Approximately five blood donations a year infected with hepatitis B, and one donation every twelve years infected with HIV or hepatitis C enter the United Kingdom's blood supply, according to a study published in the May 2003 edition of the journal Vox Sanguinis.
Figures from the UK’s National Blood Service show that there are in the region of 20 HIV-infected donations a year detected by screening, 130 hepatitis C-infected donations and 110 infected by hepatitis B.
These figures were too low for the investigators to provide an accurate estimate of how many infections would slip through the screening process. However, using data on the incidence of HIV antibodies seen in blood donations between 1993 and 2001, together with information about the length of the negative ‘window-period’ between exposure and seroconversion, and the accuracy of testing assays, the investigators calculated that one in eight million blood donations in the UK will be infected with HIV and enter the blood supply.
The same exercise was also conducted for hepatitis B and hepatitis C and suggested that the figures for hepatitis B were one in every 260,000 donations and one in every 520,000 for hepatitis C before 1998, the chances decreasing to one in every 30 million from 1999.
As the National Blood Service receives 10,000 donations every working day, this means that five hepatitis B-infected donations a year are likely to enter the blood supply, with an HIV or hepatitis C-infected donation entering the blood supply once every twelve years.
Figures from the National Blood Service broadly support these estimates, although they show that receiving potentially infectious blood does not always result in infection. A total of six people have received HIV-infected donations, resulting in two cases of HIV transmission one in 1986 and one in 1996. There have also been two cases of hepatitis C transmission, one in 1996 and one in 1997.
Hepatitis B transmission from the blood supply has been more common, with seven cases between 1995 and 2000.
Measures have been in place to protect the UK blood supply from HIV since 1985. These include a blanket ban on gay men giving blood. People from other communities at high risk of HIV are also banned from giving blood, as are people who have had ear or body piercing, acupuncture or a tattoo. The ban on gay men donating blood, regardless of their HIV status, sexual history, or risk behaviour has been attacked as homophobic by some community activists. However, the ban is supported by the UK’s largest HIV charity the Terrence Higgins Trust, and a detailed document outlining the reasons for their support can be viewed here. Bans are also in place on blood donation by black Africans, sex workers, and injecting drug users. Other people unable to give blood include those who travelled to areas where malaria is endemic, and people who have had surgery in the last twelve months. Click here to visit the National Blood Service's questionnaire on who can give blood.
Soldan K et al. Estimation of the risk of hepatitis B virus, hepatitis C virus and human immunodeficiency virus infectious donations entering the blood supply in England, 1993 – 2001. Vox Sanguinis 84: 274, 2003.