Occupational Safety and Health: Airborne and Bloodborne Infections in Primary Healthcare
Overview of Transmission Risks
Primary healthcare workers face dual infectious hazards from both airborne pathogens (particularly Mycobacterium tuberculosis) and bloodborne pathogens (hepatitis B virus, hepatitis C virus, and HIV), requiring distinct but complementary prevention strategies. The risk of occupational transmission varies significantly by pathogen: hepatitis B carries a 6-30% transmission risk after percutaneous exposure, hepatitis C approximately 1.8%, and HIV approximately 0.3% 1. Airborne transmission of tuberculosis represents a recognized occupational hazard, particularly in settings serving populations with high TB prevalence or HIV-infected patients 2.
Fundamental Prevention Principles
Universal Precautions for Bloodborne Pathogens
The cornerstone of bloodborne pathogen prevention requires treating all blood and body fluids as potentially infectious, regardless of a patient's known infection status 3, 2. Healthcare workers must wear gloves whenever touching blood, body fluids, or contaminated items, and use protective barriers including masks and eye protection when exposure is anticipated 3, 1. Never recap used needles using both hands or any technique directing the needle point toward any body part, and place used sharps immediately in puncture-resistant containers located at the point of use 3.
Airborne Infection Control Hierarchy
Prevention of airborne transmission requires a multi-layered approach: early identification and isolation of infectious patients, engineering controls for ventilation, and respiratory protection for healthcare workers 2. The most critical intervention is early recognition and isolation of patients with suspected tuberculosis before they contaminate general healthcare areas 2.
Engineering and Environmental Controls
Ventilation Requirements for Airborne Isolation
Airborne infection isolation (AII) rooms must maintain continuous negative air pressure of 2.5 Pa relative to corridors, monitored daily with audible manometers or visual monitoring systems 2. Renovated and new AII rooms require greater than 12 air changes per hour (ACH), while existing rooms require at least 6 ACH 2. Exhaust air must be directed outside away from air intakes and populated areas, or recirculated only after HEPA filtration 2.
Supplemental Air Cleaning Methods
Where risk assessment indicates need for enhanced protection, install UVGI (ultraviolet germicidal irradiation) units in exhaust ducts to supplement HEPA filtration, or install UVGI fixtures near ceilings for upper-room air irradiation 2. Portable industrial-grade HEPA filters can provide additional air cleaning in rooms without adequate fixed ventilation 2.
Administrative Controls and Screening
Healthcare Worker Surveillance
All healthcare workers with potential occupational exposure to blood must be offered hepatitis B vaccination series, with antibody testing 1-2 months after completing the three-dose series 3. Workers should receive baseline tuberculin skin testing (Mantoux test) at employment, with frequency of repeat testing determined by facility risk assessment 2. Those with positive tuberculin tests require evaluation for active disease and consideration of preventive therapy 2.
Patient Screening and Early Identification
Tuberculosis must be included in the differential diagnosis for any patient presenting with pulmonary signs or symptoms 2. For patients whose pulmonary symptoms are initially attributed to other causes, repeat evaluation for tuberculosis is mandatory if the patient fails to respond to appropriate therapy for the presumed diagnosis 2. Rapid diagnostic services and prompt initiation of appropriate isolation and treatment are essential 2.
Personal Protective Equipment
Respiratory Protection
Healthcare workers entering rooms of patients with confirmed or suspected tuberculosis must wear N95 respirators approved by NIOSH 2. Respirators without exhalation valves should be used in operating rooms when infectious TB patients require emergency surgery 2. Fit testing is required to ensure proper seal and protection 2.
Barrier Protection for Bloodborne Pathogens
Gloves must be worn whenever touching patients or equipment in high-risk settings such as hemodialysis units 3. Face shields or goggles with appropriate respirators are required when entering rooms of patients with viral hemorrhagic fever who have prominent cough, vomiting, diarrhea, or hemorrhage 2.
Safe Injection Practices
Needle and Syringe Management
Never reuse or share syringes, needles, or drug-preparation equipment between patients, and medications must not be shared among patients 3. Implement engineering controls including safer devices with built-in safety features, evaluating and selecting such devices at least annually 3. Clean injection sites with new alcohol swabs before each injection 3.
Equipment Sterilization
The use of improperly sterilized medical or dental equipment represents a significant transmission risk for bloodborne pathogens 4. All reusable equipment must undergo appropriate high-level disinfection or sterilization between patients 2.
Special Considerations for High-Risk Procedures
Cough-Inducing Procedures
Patients requiring cough-inducing procedures such as sputum induction or aerosolized pentamidine treatments must be placed in AII rooms or enclosed booths engineered to provide greater than 12 ACH, maintain 2.5 Pa negative pressure, and exhaust air directly outside or through HEPA filtration 2. These procedures should never be performed in general treatment areas 2.
Hemodialysis Settings
In hemodialysis centers, gloves must be worn whenever patients or equipment are touched, and specific dialysis stations should be assigned to patients with chairs and beds cleaned after each use 3. Strict adherence to water quality standards and equipment maintenance protocols is essential 2.
Post-Exposure Management
Immediate Response Protocols
Establish written protocols for reporting and follow-up of percutaneous or mucosal exposures to blood or body fluids 3, 1. Following occupational exposure with potential for HIV transmission, antiretroviral post-exposure prophylaxis must be evaluated and initiated as soon as possible, ideally within hours 1, 5.
Bloodborne Pathogen Exposures
For non-vaccinated healthcare workers exposed to HBsAg-positive or untested source patients, post-exposure prophylaxis with HBV vaccine, hepatitis B immunoglobulin, or both must be started immediately 5. Although no prophylaxis exists for hepatitis C, early identification and treatment of transmission is crucial 5.
Common Pitfalls and How to Avoid Them
Using multiple-use nozzle jet injectors without proper cleaning between patients dramatically increases transmission risk and should be avoided 3. Sharing multi-dose vials, medication containers, or IV bags between patients is never recommended 3. Inadequate hand hygiene between patients remains a persistent problem; strict adherence to hand hygiene protocols is non-negotiable 3, 2.
The most critical error in airborne infection control is failure to maintain proper air pressure differentials in isolation rooms 2. Daily monitoring with visible indicators prevents this failure. Another common mistake is performing cough-inducing procedures in inadequately ventilated areas 2.
Facility-Level Responsibilities
Healthcare facilities must designate specific personnel responsible for infection control programs and maintain written TB infection-control plans reviewed at least every 7 years or when epidemiology changes 2. Facilities should include engineers or consultants with ventilation expertise working closely with infection-control committees 2. Direction of air flow must be established so air moves from clean areas to less-clean areas, with periodic verification using smoke tubes 2.
Ongoing training and education regarding infection-control practices must be provided for all healthcare workers 2. Facilities serving populations with high TB prevalence may need enhanced ventilation in waiting areas, emergency rooms, and treatment rooms where infectious patients are likely to be encountered 2.