Hepatitis refers to inflammation of the liver, most commonly caused by infection with one of several distinct hepatitis viruses. These viruses require a living host to replicate, but they possess a varying ability to endure outside the human body. The duration a hepatitis virus can remain infectious on a surface dictates the risk of indirect transmission and informs necessary public health measures. Understanding this survival period is important for preventing unintended exposure in various settings.
Comparing Survival Times of Hepatitis Types
The stability of hepatitis viruses outside the host differs significantly based on the specific type, with Hepatitis B (HBV) demonstrating the greatest resilience. HBV is a highly stable virus that can maintain its infectious properties for at least seven days on environmental surfaces at room temperature. Studies suggest the virus can persist for up to four weeks or longer, particularly when encased in dried blood or other bodily fluids. This extended viability makes HBV a considerable concern for transmission via contaminated objects.
Hepatitis C (HCV) is generally considered less robust than HBV, but it still poses a measurable threat outside the body. Research shows that HCV can remain viable and infectious on surfaces for up to six weeks under specific room temperature conditions. This persistence is especially relevant in contexts where blood spills may occur and not be immediately cleaned.
In contrast to the bloodborne viruses, Hepatitis A (HAV) is primarily transmitted through the fecal-oral route and exhibits a different type of environmental hardiness. HAV is a non-enveloped virus, a structural feature that provides increased resistance to environmental stresses and common disinfectants. Because of this structure, HAV can survive for extended periods on surfaces, potentially remaining infectious for up to a few months. This longevity underscores the need for strict hygiene practices, especially in food preparation and restroom sanitation.
Factors Influencing Viral Viability
The survival time of a hepatitis virus outside the body is influenced by several environmental elements. Temperature is one of the most impactful factors, as cooler conditions generally support viral longevity. Studies on HCV, for instance, found that the virus remained active for longer periods at refrigerator temperatures compared to body temperature. Warmer temperatures accelerate the degradation of the viral structure, leading to a faster loss of infectivity.
The type of surface on which the virus resides also plays a role in its viability. Viruses tend to survive longer on non-porous materials like stainless steel, plastic, and glass compared to porous materials like fabric or paper. Non-porous surfaces do not absorb the bodily fluid, allowing the virus to remain on the surface layer where it is more easily transferred.
The presence of organic material, such as blood or other bodily fluid, acts as a protective shield for the viral particles. When the virus is suspended in a larger volume, it is more insulated from desiccation and environmental degradation. This high concentration of organic material is particularly protective for HBV, enabling it to persist for longer periods in dried blood on objects. The amount present on the surface is a significant determinant of how long a virus remains a potential source of infection.
Common Transmission Pathways Outside the Body
For the bloodborne viruses, HBV and HCV, transmission outside the body centers on the movement of infected blood from one person to a surface or object, and then to a susceptible person. This often involves indirect contact with contaminated sharps, such as needles or syringes used for injection, which may retain infectious traces of blood. Even after the blood has dried, the virus can remain active and pose a threat if introduced into a break in the skin or a mucous membrane.
A common route of transmission outside of medical settings involves shared personal grooming items that may carry trace amounts of blood. Objects like razors, nail clippers, tweezers, and toothbrushes can become contaminated with microscopic particles of blood and serve as vehicles for HBV or HCV transfer. The hardiness of HBV makes the risk from these household items particularly relevant for individuals living in the same residence as an infected person. Any object that pierces the skin or causes bleeding should not be shared.
The transmission pathway for HAV is entirely different, relying on the fecal-oral route. This occurs when an object or surface is contaminated with microscopic amounts of stool from an infected person, typically due to inadequate handwashing after using the toilet. The virus can then be transferred to another person’s mouth, either directly by touching the contaminated surface and then their face, or indirectly through contaminated food or water. Because of this pathway, surfaces in restrooms and kitchens are frequent points of concern for HAV transmission.
Protocols for Surface Disinfection
Cleaning and disinfecting surfaces contaminated with bodily fluids is a multi-step process that minimizes the risk of indirect hepatitis transmission. Before beginning, it is important to don appropriate personal protective equipment (PPE), including disposable gloves, and potentially a gown and eye protection, especially when handling significant blood spills. This barrier protection prevents direct contact with the infectious material.
Pre-Cleaning
The first step in surface decontamination is to remove the visible organic material, which is known as pre-cleaning. This involves carefully blotting up blood or other fluids with disposable absorbent material, such as paper towels. The soiled material and the outer set of gloves must then be discarded into a leak-proof plastic bag. Removing this bulk material is important because the proteins in blood can reduce the effectiveness of many disinfectants.
Disinfectant Application
After the surface is visibly clean, an appropriate virucidal disinfectant must be applied to inactivate the remaining viral particles. A common and highly effective disinfectant is a freshly prepared solution of household bleach. For general disinfection of non-porous surfaces, a dilution of 1 part bleach to 10 parts water is often used. A more specific mixture of 1 and 2/3 cups of bleach per gallon of water is effective against HAV.
Contact Time and Disposal
The disinfectant must remain on the surface for a specific contact time, or dwell time, to ensure the viruses are fully inactivated. For the bleach solution, a contact time of at least one minute is required before the surface can be rinsed with water and allowed to air dry. For surfaces sensitive to bleach, an EPA-registered hospital-grade disinfectant with a virucidal claim against HBV, HCV, or HAV can be used, with most requiring a contact time of four to five minutes. Following the disinfection, all used cleaning materials and PPE must be sealed in a plastic bag and disposed of properly to complete the process.