What is a common transmission route for bloodborne pathogens?

Bloodborne pathogens are microorganisms in human blood that can cause life-threatening diseases and pose a severe risk to health care workers. Contact with blood or other fluids, including semen, vaginal secretions, saliva, and serous fluids – pleural, pericardial, peritoneal, and amniotic – clear or visibly contaminated with blood potential to transmit the pathogen and cause infectious disease. In the health care setting, bloodborne pathogens are often transmitted by percutaneous injury, accidental puncture, human bites, cuts, abrasions, or through mucocutaneous exposure to infected patient’s fluids. In the workplace, the major source of bloodborne infections is percutaneous injuries from needles or other sharps. Especially prone to exposure are medical professions involving frequent invasive procedures, a high volume of blood, and urgency of care. Health care workers in surgery, emergency medicine, critical care, labor and delivery, and dialysis units are most prone to occupational exposure. Other occupations with exposure risk include mortuary and funeral services, hospital maintenance, and waste removal workers.

Of the 20 bloodborne pathogens known to cause diseases such as malaria, syphilis, and hemorrhagic fever, there are three; hepatitis B (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) that are the most common pathogens of concern. These three viruses account for the majority of occupationally-acquired infections and are associated with significant morbidity and mortality. Although the vast majority of occupational exposures do not manifest in disease, the overall risk of the transmission is variably dependent on several factors, including the type and size of the inoculum, duration of exposure, a titer of the virus, and the prevalence of the active infection in the population.

Hepatitis B is a viral infection capable of causing persistent, chronic infection that can lead to acute and chronic disease. It is a hepatotropic virus transmitted via blood or semen from infected individuals to those lacking immunity. HBV is a global health problem and a well-established occupational risk for health care workers. The incidence of HBV in the population is steadily rising, and the prevalence of HBV infection in health care workers is much greater than in the general population. The virus is structurally stable, remaining viable and infectious for prolonged periods of up to 1 week on surfaces. HBV is highly infectious and efficiently transmitted through percutaneous or mucosal exposure to infectious blood or body fluids. The risk of percutaneous HBV infection varies from 6 to 30%, depending on the serology of the source. Vaccines to prevent HBV became available in 1981 and remained the mainstay of hepatitis B prevention. Among the safety measures listed, the Bloodborne Pathogens Standard mandates that employers ensure this vaccine's availability to all employees at risk for occupational exposure.

Hepatitis C, another hepatotropic virus, is the most commonly reported bloodborne infection in the United States and a serious public health problem. HCV is primarily transmitted via parenteral exposure, most commonly contaminated needles. The prevalence of HCV among health care workers does not exceed that of the general population; however, there is an increased risk of exposure in the health care setting. The risk of transmission when exposed to HCV-positive blood is 1.8%, considerably lower than HBV. Treatments are evolving with the development of new, targeted therapies. Currently, there is no vaccine or post-exposure prophylaxis (PEP) for HCV infection.

The human immunodeficiency virus (HIV) targets the immune system causing acquired immunodeficiency syndrome (AIDS). HIV is transmitted via direct contact with blood, semen, rectal fluids, vaginal fluids, or breast milk from an individual with a detectable viral load. In the workplace, occupational transmission is influenced by several factors, including volume of blood, type of procedure, type of injury, or percutaneous penetration. Compared to HBV and HCV, the percutaneous risk of HIV transmission is the smallest, estimated to be around 0.3%. While there is no cure for the disease, there are antiviral medications that slow the progression. In cases of exposure, if taken within 72 hrs, administration of post-exposure prophylactic (PEP) medications are highly effective in preventing HIV.

Collectively, bloodborne pathogens are a threat to human lives and remain a public health problem. It is estimated that approximately three million exposures to bloodborne pathogens occur annually. In most work or laboratory settings, bloodborne infections are often due to accidental punctures. In the United States, there are an estimated 400,000 sharp injuries per year in the hospital setting.

