ATrain Education

 

Continuing Education for Health Professionals

Bloodborne Pathogens: HBV, HCV, and HIV

Module 1

The Hazards of Bloodborne Pathogens

Bloodborne pathogens are infectious organisms in blood and other body fluids that can cause chronic and life-threatening disease in humans. The main bloodborne pathogens of concern are hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV), the organism that causes AIDS.

The Science

Hepatitis B

Recent investigations of viral hepatitis outbreaks in the United States demonstrate the continued risk posed by lapses in infection-control practices, particularly in healthcare settings (Thompson et al., 2009).

HBV is transmitted by percutaneous or mucosal exposure to the blood or body fluids of an infected person, most often through injection-drug use, from sexual contact with an infected person, or from an infected mother to her newborn during childbirth. Transmission of HBV also can occur among people who have prolonged but nonsexual interpersonal contact with someone who is HBV-infected (eg, healthcare workers) (CDC, 2010).

Infection may be acute and later cleared or it may become chronic, carried for a prolonged period or for life. Infection may be completely free of symptoms, produce mild or moderate illness, or be rapidly fatal. Most people who are chronically infected are without symptoms.

Serious complications (eg, cirrhosis, liver cancer) are more likely to develop in chronically infected people. In the United States, approximately 1.2 million people have chronic HBV infection and are sources for HBV transmission to others; however, since the 1980s the incidence of acute hepatitis B has declined steadily, especially among vaccinated children (CDC, 2011).

 

chart: incidence of hepatitis B, by year, US, 1980-2011

Source: CDC: 2011.

Effective hepatitis B vaccines have been available in the United States since 1981. In addition to hepatitis B vaccination, efforts have been made to improve care and treatment for people living with hepatitis B. In the United States, 804,000 to 1.4 million people are estimated to be infected with the virus, most of whom are unaware of their infection status (CDC, 2008).

To improve health outcomes for these people, CDC issued recommendations in 2008 to guide hepatitis B testing and public health management of people with chronic hepatitis B infection. These guidelines stress the need for testing people at high risk for infection, conducting contact management, educating patients, and administering FDA-approved therapies for treating hepatitis B (CDC, 2008).

Since publication of the 2008 recommendations, treatment options for HBV infection have expanded. Several drugs are now administered orally (a major advancement in how treatments are administered for this infection), leading to viral suppression in 90% of patients taking one of these new oral medications.

The risk of transmission of HBV following a positive needlestick varies from 6% to 30%, depending on the degree of infectivity of the source individual. Healthcare workers who have received hepatitis B vaccine and have developed immunity to the virus are at virtually no risk for infection.

For an unvaccinated person, the risk from a single needlestick or a cut exposure to HBV-infected blood ranges from 6% to 30% and depends on the hepatitis B e-antigen (HBeAg) status of the source individual. Individuals who are both hepatitis B surface antigen (HBsAg)-positive and HBeAg-positive have more virus in their blood and are more likely to transmit HBV (CDC, 2013b).

Hepatitis C

[This section taken largely from CDC, 2013b.]

Hepatitis C virus (HCV) is transmitted primarily through percutaneous exposure, most commonly by injection-drug use. People newly infected with HCV are usually asymptomatic, so acute hepatitis C is rarely identified or reported. With an estimated 3.2 million chronically infected people nationwide, HCV infection is the most common bloodborne infection in the United States.

HCV infection becomes chronic in approximately 75% to 85% of cases. Chronic HCV infection is the leading indication for liver transplants in the United States. Most people with chronic HCV infection are asymptomatic; however, many have chronic liver disease, which can range from mild to severe, including cirrhosis and liver cancer. Chronic liver disease in HCV-infected people is usually insidious, progressing slowly without any signs or symptoms for several decades.

Based on limited studies, the estimated risk for infection after a needlestick or cut exposure to HCV-infected blood is approximately 1.8%, or 1 in 50. The risk following a blood splash to mucous membranes is unknown but is believed to be very small; however, HCV infection from such an exposure has been reported.

