A bloodborne pathogen (BBP) is a microorganism found in human blood that can cause disease in humans. These infectious agents are primarily transmitted through contact with contaminated blood or certain other body fluids. The three pathogens that represent the greatest health concern due to their prevalence and potential for serious, long-term illness are the Hepatitis B Virus (HBV), the Hepatitis C Virus (HCV), and the Human Immunodeficiency Virus (HIV).
Hepatitis B Virus (HBV): Characteristics and Risk
The Hepatitis B Virus specifically targets and replicates within the cells of the liver, causing inflammation that can lead to significant damage. An infection can manifest as either an acute or a chronic, lifelong condition. Most healthy adults who contract the virus experience an acute infection and clear the virus completely, with about 90% recovering fully within six months.
The risk of developing chronic HBV infection is strongly related to the age at which a person is first exposed. More than 90% of infants infected at birth will develop a chronic infection. The persistence of the virus leads to a higher risk of developing serious long-term complications, including cirrhosis (scarring of the liver) and hepatocellular carcinoma (liver cancer).
A highly effective vaccine is available for HBV. The vaccine is safe and provides nearly 100% protection against infection. Vaccination is generally administered in a series of doses and is recommended for all newborns, children, and adults up to age 59.
Hepatitis C Virus (HCV): Characteristics and Risk
Like HBV, the Hepatitis C Virus primarily attacks the liver and can result in both acute and chronic infection. A majority of people exposed to HCV (approximately 70% to 85%) will develop a chronic infection. This chronic infection often remains asymptomatic for decades until severe liver damage, such as cirrhosis or liver cancer, becomes apparent.
HCV is a leading cause of liver transplantation in the United States. Unlike HBV, there is currently no preventative vaccine available for Hepatitis C because the virus has multiple genotypes and mutates frequently, posing challenges for development efforts.
Despite the lack of a vaccine, direct-acting antiviral (DAA) medications are highly effective treatments. These oral drug regimens are taken for a short period, typically 8 to 12 weeks, and can cure over 95% of people with the infection. The availability of this highly effective, curative treatment has transformed the management of chronic HCV.
Human Immunodeficiency Virus (HIV): Characteristics and Risk
The Human Immunodeficiency Virus targets the body’s immune system, specifically CD4 T-cells, which coordinate the immune response. By destroying these cells, HIV progressively weakens the body’s ability to fight off infections and certain cancers.
Without treatment, the infection can progress to Acquired Immunodeficiency Syndrome (AIDS). AIDS is defined by a low CD4 count or the presence of specific opportunistic infections. However, modern medical management has transformed HIV into a manageable chronic health condition.
Antiretroviral Therapy (ART) involves a daily regimen of medication that suppresses the virus from replicating. This treatment allows the immune system to recover and prevents the progression to AIDS. Furthermore, when a person with HIV adheres to ART and achieves an undetectable viral load, the virus cannot be transmitted sexually, a concept known as Undetectable = Untransmittable (U=U). Pre-Exposure Prophylaxis (PrEP) is another preventative measure, involving medications taken by HIV-negative individuals at high risk to significantly reduce their chance of acquiring the virus.
Common Transmission Pathways and Prevention
The three bloodborne pathogens share several common routes of transmission. Sharing needles or syringes, particularly among people who inject drugs, is a significant transmission pathway for all three viruses. The viruses can also be transmitted through unprotected sexual contact involving semen, vaginal fluids, or rectal fluids.
Vertical transmission occurs when the virus is passed from a mother to her child during pregnancy, childbirth, or breastfeeding. Prevention strategies focus on interrupting these pathways. Preventing mother-to-child transmission, for example, involves screening and providing antiviral prophylaxis to the mother.
General prevention for the public includes practicing safe sex, avoiding the sharing of personal items that may be contaminated with blood (such as razors or toothbrushes), and ensuring sterile equipment is used for procedures like tattooing or piercing. Universal precautions, which treat all blood and body fluids as potentially infectious, are routinely followed in healthcare settings to minimize occupational exposure. For HBV, vaccination remains the most effective prophylactic measure for long-term protection.