What are blood borne and air borne diseases in occupational safety and health?

Bloodborne and Airborne Diseases in Occupational Safety and Health

In occupational health settings, bloodborne diseases are infections transmitted through contact with blood or body fluids (primarily hepatitis B, hepatitis C, and HIV), while airborne diseases are infections spread through respiratory droplets or aerosols suspended in air (primarily tuberculosis, measles, and smallpox). 1

Bloodborne Diseases

Primary Pathogens of Concern

Healthcare workers face occupational exposure to three major bloodborne pathogens that account for most transmission cases:

• Hepatitis B virus (HBV) - carries a 6-30% transmission risk after percutaneous exposure 2
• Hepatitis C virus (HCV) - carries approximately 1.8% transmission risk after percutaneous exposure 2
• Human immunodeficiency virus (HIV) - carries approximately 0.3% transmission risk after percutaneous exposure 2

Transmission Routes

Bloodborne pathogens transmit through three primary mechanisms in healthcare settings:

• Direct contact with blood, oral fluids, or other secretions 1
• Indirect contact with contaminated instruments, equipment, or environmental surfaces 1
• Percutaneous injury via hollow-bore needles with vascular access, which represents the highest proportion of occupational transmission 3

Prevention Strategies

All healthcare workers must implement universal precautions consistently for all patients, treating all blood and body fluids as potentially infectious regardless of known infection status: 1, 4

• Wear gloves whenever touching blood, body fluids, or contaminated items 1, 4
• Use protective barriers including masks and eye protection when splashing or spattering is likely 1
• Never recap needles using both hands or any technique directing the needle point toward any body part 4
• Place used sharps immediately in puncture-resistant containers located as close as feasible to the area of use 4

Vaccination Requirements

Employers must make hepatitis B vaccination available without cost to all workers who may be exposed to blood or infectious materials: 1, 5

• Healthcare workers should receive the complete 3-dose HBV vaccination series 5
• Test for anti-HBs antibodies 1-2 months after completing vaccination 1, 4
• HBV vaccination is recommended for all healthcare personnel including dentists, physicians, nurses, laboratory personnel, and custodial staff handling waste 5

Post-Exposure Management

Following occupational blood exposure, implement this immediate protocol: 1

1. Provide immediate care - wash wounds with soap and water, flush mucous membranes with water 1
2. Test the source for HBsAg, anti-HCV, and HIV antibody (consider rapid testing) 1
3. Assess the exposure severity - type of fluid and type of exposure (percutaneous, mucous membrane, or nonintact skin) 1
4. Initiate appropriate prophylaxis within 72 hours:
   • For HBV: administer vaccine and/or HBIG based on vaccination status 1
   • For HCV: no prophylaxis available, but monitor with baseline and 4-6 month anti-HCV and ALT testing 1
   • For HIV: initiate antiretroviral PEP based on exposure severity and source status 1

Airborne Diseases

Primary Pathogens of Concern

Airborne infectious diseases in healthcare settings include:

• Mycobacterium tuberculosis (tuberculosis) 1
• Measles, mumps, rubella (vaccine-preventable) 1
• Smallpox 1
• Viral hemorrhagic fever (though airborne spread not documented, prudence dictates airborne precautions) 1

Transmission Mechanism

Airborne infections transmit through contact with airborne contaminants present in either droplet spatter or aerosols of oral and respiratory fluids: 1

• Infections spread via respiratory droplets through coughing and sneezing 6
• Pathogens remain suspended in air and can be inhaled by susceptible hosts 1

Engineering Controls for Airborne Isolation

Facilities must implement specific ventilation requirements for airborne infection isolation (AII) rooms: 1

• Maintain negative pressure of at least 2.5 Pa relative to surrounding spaces 1
• Provide >12 air changes per hour (ACH) for renovated/new rooms, >6 ACH for existing rooms 1
• Direct exhaust air outside away from air intakes and populated areas, or recirculate after HEPA filtration 1
• Install self-closing devices on all AII room exit doors 1
• Monitor pressure differentials daily with visual monitoring mechanisms 1

Patient Placement Requirements

Place patients with suspected or confirmed airborne infections in appropriate isolation:

• Tuberculosis patients require AII rooms, especially during cough-inducing procedures 1
• Smallpox patients should be placed in negative pressure rooms at illness onset, preferably with an anteroom 1
• Viral hemorrhagic fever patients should be placed in AII rooms with anteroom to reduce occupational exposure risk 1

Personal Protective Equipment

Healthcare workers must use appropriate respiratory protection:

• Wear face shields or surgical masks and protective eyewear when splashing or spattering is likely 1
• Use appropriate respirators when entering rooms of patients with airborne infections 1
• Change masks between patients or during treatment if they become wet or moist 1

Common Pitfalls to Avoid

Critical errors that increase transmission risk include:

• Sharing multi-dose vials, medication containers, or IV bags between patients 4
• Inadequate hand hygiene between patients 4
• Recapping needles or bending/breaking them before disposal 4
• Failing to maintain negative pressure in airborne isolation rooms 1
• Not vaccinating healthcare workers against HBV despite mandatory employer provision 1, 5