Blood-borne viruses/ STIs

The Blood Borne Virus/STI team

The blood-borne viruses and sexually transmitted infections (STIs) team is responsible for surveillance and control activities for hepatitis B, hepatitis C, HIV, syphilis, chlamydia and other sexually transmitted infections. As these are all largely preventable by avoiding risks, and in the case of hepatitis B, by vaccination, we work with a wide range of partners to reduce the numbers of people infected and ensure good treatment. 

The multi-disciplinary team includes doctors, nurses and information officers. Some of the activities of the team include:

  • Contributing to surveillance of blood-borne infections and STIs
  • Ensuring actions are taken to prevent infections, working with a range of other healthcare professionals and voluntary groups
  • Following up notified cases of hepatitis to reduce onward transmission
  • Organising and contributing to education activities
  • Preparation of annual reports
  • Management of incidents and outbreaks
  • Chairing and contributing to work of Hepatitis B and C Managed Clinical Network


Transmission of HIV is predominantly through sexual intercourse, although it can also be transmitted by blood-to-blood contact and from an HIV-infected mother at birth. 

The immediate public health challenges remain consistent across the UK: increasing incidence and prevalence of HIV; early identification of those infected; rising costs of care; inequalities in disease distribution and determinants; and the associated mortality and long-term morbidity.

Hepatitis B

The hepatitis B virus (HBV) causes hepatitis (inflammation of the liver) and can also cause long term liver damage. There is a vaccine available to prevent hepatitis B infection, which should be given to all individuals who are at risk from hepatitis B infection.

Acute hepatitis B is acquired most commonly in the UK through vaginal or anal intercourse but is also acquired as a result of blood-to-blood contact (e.g. sharing of needles and other equipment by injecting drug users (IDUs), ‘needlestick’ injuries, sharing of razors/toothbrushes).  Acute infection may be asymptomatic or cause a mild to severe hepatitis. Of those infected, 5–10% will develop chronic hepatitis B, more likely in those infected as children.  

Chronic Hepatitis B is most commonly acquired through perinatal, sexual or household/social contact in countries with high or intermediate prevalence of chronic infection. Chronic hepatitis B may lead to severe liver damage. 

Hepatitis C

The hepatitis C virus was first identified in 1989. It is acquired mostly through blood-to-blood contact, although a small number may be sexually acquired.  Most people who are infected have mild or no symptoms initially, so are often unaware of their infection.  However chronic hepatitis C results in long-term liver damage for about 20% of those infected.

An estimated 4,000 people are infected in Northern Ireland with most unaware of their infection.

Sexually Transmitted Infections (STIs)

Sexually Transmitted Infections (STIs) are diseases that can be transmitted by unprotected sex, and include:

Chlamydia Genital Chlamydia trachomatis is the most commonly diagnosed STI in the United Kingdom. Highest rates are seen in  young people aged under 25 years.

Genital herpes Genital herpes simplex virus (HSV) infection is the most common ulcerative sexually transmitted disease in the UK. Symptoms can start with mild soreness and groups of small painful blisters appearing on the genitals and surrounding areas. Further episodes of these symptoms can occur from time to time as recurrent episodes.

Genital warts There are many (over 100) types of Human papillomavirus (HPV), around 40 of which are sexually acquired and can infect the genital tract. Certain genital HPV infections can cause cervical cancer, other cancers and genital warts.

Gonorrhoea Neisseria gonorrhoea is the second most common bacterial STI in the United Kingdom.  Young people are most commonly infected, with current rates highest in males aged 20-24 years and females aged 16-19 years

Syphilis Syphilis is caused by a bacterial spirochete Treponema pallidum subspecies pallidum. Syphilis can be transmitted between partners during sexual intercourse and from an infected pregnant woman across the placenta to a developing baby.

Young people are at particular risk of chlamydia and genital wart infections, and men who have sex with men (MSM) are disproportionately at risk of HIV, infectious syphilis and gonorrhoea.

A more detailed analysis of HIV and STIs is presented in the Public Health Agency (PHA) annual STI and HIV surveillance reports. The reports are available on the PHA website at: Report on surveillance of BBVs and STIs in Northern Ireland

Key links

Public Health England website contains useful information on all blood-borne viruses and STIs, follow links to individual disease pages

Northern Ireland Hepatitis B and C website

Surveillance of sexually transmitted infections in Northern Ireland

Genitourinary Medicine (GUM)/Sexual Health Clinics in Northern Ireland