PATHOGENS

Bloodborne pathogens are microorganisms present in human blood or OPIM that can cause disease in humans. Many are relatively rare, such as malaria, syphilis, Zika virus, and Ebola virus. Others are more common, such as the hepatitis B and C viruses, which cause inflammation of the liver, and the human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS) (OSHA, 2012).

Hepatitis B Virus (HBV)

Hepatitis B is an infection of the liver caused by the hepatitis B virus. For some people, hepatitis B is an acute or short-term illness that typically lasts for several weeks but can persist for up to six months. For others, however, hepatitis B infection can become a chronic, long-term infection. Disease is more severe among adults over the age of 60 years. 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.

The risk for chronic infection varies according to the age at time of infection and is greatest among young children. Approximately 90% of infants and 25%–50% of children aged 1–5 years will remain chronically infected with HBV. By contrast, approximately 95% of adults recover completely from HBV infection and do not become chronically infected.

In 2016, an estimated 862,000 people were living with HBV infection in the United States, and in 2018, a total of 3,322 new cases of acute hepatitis B were reported. The overall incidence rate for 2018 was 1.0 cases per 100,000 population. After adjusting for under-ascertainment (cases that do not seek healthcare) and under-reporting, an estimated 21,600 hepatitis B cases occurred in 2018. During that same year, a total of 1,649 U.S. death certificates indicated HBV as an underlying or contributing case of death; however, this is a conservative estimate (CDC, 2020a).

TRANSMISSION

HBV is transmitted through activities that involve percutaneous (i.e., puncture through the skin) 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
Birth to an infected mother
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

Hepatitis B 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, 2020a).

HBV 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.

The OSHA Bloodborne Pathogens Standard requires employers to offer the vaccination series to all workers who have occupational exposure. The vaccine and vaccination must be offered at no cost to the employee and at a reasonable time and place (OSHA, 2012).

The vaccination consists of a series of three intramuscular injections. The second injection should be given one month after the first, and the third injection six months after the initial dose. Schedules have been approved for certain vaccines and/or populations. A new formulation, Heplisav-B, 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. An employee may opt to take the vaccine at any time even after initially declining it (OSHA, 2012; CDC, 2020a).

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, 2020b).

Hepatitis C Virus (HCV)

Hepatitis C is a serious infection of the liver caused by the hepatitis C virus, a bloodborne pathogen. 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. People with chronic hepatitis C may have no symptoms, but when symptoms do appear, they are often a sign of advanced liver disease.

It is estimated that 50,300 acute hepatitis C cases occurred in 2018, and a total of 3,621 were reported to the CDC. An estimated 2.4 million people in the United States were living with hepatitis C during 2013–2016.

Because the hepatitis C virus has multiple genotypes and subtypes and mutates rapidly, there is no vaccine (CDC, 2020c).

TRANSMISSION

Hepatitis C transmission occurs mainly through parenteral exposures to infectious blood or body fluids that contain blood. Injection drug use is the most common means of transmission in the United States. Due to screening methods, hepatitis C infection rarely occurs in the United States from transfusion of donated blood, blood products, or from organ transplants. Other methods of transmission include needlesticks in healthcare settings and being born to an HCV-infected mother (CDC, 2020c).

POSTEXPOSURE MANAGEMENT

The risk of HCV transmission after percutaneous exposure is approximately 0.2% when the source patient is HCV-infected. Postexposure prophylaxis with antivirals are not currently available or approved for HCV. 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 six months.

Personnel who become infected with HCV should be referred to a healthcare provider for initiation and management of antiviral therapy and to receive interventions and education aimed at reducing liver disease progression and the prevention of HCV transmission (CDC, 2020c; NCCC, 2020).

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 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 with it, they have it 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).

There was a 7% decrease in the annual number of new HIV diagnoses from 2014 to 2018 in the United States and dependent territories. In 2018, 37,968 people received an HIV diagnosis, and an estimated 1.2 million people were living with HIV. Of these people, about 14% (1 in 7) did not know they were infected (CDC, 2020d).

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, pre-seminal 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. Only 58 cases of confirmed occupational HIV transmission to healthcare personnel and an additional 150 possible transmissions have been reported in the United States.

There is no vaccine to prevent HIV infection, but HIV prevention medications such as pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are available. The best way for healthcare workers to protect against infection is by strict adherence to Standard Precautions (CDC, 2020d).

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 and periodically for at least six months after exposure.

