Research and analysis

HPR volume 8 issue 29: news

Updated 23 December 2014

1. Transfusion transmitted infections, UK 2013

Details of possible transfusion-transmitted infection incidents that were investigated by the United Kingdom Blood Service in 2013 have been published in the latest Serious Hazards of Transfusion (SHOT) annual report [1].

The risks of a component potentially infectious for hepatitis B virus (HBV), hepatitis C virus (HCV) or HIV being released for use in the UK are very low. However, haemovigilance is maintained and investigations performed if a recipient is suspected of having been infected via transfusion.

UK Blood Service investigations in 2013 confirmed:

• one probable transfusion-transmitted HBV incident investigated in 2013 following a transfusion in 2012;
• one hepatitis E virus (HEV) transfusion-transmitted incident pending from a 2012 investigation;
• no proven bacterial transfusion-transmissions reported in 2013;
• one ‘near-miss’ bacterial incident.

Bacterial contamination of a component remains possible despite screening of platelets and the Blood Service should be informed immediately of all adverse reactions and events, including those suspected of being the result of bacterial contamination of a component.

The UK Blood Service’s Standing Advisory Committee on Transfusion Transmitted Infection (SACTTI) is alerted to any new infectious threats to the UK blood supply through a wide range of reporting mechanisms, and will commission risk assessments where necessary to inform decisions on whether action should be taken to protect the safety of the blood supply [2].

A retrospective hepatitis E virus (HEV) study – conducted jointly by NHSBT and Public Health England to address the growing concern about HEV and blood safety – detected high HEV-RNA incidence (0.03%) in blood donors in England at the time of donation. This was associated with HEV transmission to 42% of recipients, with eventual clearance confirmed in those cases where prolonged follow-up was possible [3].

The SHOT annual report [1] provides a fuller description of incidents investigated in 2013 and a cumulative table of UK TTIs between 1996 and 2013.

Further information is available from the NHSBT/PHE Epidemiology Unit at epidemiology@nhsbt.nhs.uk.

1.1 References

1. Serious Hazards of Transfusion (SHOT) annual report, 9 July 2014. Available at: http://www.shotuk.org/shot-reports/report-summary-supplement-2013/

2. Joint UK Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee (JPAC) Position Statement on Emerging Infections (June 2013).

3. Hewitt PE, Ijaz S, Brailsford SR, Brett R, Dicks S, Haywood B, et al. “Hepatitis E virus in blood components: a prevalence and transmission study in southeast England”, The Lancet (early online publication), 28 July 2014.

2. Legionnaires’ disease in England and Wales 2012

The latest annual report on Legionnaires Disease in residents of England and Wales has been published by Public Health England on the www.gov.uk website describing the epidemiological features of confirmed cases with onset of symptoms in 2012 [1,2].

A total of 309 confirmed cases were reported in 2012 of which 54.9% were deemed to be community-acquired (a category which includes cases that may have been associated with travel within the UK) . 41% of all cases (127) were associated with travel abroad. Eleven cases (3.6%) were thought to have been healthcare-associated/nosocomial.

Cases associated with travel abroad fell as a proportion of all England-and-Wales cases – from 49% (116) of all cases in 2011 to 41% (127) in 2012. Sea cruises, and travel to Turkey and Greece ranked highly, taking account of the extent of travel and participation by England and Wales residents. However, in terms of absolute numbers, travel to Spain was the destination associated with the highest number of cases (41) in England and Wales residents.

Legionnaires’ disease remains an important cause of both morbidity and mortality in England and Wales. The elderly continue to account for most infections and deaths, for which the age profile is heavily weighted to the over-sixties. Those aged between 60 and 69 account for the highest proportion of cases overall. At least one underlying condition or risk factor was found in 193 of the 306 cases in 2012. Heart disease is the most commonly recorded underlying condition followed by smoking, diabetes and immunosuppression.

Over recent years the overall case/fatality ratio has remained high and little-changed. By type of exposure, fatality rate is highest for nosocomial cases (25% in 2012), more than twice the rate for all-exposures (10%), and nearly 5 times the rate for cases linked to travel abroad (95% CI). Those aged 70 years and over show by far the highest fatality rate of any age group.

Cases were detected in all regions of England and PHE has published separate epidemiological reports for each area covered by its 16 Centres, and a report for Wales. These are mainly concerned with analyses of data relating to cases with onset of symptoms in 2012, but data describing trends over recent years are also presented.

Sixteen clusters/outbreaks were identified in England and Wales in 2012. During the 3 years 2010 to 2012 – for which time-averaged incidence data is presented in the report – two particular outbreaks were identified and investigated that impacted on peak incidence data: one in Wales in 2010 [3], and one in the West Midlands in 2012 [4].

2.1 References

1. Legionnaires’ disease in England and Wales 2012, https://www.gov.uk/government/publications/legionnaires-disease-in-england-and-wales-2012.

2. PHE news story “Latest Legionnaires’ disease data published for England and Wales”..

3. Public Health Wales report on “Heads of the Valleys” LD outbreak, HPR 6(31), August 2011.

4. HSE notice on management of legionella risks following Stoke-on-Trent outbreak, HPR 7(32), August 2012.