PATHOGENS

Bloodborne pathogens are microorganisms present in human blood or other potentially infectious material (OPIM) that can cause disease in humans. Many are relatively rare, but of those bloodborne pathogens known to cause diseases, there are three diseases specifically addressed by the Bloodborne Pathogens Standard that are the most common pathogens of concern in the work place—hepatitis B and hepatitis C viruses, which cause inflammation of the liver, and the human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS). These three account for the majority of occupationally acquired infections associated with significant morbidity and mortality (Denault & Garner, 2023).

Hepatitis B Virus (HBV)

Hepatitis B is an infection of the liver caused by the hepatitis B virus. Acute hepatitis is a short-term illness that occurs within the first six months following exposure. Some people with acute hepatitis B have no symptoms at all or only a mild illness. For others, acute hepatitis causes more severe illness and requires hospitalization.

Approximately 25% of those who become chronically infected by HBV during childhood and 15% of those after childhood die prematurely from cirrhosis or liver cancer, and most remain asymptomatic until onset of cirrhosis or end-stage liver disease.

In 2020, a total of 2,157 cases of acute hepatitis B were reported to the CDC, for an overall incidence rate of 0.7 per 100,000 population. After adjusting for under-reporting by healthcare providers and under-ascertainment (those not seeking healthcare), there are an estimated 580,000 to 1.17 million people with HBV infection in the United States, two thirds of whom may be unaware of their infection. During that same year, a total of 1,752 hepatitis-B-associated deaths among U.S. residents were reported, corresponding to a death rate of 0.45 cases per 100,000 population (CDC, 2023a).

TRANSMISSION

HBV is transmitted through activities that involve percutaneous or mucosal contact with infectious blood or body fluids (e.g., semen or saliva), including:

• Sex with an infected partner
• Injection drug use that involves sharing needles, syringes, or drug-preparation equipment
• Mother-to-baby during pregnancy or delivery
• Contact with blood or open sores of an infected person
• Needlesticks or sharp instrument exposures
• Sharing items that can break the skin or mucous membranes (such as razors, toothbrushes, or medical equipment [e.g., glucose monitor]) with an infected person
• Poor infection control practices in healthcare settings

HBV is not transmitted through:

• Breastfeeding
• Sharing eating utensils
• Hugging, kissing, holding hands
• Coughing or sneezing
• Contaminated food or water (unlike some other forms of hepatitis)

HBV is very resilient and can survive outside the body at least seven days and still be capable of causing infection. For this reason, the virus is a concern for medical personnel such as nurses, laboratory technicians, and paramedics, as well as custodians, laundry personnel, and other employees who may come in contact with blood or other potentially infectious materials (CDC, 2023a).

HEPATITIS B VACCINE

The hepatitis B vaccine is the best protection from the disease. All employees who may possibly be exposed to blood or other potentially infectious materials as part of their job duties are eligible to be vaccinated against HBV.

As described above, the OSHA Bloodborne Pathogens Standard 1910.1030(f)(1)(i) states that employers shall make available the hepatitis B vaccine and vaccination series to all employees who have occupational exposure and postexposure evaluation and follow-up to all employees who have had a recent exposure incident. The vaccine and vaccination must be offered at no cost to the employee and at a reasonable time and place (OSHA, 2019).

Hepatitis B vaccines available in the United States include:

• Engerix-B
• Recombivax HB
• Heplisav-B
• Prehevbrio (13)

Three intramuscular injections are required for the first three vaccines at one and six months after the first dose. Heplisav-B, however, is approved for two doses, one month apart.

To ensure immunity, it is important to receive all recommended injections. The vaccine causes no harm to those who are already immune or to those who may be HBV carriers.

Although employees may opt to have their blood tested for antibodies to determine the need for the vaccine, their employers may not make such screening a condition of receiving vaccination, nor are employers required to provide screening.

Employees who decide to decline vaccination must complete a mandatory declination form, the purpose being to encourage greater participation in the vaccination program by stating that the worker declining the vaccination remains at risk of acquiring hepatitis B. An employee may opt to take the vaccine at any time even after initially declining it (OSHA, 2019; CDC, 2023a).

POSTEXPOSURE MANAGEMENT

Following an exposure to HBV, prophylaxis can prevent HBV infection and subsequent development of chronic liver infection. The central component of postexposure prophylaxis is hepatitis B vaccine, which provides long-term protection. The vaccine series should be started as soon as possible after exposure, preferably within 24 hours. In certain circumstances, hepatitis B immune globulin is recommended in addition to vaccine to provide short-term passive immunity (CDC, 2020a).

Hepatitis C Virus (HCV)

HCV is a serious infection of the liver caused by the bloodborne hepatitis C virus. For some people, hepatitis C is a short-term illness, but for more than 50% of those who become infected, it becomes a long-term, chronic infection that can result in serious, even life-threatening, health problems such as cirrhosis and liver cancer. Approximately 5%–25% of people with chronic hepatitis C develop cirrhosis over 10 to 20 years. People with chronic hepatitis C may have no symptoms, but when symptoms do appear, they are often a sign of advanced liver disease. People with hepatitis C and cirrhosis have a 1%–4% annual risk for hepatocellular carcinoma.

