Research and analysis

HPR volume 10 issue 24: news (22 July)

Updated 16 December 2016

1. Transfusion transmitted infections (UK): 2015

A description of the possible transfusion-transmitted infection (TTI) incidents investigated by the United Kingdom (UK) Blood Service in 2015 has been published in the Serious Hazards of Transfusion (SHOT) Annual Report [1].

The risk of a screened component transmitting hepatitis B virus (HBV), hepatitis C virus (HCV) or human immunodeficiency virus (HIV) in the UK is very low [2]. Nevertheless, to maintain haemovigilance, investigations are performed if a recipient is suspected to have been infected via transfusion.

UK Blood Service investigations in 2015 have confirmed that there were:

• one proven bacterial transfusion-transmission reported in 2015
• one possible group B streptococcus transmission; although the investigation is complete, the source of the infection in the patient could not be confirmed
• two transfusion-transmitted hepatitis E virus (HEV) incidents and three cases where transfusion was not the source of HEV infection

The key messages for 2015 are:

• bacterial screening of platelets will reduce but not remove the risk of transfusion transmission of bacteria
• good practice and quick thinking of the hospital staff prevented further harm to the patient in the bacterial TTI in 2015 [3]
• haemovigilance is essential to identify incidents and inform hospital staff and other clinicians of safe practice

In 2015, the Advisory Committee on the Safety of Blood, Tissues and Organs (SaBTO) recommended that HEV negative components were required for specific patient groups:

• allogeneic stem cell/bone marrow transplantation
• solid organ transplantation

More details can be found at NHSBT Hepatitis E Screening. In order to supply HEV screen negative components for selected patient groups, UK blood centres are currently testing a proportion of whole blood and apheresis donations for HEV RNA; positive donors are being notified to the local Health Protection Teams.

Suspected transfusion transmitted infections should be reported to the blood services who can advise on the information required and how to proceed.

See the SHOT annual report [1] for a fuller description of incidents investigated in 2015, cumulative data by transfusion year and advice on action to be taken when it is suspected that a transfusion-transmitted infection incident has occurred.

1.1 References

1. NHSBT/PHE Epidemiology Unit (2016). Serious Hazards of Transfusion (SHOT) annual report.
2. NHSBT/PHE Epidemiology Unit (2015). Safe Supplies (annual review)
3. Morrison RRP, McDonald CP, Roy A, Allen J, Brailsford SR (2016). Bedside vigilance pays off: a case of confirmed Staphylococcus aureus transmission from a pooled platelet pack in the UK.

2. Malaria imported into the UK: 2015

Public Health England (PHE) has published its annual malaria report for the UK for 2015 [1].

In 2015, 1,400 cases of imported malaria were reported in the UK, 11.7% lower than reported in 2014 and 11.6% below the mean number of cases reported between 2005 and 2014. The majority of cases (76%) continue to be caused by the potentially-fatal Plasmodium falciparum parasite.

Of those with travel history/country of residence information available (976/1,400, 70%), the majority of malaria cases had travelled abroad from the UK (744/976, 76%), with most having travelled to visit friends and relatives in West Africa.

Six deaths were reported in 2015, compared to three in 2014, all from falciparum malaria acquired in Western Africa.

The latest report shows that malaria remains an important issue for UK travellers, particularly for those of African or Asian ethnicity who are non-UK born and going to visit friends and family in their country of origin. Failure to take chemoprophylaxis is associated with the majority of cases. Those providing advice should engage with these population groups wherever possible, including using potential opportunities to talk about future travel plans outside a specific health consultation, such as during new patient checks or childhood immunisation appointments [2].

The PHE Advisory Committee on Malaria Prevention Guidelines [3], and resources available from the National Travel Health Network and Centre, should assist clinicians in helping travellers to make rational decisions about protection against malaria.

Useful resources for travellers, including translated advice leaflets are available from the PHE website [4].

2.1 References

1. PHE (20 July 2016). Malaria imported into the United Kingdom (2015).
2. PHE website. Communicable Diseases: Migrant Health Guide.
3. PHE Advisory Committee on Malaria Prevention. Guidelines for malaria prevention in travellers from the United Kingdom.
4. PHE website. Malaria: guidance, data and analysis

3. Electronic Reporting System (ERS) for enhanced surveillance of carbapenemase-producing Gram-negative bacteria upgraded

PHE has launched an upgraded version of the electronic reporting system (ERS) that supports enhanced surveillance of carbapenemase-producing Gram-negative bacteria in England.

