What bloodborne viruses are

Bloodborne viruses (BBVs) are viruses that are carried by some people in their blood and can be spread from one person to another.

Those infected with a BBV may show little or no symptoms of serious disease, but other infected people may be severely ill. You can become infected with a virus whether the person who infects you appears to be ill or not – in fact they may be unaware they are ill as some persistent viral infections do not cause symptoms.

An infected person can spread BBVs to another person by various routes and over a prolonged time period.

The most common BBVs

The most prevalent BBVs are:

  • human immunodeficiency virus (HIV) - causes a disease affecting the body's immune system which can progress to acquired immunodeficiency syndrome (AIDS)
  • hepatitis B (HBV) and hepatitis C (HCV) - viruses causing hepatitis, a disease affecting the liver

You can find NHS guidance that covers the symptoms, causes and treatment of:

There is also HSE guidance on how to prevent bloodborne virus exposure in your workplace. It includes an explanation of how someone who is receiving modern antiretroviral therapy (ART) will in most cases have undetectable levels of the HIV virus in blood. For such individuals, their risk of transmitting HIV through sexual contact is effectively reduced to zero and significantly reduced via blood.

How BBVs are transmitted

BBVs are mainly transmitted through blood. However, these viruses can also be found and transmitted through other body fluids, for example:

  • vaginal secretions
  • semen
  • breast milk

Unless contaminated with blood, minimal risk of BBV infection is carried by:

  • urine
  • saliva
  • sweat
  • tears
  • sputum
  • vomit
  • faeces

The presence of blood in these bodily fluids and materials is not always obvious, so always take care to avoid infection.

You can find HSE guidance on how bloodborne viruses can be spread in workplaces.

Other sources of advice

HIV

Hepatitis B

Hepatitis C

Is this page useful?

Updated 2025-04-15