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. The preferred HIV occupational postexposure prophylaxis regimen is Truvada orally once a day plus Isentress (raltegravir) orally twice a day or Tivicay (dolutegravir) once a day for a duration of 28 days. A first dose of PEP should be offered while evaluation is underway and should not be delayed while awaiting information about the source person or results of the exposed worker’s baseline HIV test.

If the source person tests negative for HIV, PEP should be discontinued, and no follow-up HIV testing is clinically indicated for the exposed worker. If positive, the exposed worker should be retested for HIV at six weeks and three months (NCCC, 2020).

Ebola Virus

Ebola virus disease (EVD) (previously known as Ebola hemorrhagic fever) is a rare and deadly disease caused by a strain of the Ebola virus. EVD is often fatal if untreated. There are five identified Ebola virus species, four of which are known to cause disease in humans.

EVD was originally discovered in Africa in 1976 near the Ebola River in the Republic of Congo. The natural host of the Ebola virus is thought to be animal-borne, specifically tied to bats. Since the discovery of the Ebola virus, periodic outbreaks have occurred. In 2014, a large and serious epidemic outbreak occurred, with spread of the disease from Africa to other countries, including the United States (CDC, 2019a).

TRANSMISSION

The Ebola virus is transmitted through direct contact (broken skin or mucous membranes) with:

Blood or body fluids of a person who has Ebola or has died from Ebola (proven to be one of the most dangerous and effective methods of transmission)
Contaminated objects such as needles and syringes, medical equipment, surfaces, bedding, or clothing
Infected fruit bats or primates
Possibly from contact with semen from a man who has recovered from Ebola

The virus can remain in certain body fluids (including semen) of a patient who has recovered from EVD even if they no longer have symptoms of severe illness. There is no evidence that Ebola can be spread through sexual or other contact with vaginal fluids.

Ebola virus can survive on dry surfaces like doorknobs and countertops for several hours and in body fluids like blood for up to several days at room temperature. Ebola can remain in areas of the body where viruses and pathogens are shielded from the immune system, even after being cleared elsewhere in the body. These areas include the testes, interior of the eyes, placenta, and central nervous system, particularly the cerebrospinal fluid (CDC, 2019a).

In December of 2019, the FDA approved the vaccine rVSV-ZEBOV (Ervebo) for prevention only against the Zaire ebolavirus species of ebolavirus. The vaccine, supported by a study conducted in Guinea during the 2014–2016 outbreak, was found to be 100% effective (FDA, 2019).

POSTEXPOSURE MANAGEMENT

Asymptomatic healthcare personnel who experience unprotected exposure (not wearing recommended PPE at time of patient contact or through direct contact with blood and body fluids) to a patient with EVD should receive medical evaluation and follow-up care, including fever monitoring twice daily for 21 days after the exposure.

Healthcare personnel who develop sudden onset of signs and symptoms of EVD should seek prompt medical evaluation and testing.

Hospitals should consider policies ensuring twice-daily contact with exposed personnel to discuss potential symptoms and document fever checks (CDC, 2018).

Zika Virus

Zika virus disease is caused by the Zika virus (Aedes aegypti and Aedes albopictus), which is found worldwide. Although the illness is usually mild, Zika infection during pregnancy can cause serious birth defects such as microcephaly (smaller than normal head) as well as absent or poorly developed brain structures, defects of the eye, hearing deficits, and impaired growth. It is also associated with other complications, including preterm birth and miscarriage. Zika is also a trigger, particularly in adults and older children, of Guillain-Barré syndrome (a rare condition that can result in near to total paralysis and/or death if severe), as well as neuropathy and myelitis (WHO, 2018).

TRANSMISSION

Zika virus is primarily spread through the bites of infected Aedes species mosquitoes. Mosquitoes can become infected when they bite infected persons and can then spread the Zika virus to other persons they subsequently bite. Other modes of transmission include:

While rare, during pregnancy and through the birthing process
Sexual contact (Zika virus can stay in semen longer than in other body fluids)
Blood transfusion
Bloodborne exposure

POSTEXPOSURE MANAGEMENT

As of 2018, there have been no cases of Zika virus transmission in healthcare settings and no confirmed Zika cases from blood transfusions in the United States. There currently is no vaccine available and no specific medicine to treat Zika.

In the event of an exposure, it is recommended that the worker receive prompt and appropriate medical evaluation and follow-up, complying with OSHA’s BBP standard (CDC, 2019b).