In 2020 there were an estimated 66l,700 reported cases of hepatitis C infection in the United States, and 41 states reported a total of 107,300 newly identified chronic hepatitis C cases and 40.7 newly reported cases of chronic hepatitis C per 100,000 people. The incidence rate of acute hepatitis C has more than doubled since 2013 and increased 15% from 2019, primarily resulting from the ongoing opioid epidemic and associated injection drug use.

Because the hepatitis C virus has multiple genotypes and subtypes and mutates rapidly, there is no vaccine (CDC, 2023a; Spach, 2021).

TRANSMISSION

HCV transmission occurs mainly through parenteral exposures to infectious blood or body fluids that contain blood. Mucous membrane exposures to blood can also result in transmission, although less efficiently. HCV is transmitted primarily through sharing contaminated needles, syringes, or other equipment used to inject drugs.

HCV is less commonly transmitted through:

• Birth to an infected pregnant person
• Sexual contact with an infected person
• Unregulated tattooing or piercing
• Needlesticks or other sharp instrument injuries
  (CDC, 2023a)

POSTEXPOSURE MANAGEMENT

The risk of HCV transmission after percutaneous exposure is approximately 0.2% when the source patient is HCV infected. Following exposure, initial management includes baseline testing of the source patient and the healthcare worker as soon as possible (preferably within 48 hours) after exposure, with initial follow-up in six weeks and final follow-up in 4–6 months.

Testing for HCV is based on the following sequence: Most persons who acquire HCV infection will have a positive HCV RNA within 1–2 weeks of exposure, and antibodies to HCV generally appear 8–11 weeks after exposure.

If the source patient is HCV-RNA-positive or source-patient testing is not performed or not available, baseline testing should be followed by a nucleic acid test (NAT) for HCV RNA at 3–6 weeks post exposure This test also should be performed if a source patient is anti-HCV-positive and no source patient HCV RNA is available.

Postexposure therapy with direct-acting antiviral agents (DAA) is not routinely recommended, as percutaneous and mucocutaneous exposure risks are low and in most situations do not justify giving these medications because of potential side effects.

Healthcare personnel with detectable HCV RNA or anti-HCV seroconversion as a result of an occupational exposure should be referred for further care and evaluation for treatment. DAA therapy is highly efficacious, and new HCV infections should be identified early and treated (CDC, 2023a; NCCC, 2021).

Human Immunodeficiency Virus (HIV)

HIV has existed in the United States since at least the mid- to late-1970s. The virus spreads via blood and other body fluids and attacks the body’s immune system, specifically the CD4⁺ T cells. Untreated HIV infection reduces the number of T cells in the body, which makes it more and more difficult for the body to fight off infections and other diseases. There currently is no effective cure for HIV infection, and once an individual becomes infected, they are infected for life. Opportunistic infections or cancers take advantage of a very weak immune system and are signs that a person has AIDS (acquired immunodeficiency syndrome).

In 2021, 36,136 people received an HIV diagnosis in the United States and dependent areas. The annual number of new diagnoses decreased 7% from 2017 to 2021, and at that time, there were an estimated 1.2 million people in the United States living with HIV. Of these people, 87% knew they were infected (CDC, 2022b).

TRANSMISSION

HIV is transmitted most commonly in the United States through sexual behaviors and sharing of needles, syringes, or equipment used to prepare drugs for injection. Only certain body fluids (blood, semen, preseminal fluid, rectal fluids, vaginal fluids, and breast milk) from a person who is infected can transmit HIV. These fluids must come in contact with a mucous membrane or damaged tissue or be directly injected into the bloodstream for transmission to occur.

For healthcare workers, the risk of occupational exposure is very low. The main risk is from being stuck with an HIV-contaminated needle or other sharp object. This risk, however, is small and estimated to be less than 1%. HIV contamination has also been reported by healthcare workers from body fluid splashes to the eye, the risk of which is near zero.

There is no vaccine to prevent HIV infection, but HIV prevention medications such as pre-exposure prophylaxis (PrEP) and postexposure prophylaxis (PEP) are available. The best way for healthcare workers to protect against infection is by strict adherence to Standard Precautions (CDC, 2022b).

POSTEXPOSURE MANAGEMENT

Occupational exposures require urgent medical evaluation. Baseline HIV testing of the source patient and the exposed worker should be done as soon as possible.

PEP should be initiated as soon as possible within a maximum of 72 hours after a recent possible exposure to HIV, but the earlier PEP is started, the better. If additional information subsequently becomes available that the source person is HIV negative, PEP can always be discontinued.

Three-drug PEP regimens are now the recommended management for all exposures. There are some special circumstances in which a two-drug regimen can be considered or used, especially when recommended antiretroviral medications are unavailable or there is a concern about potential toxicity or adherence difficulties.

The preferred three-drug HIV PEP regimen includes Truvada, which is a two-drug combination of emtricitabine (FTC) and tenofovir disoproxil fumarate, one tablet orally once daily, plus either raltegravir (Isentress) 400 mg orally twice daily or dolutegravir (Dovato) 50 mg orally once daily. This regimen is continued for a 28-day duration.

If the source person tests negative for HIV, PEP is discontinued, and no follow-up HIV testing is clinically indicated for the exposed worker. If the source person tests positive, the exposed worker is retested for HIV at six weeks and three months (NCCC, 2021).