candidates to stay informed about current and emerging local and global health threats . That is an operational habit with defined sources:

Source What it delivers
CDC Health Alert Network (HAN) Official U.S. advisories, alerts, and updates — subscribe directly
WHO Disease Outbreak News Verified international outbreak reports

State and local health departments Jurisdiction-specific alerts, reporting mandates, and situational awareness; usually the first notice an IP receives about local activity

CDC Emerging Infectious Diseases and MMWR Peer-reviewed and surveillance reporting
ProMED-mail Early, informal global event reporting
ECDC / PHAC European and Canadian equivalents for international facilities
Professional societies (APIC, SHEA, IDSA) Practice-oriented interpretation and guidance
Current threats worth knowing by name

Candida auris — multidrug-resistant yeast, persistent skin colonization, environmental survival, frequent misidentification on older laboratory platforms, requires sporicidal or C. auris -specific EPA List P disinfectants

Carbapenem-resistant Enterobacterales and carbapenemase-producing organisms — plasmid-mediated resistance that spreads between species

Measles — resurgent with declining vaccination coverage
Mpox — clade-dependent transmission and precaution decisions

Highly pathogenic avian influenza A(H5N1) — expanding mammalian and dairy-herd involvement with occupational exposures

Drug-resistant tuberculosis — MDR and XDR strains requiring prolonged airborne isolation
Emerging respiratory viruses — the pandemic-preparedness planning assumption

This is a One Health problem: human, animal, and environmental health are a single system, which is why avian influenza in dairy cattle becomes a hospital occupational health question.