There is no vaccine or post exposure prophylaxis against HCV. Prevention of exposure is the only protection against it.

HIV

Human immunodeficiency virus (HIV) is the virus that causes AIDS (acquired immune deficiency syndrome, first identified in 1981). Many years may pass between the time of infection before symptoms of illness begin or are identified. Individuals who have the virus but are not yet sick have no symptoms and many do not know that they are infected. Medications can slow the course of the disease, and there are medications that can be taken after exposure to reduce the likelihood of infection (PEP).

 

chart: Rates of Adults and Adolescents with Diagnosed HIV, US, 2010

Source: CDC, n.d.

The average risk for HIV infection after a needlestick or cut exposure to HlV-infected blood is 0.3% (about 1 in 300). Stated another way, 99.7% of needlestick/cut exposures to HIV-contaminated blood do not lead to infection. The risk after exposure of the eye, nose, or mouth to HIV-infected blood is estimated to average 1 in 1000 (CDC, 2013b). These are encouraging statistics—unless you are the one. The risk is low but it is not zero.

Who Is At Risk?

It is not at all rare for people to carry more than one of the three viruses just discussed, since these pathogens are spread by similar routes: blood-to-blood contact, sexual contact, and injecting-drug use.

In addition to hepatitis B, hepatitis C, and HIV, other less-common bloodborne pathogens include:

  • Hepatitis delta (HDV)
  • Malaria
  • Syphilis
  • Babesiosis
  • Brucellosis
  • Leptospirosis
  • Arboviral infections
  • Relapsing fever
  • Creutzfeldt-Jakob disease
  • Adult T-cell leukemia/lymphoma (caused by HTLV-I)
  • HTLV-I-associated myelopathy
  • Diseases associated with HTLV-II
  • Viral hemorrhagic fever (OSHA, 2011a)

Some of the listed diseases are extremely rare in the United States; however, today’s mobility of individuals and families means that rare diseases can travel globally. Healthcare workers need to be aware of their possible risk of exposure to rare diseases as well as those common to their own country.

The most important thing to remember about all three of the main viruses is that most people infected with them are asymptomatic. This is why it is critical to avoid contact with the blood and body fluids of all individuals, since there is no easy way to tell those infected from those who are not.

Those who are at risk include:

  • People who have contact with blood or body fluids in their personal lives, whether through sexual activity, by injected drug use, or by other mechanisms.
  • Patients who may have exposure to the blood or body fluids of caregivers by unintended means
  • People who have contact with blood or body fluids in their work life (occupational exposure)

 

Source: CDC, 2013.

Chronic Infectious Diseases in the United States, 2009

Disease

People infected
(estimated)

Annual new infections

HIV/AIDS

1.1 million

50,000

Hepatitis B

1.4 million

33,000 estimated

Hepatitis C

3.2 million

17,000 estimated

Science related to bloodborne pathogens is reliably available from the Centers for Disease Control website. To reach their website specific to bloodborne pathogens issues, click here.

The Law

OSHA Bloodborne Pathogens Standard

Law regarding bloodborne pathogens is based on the federal OSHA Bloodborne Pathogens Standard, 29 CFR 1910-1030, originally passed into law in 1992 and amended in 2001. All the requirements of the Bloodborne Pathogens Standard are designed to protect workers from exposure to bloodborne pathogens (OSHA, 2013a).

State Laws

State legislation has been enacted in twenty-two states to improve healthcare worker safety related to needle sticks. These laws add provisions not included in the federal OSHA Bloodborne Pathogen standard and/or coverage of public employees not regulated by OSHA. These laws contain unique requirements such as surveillance programs, cost-benefit analyses, strict requirements for safety device use, and the use of statewide advisory boards.

Implementation of state laws differs regarding development of related regulations and dates when they become effective. State-by-state provisions are available online (OSHA, 2011b). Some resources for state laws are listed in the References.

Compliance with the federal law and any applicable state law is required of all workplace settings where healthcare workers may be exposed to blood or body fluids on the job.

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