In 1991, the Occupational Safety and Health Administration (OSHA) issued the Bloodborne Pathogens Standard in response to the global concern. This standard ensures the safety of health care workers at risk for occupational exposure. The regulations prescribed to employers are located in Title 29 of the Code of Federal Regulations at 29 CFR 1910.1030. Strict adherence to these regulations and guidelines will reduce the risk, minimize exposure, and help prevent bloodborne pathogens' transmission. Specifically, the federal standard mandates employers do the following:

1. Establish and annually update an exposure control plan.

2. Provide initial and annual education and training to workers.

3. Make available hepatitis B vaccination series within 10 days of the employee’s assignment.

4. Implement the use of universal precautions.

5. Identify and use approved engineering controls.

6. Identify and ensure the use of work practice controls.

7. Use of warning labels and/or signs to communicate hazards.

8. Provide adequate and appropriate personal protective equipment (PPE) for employees.

9. Establish readily available post-exposure evaluation and follow-up plans.

10. Maintain employee medical and training records.

Since the highest proportion of bloodborne pathogens' occupational transmission was due to percutaneous injury, in 2000, the standard was revised to include the Needlestick Safety and Prevention Act (HR.5178). As the name suggests, this revision imposed additional requirements for employees with greater detail concerning their sharps protocol. Specifically, it requires employers to consider and implement new technologies and use effective and safer medical devices. When considering newer technologies, employers are required to solicit employee input. Lastly, employers are required to maintain a sharps injury log. Promotion of the use of safe needles or needleless devices, and other interventions, has resulted in a significant decline in percutaneous injuries among health care workers in U.S. hospitals.

In addition to the federal standard, some states enacted additional laws to improve healthcare worker safety. These OSHA-approved and monitored state plans contain more stringent requirements than the federal standard and add unique provisions not included in the original standard. The state plans are more stringent than the federal standard, and at the very least, as effective in the protection and prevention of health care workers from occupational injuries, illnesses, and deaths. Each state law varies in terms of its time frame for development, coverage, and scope. Health care workers should consult their own state and local regulatory agencies to complete the provisions and regulations.

Exposure Control Plan

Prevention is the lynchpin of the Bloodborne Pathogens Standard and begins with developing an exposure control plan. Employers must develop and implement an exposure control plan that identifies and lists all job classifications and tasks for those who reasonably anticipate contact with blood or other potentially infectious materials as part of their duties. The plan must outline a schedule of standard implementation, review of engineering controls, and document annually consideration of safer medical devices specifically designed to reduce occupational exposures. Employers must seek and document input from non-managerial staff on the consideration, implementation, and effectiveness of newer engineering devices. The plan should also include employees trained to administer first aid to an injured employee if necessary.

Training

Training must be offered at no cost to each health care worker with the risk of occupational exposure before their first assignment and on an annual basis thereafter. Training elements include the following:

1. General information about the epidemiology of bloodborne pathogens and the manifestation of disease

2. Modes and risks of transmission of the bloodborne pathogens.

3. Information on the Hepatitis B vaccine series.

4. Explanation of the employer’s exposure control plan

5. Explanation of methods for recognizing high-risk exposure tasks Explanation of the use and limitations of methods to reduce exposure, including engineering controls, work practice controls, and the proper use and selection of PPE.

6. Information on the removal, handling, decontamination, and disposal of PPE

7. Incident reporting protocols.

8. Post-exposure protocols including medical evaluation contact information and follow-up procedures.

Training materials must be readily available to workers, including access to a copy of OSHA’s Bloodborne Pathogens Standard and information on how and where to access the exposure control plan. The training must be conducted by a knowledgeable person, delivered at an appropriate and understandable educational level and language. The trainer must provide sufficient time for an interactive question and answer session with the trainees.

Hepatitis B Vaccine

The Bloodborne Pathogens Standard mandates employers to make the hepatitis B vaccination series available to the worker, at no cost, within 10 days of the employee’s assignment and after the required bloodborne pathogens training. The vaccination series, usually given as three or four shots over a six-month period, must be offered to the worker at a reasonable time and place. Employees have the right to decline the vaccination but must sign a declination form indicating such.