The ERS was first implemented in May 2015, the aims being:

• to improve understanding of the epidemiology of carbapenemase-producing Gram-negative bacteria in England and to monitor changes through better ascertainment of case details, and thereby
• to inform control measures to prevent the spread of carbapenemase-producing Gram-negative bacteria in healthcare settings.

The web-based ERS was designed to enable laboratories to request confirmation of carbapenemase-production from PHE reference or specialist laboratories and also to submit enhanced surveillance data for these organisms.

An ERS upgrade was rolled-out on 11 July 2016 to add additional functionality and improve the user experience following constructive feedback from laboratories and Trusts over the past 12 months. With the new features, users can now:

• record local molecular test results
• register multiple organisations and user roles
• produce reports for their laboratories and/or Trusts

With the increasing availability and use of commercial carbapenemase detection tests in NHS and private laboratories, the confirmation of carbapenemase production in Gram-negative bacteria is rapidly becoming a method for diagnostic microbiology laboratories rather than for reference laboratories. The ERS is the only method currently available that allows this locally-generated data to be captured and used to inform regional and national trends. Active participation in this surveillance by every Trust in the country is vital for building a comprehensive “picture” of the growing carbapenemase problem in England.

The ERS can be accessed at https://cro.phe.nhs.uk/. Supporting documentation for the system, including guidance on isolates to be referred for confirmatory testing and a step-by-step user guide can be found on PHE’s Carbapenem Resistance health protection collection webpages.

4. National outbreak of verocytotoxin-producing E. coli O157 phage type 34

On 21 June 2016, the South West PHE Centre observed higher than expected notifications of E. coli O157 cases from front line laboratories. An outbreak control team (OCT) was convened on 22 June to investigate this increase and, on the 24 June, the first samples associated with this increase were confirmed as VTEC serogroup O157 phage type 34, positive for the eae (intimin) and verocytotoxin 2 genes but negative for the verocytotoxin 1 gene. On 27 June a significant increase in the outbreak strain was observed nationally, and the incident was declared and managed as a national outbreak.

Analysis of whole genome sequencing data indicated that isolates fell within a 5-SNP (single nucleotide polymorphism) cluster, a strain not related to those currently circulating amongst the UK bovine reservoir. The outbreak strain was most closely related (> 70 SNPs) to sequences identified in people reporting recent travel to the Mediterranean region suggesting that the strain was likely to have been imported.

As at 14 July, a total of 158 cases had been identified of which 105 met the confirmed case definition and 53 the probable case definition [1]. Onset dates for primary cases ranged from 31 May 2016 to 5 July 2016 with cases identified in England (144), Wales (six) and Scotland (one). Reports of secondary transmission in households were infrequent. Cases were predominately female (119/158). Fifteen cases were under 18 years old and ages ranged from one to 98 years. As at 14 July, 62 cases were known to have sought tertiary care at some point during their illness (57 in England, four in Wales and one in Scotland). As at 14 July, four patients remained in hospital. Features of haemolytic uraemic syndrome (HUS) had been reported in seven cases. Two cases had died, both of whom had E. coli infection listed as a causative factor. The outbreak was characterised by multiple small clusters linked to catering and residential care premises with particular foci in the South West, South East and North West of England (see map in the full version of this report published on 19 July [1]).

As at 19 July, 5 July remained the latest symptom-onset date, suggesting that the worst of the outbreak has passed [2].

4.1 References

1. PHE (19 July). “National outbreak of verocytotoxin-producing E. coli O157 phage type 34”, HPR Advanced Access report, 19 July.
2. PHE (21 July). PHE website news story.

5. Infection and vaccine coverage reports in this issue of HPR

The following reports are published in this issue of HPR. The links below are to the relevant webpage collections or publications.

5.1 Infection reports

• Laboratory reports of hepatitis A and C (E&W): annual report 2015
• Hepatitis sentinel surveillance: annual report 2015

5.2 Vaccine coverage reports

• Shingles vaccine coverage report (England), September 2015 to May 2016
• Pneumococcal Polysaccharide Vaccine (PPV) coverage report (England), April 2015 to March 2016