Universal Precautions

OSHA’s bloodborne standard for reducing exposure risk and infection control is grounded on the adoption of Universal Precautions. Universal Precautions assumes that all body fluids (blood, saliva, secretions) and sites (open wounds and mucous membranes) contain pathogenic microorganisms, such as HBV, HCV, and HIV potentially infectious. Employees that observe Universal Precautions will treat all potentially infectious materials with appropriate precautions such as hand hygiene, the use of personal protective equipment (PPE), and engineering and work practice controls to limit exposure.

Engineering and Work Practice Controls

Engineering controls are devices and tools designed to isolate and remove contaminated equipment from the workplace. Work practice controls are alterations in how a workplace task is completed to reduce the likelihood of exposure. When combined, these controls effectively eliminate or reduce the risk of exposure and transmission of infectious disease. Examples include handwashing facilities or antiseptic hand cleanser, proper use of personal protective equipment (PPE), needle safety devices, puncture-resistant, closeable, and leakproof sharp containers, and the proper handling, storage, and disposal of potentially hazardous materials.

PPE protects employees from exposure by creating a barrier against bloodborne pathogens. Employers must conduct a risk assessment of the worksite hazards, identify potential exposures and assign PPE accordingly. Basic PPE, including fitted gloves, masks, and gowns, should be readily available and worn whenever there is potential for contact with bodily fluids and contaminated equipment. PPE does not eliminate the hazard, and proper fit is critically important. For example, the surgical gown must provide adequate coverage in the critical primary protection zones. PPE that is too large or loose may minimize tactile sensitivity and has the potential to be a hazard. Properly fitted PPE has greater user satisfaction and is, therefore, more likely to be consistently worn. In addition to basic equipment, for procedures posing an additional exposure risk such as wound irrigation, additional protective equipment such as a face shield will provide a barrier to the back spray and should be readily available. Employers are responsible for the risk assessment, accessibility, proper use, cleaning, disposal, repair, and replacement of PPE.

Since the bloodborne pathogens standard was published, many different engineering controls and medical devices have been developed to reduce exposure risk. For example, contaminated PPE and equipment should be placed in appropriately labeled bags or containers for safe disposal. A warning label that includes the universal biohazard symbol must be displayed and readily observable on all bags and containers with contaminated items. The availability and use of engineering controls, including sharps disposal containers and self-sheathing needles, for removing contaminated pathogens is another important step in the safe removal of hazardous waste.

Along with PPE, proper hand hygiene is one of the most effective means of infection control and preventing disease transmission. All employees caring for patients must perform hand hygiene. Current CDC guidelines recommend using alcohol-based hand rub with at least 60% alcohol (60% ethanol or 70% isopropyl alcohol) or handwashing with soap and water for at least 20 seconds before and after touching a patient or performing an aseptic procedure. Hand hygiene should also be practiced when moving from a soiled to a clean body site, after touching a patient, contacting blood, body fluids, contaminated surfaces. Proper hand hygiene is necessary immediately before donning and immediately after doffing PPE.

Post-exposure Evaluation

Immediately after the exposure, the health care worker should be evaluated and first aid administered. First aid is site and injury-dependent. Wounds and skin injuries involving needle sticks or cuts in contact with blood or body fluids should be washed with soap water. Mucous membranes, such as the nose or mouth, should be flushed with water. If the exposure was to the eye, they should be irrigated with clean water, saline, or sterile irrigants.

Exposure to bloodborne pathogens should be promptly reported to the employer, such as the direct supervisor or department responsible for managing occupational health. Careful evaluation of the exposure and exposure source should be done. Medical evaluation of the employee must take place immediately because some treatment decisions, including chemoprophylaxis, must be made within 2 hours of exposure. Follow-up evaluations should occur at an occupational clinic in one week, three months, six months, and twelve months depending on the exposure type and source. During these visits, the health care worker's health status is evaluated, and, depending on the infection, repeat testing may be necessary. A careful record of the specific circumstances and postexposure management plan must be included in the employee's confidential medical record.