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  Title : #Assessment of #risk associated with #influenza A(#H5N8) virus, 17 November 2016. Subject : Avian Influenza, H5N8 subtype, multi...

22 Nov 2016

#NorthernIreland: #Outbreak of Serious #Pneumococcal #Disease in a #Belfast #Shipyard, April-May 2015 - Final Report (PHA, introduction)

 

Title: #NorthernIreland: #Outbreak of Serious #Pneumococcal #Disease in a #Belfast #Shipyard, April-May 2015 - Final Report.

Subject: Pneumococcal Pneumonia Outbreak, description and management.

Source: Northern Ireland (UK), Public Health Agency, full PDF file: (LINK). Introduction and discussion.

Code: [     ]

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Outbreak of Serious Pneumococcal Disease in a Belfast Shipyard, April-May 2015 - Final Report

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1. Introduction

  • This is the report of the interagency Outbreak Control Team (OCT) of an investigation of an outbreak of serious pneumococcal disease which occurred during April to May 2015 in a shipyard in Belfast.
  • Organisations and individuals represented on the OCT are provided in Appendix 1.
  • The report describes the chronology of the outbreak, control measures implemented, and the outcome of epidemiological, environmental health and microbiological investigations.
  • The report concludes with recommendations for Health and Safety Executive Northern Ireland (HSENI) to ensure all companies employing welders are aware of the guidance around personal protective equipment (PPE) and vaccinations, and for shipyard management and other employers of large transient multinational workforces to ensure provision of local occupational health services and general practice registration.

(…)

 

7. Discussion

  • This is the first outbreak of IPD in the context of an oil rig or ship yard setting that we are aware of.
  • Outbreaks of pneumococcal disease have been described in other settings including nursing homes, hospitals, schools, military camps and prisons11, and there are reports of outbreaks of other pathogens, including Influenza B, on an oil rig12.
  • Factors thought to have contributed to this outbreak include large numbers of individuals with increased susceptibility to IPD (due to metal fume exposure) working in close proximity, for prolonged periods in small, confined spaces on the oil rig, combined with the circulation of S. pneumoniae serotype 4, a serotype known to be associated with outbreaks.
  • The setting of this outbreak led to a number of complexities with regard to implementation of control measures.
  • One of the particular difficulties was the identification of close contacts at high risk, as recommended as part of PHE guidance.
  • There was no evidence of the four confirmed cases being part of a particular subgroup of oil rig workers.
  • All employees worked across all sections of the oil rig and did not operate in fixed groups.
  • The cases also did not share a single amenity block or employer.
  • Following discussion, it was agreed that all of those working on the rig with exposure to metal fumes (include welders, pipe fitters, steel workers and supervisors working closely with welders) should be offered antibiotic chemoprophylaxis and vaccination.
  • This amounted to an estimated 300 individuals, with the final total being significantly greater (680) due to widening of the occupational groups felt to be at increased risk.
  • The oil rig did not constitute a ‘closed setting’ in the way that a hospital or nursing home might, as the employees were only there during their working hours; other time was spent in the wider community, with overnight stays taking place in hotels across Belfast or private households.
  • Rig workers also shared common facilities with other dockside workers. This mixing decreased the likelihood that clearance of the organism would be fully achieved from the administration of chemoprophylaxis.
  • Additional difficulty in the implementation of control measures and management of symptomatic workers arose from the multi-national nature of the group at risk.
  • Of those working on the rig, approximately one third were ordinarily resident outside of the UK and a further third were resident in other parts of the UK outside Northern Ireland.
  • As a result, the majority of rig workers were not registered with a primary care provider in Northern Ireland. This, combined with the large size of the group needing prophylaxis and vaccination, meant that it was not appropriate to advise those in risk groups to attend primary care to arrange prophylaxis or vaccination.
  • Dedicated clinics were developed to ensure chemoprophylaxis and vaccination could be offered to all in the target group.
  • To complement the clinical workforce, interpreters were required to ensure adequate communication in a variety of languages, including Lithuanian, Polish and Russian.
  • While the majority of interpreters were obtained via BSO (Business Services Organisation), on occasion employees nominated a colleague to interpret for them, particularly for the less well represented languages e.g. Bulgarian. Availability of an appropriate interpreter was often noted to be the rate-limiting step at the clinics.
  • Over the course of the clinics, greater efficiency was achieved by ensuring those invited to the clinic matched interpreter availability for that particular time.
  • Many workers were on regular medications which required identification as they had been prescribed outside the UK and brought over by the worker.
  • Azithromycin is contraindicated with a number of routine medications so on site pharmacist advice provided assistance to prescribers where there was uncertainty.
  • An additional issue encountered was the lack of overarching occupational health oversight structures for the site.
  • Workers on the oil rig were provided by numerous different employers, including the shipyard, oil rig owner, six major and many minor contractors from across Europe.
  • Each employer had its own occupational health department; the majority of which were not located in Belfast. As a result, there was a lack of easily accessible occupational health support for the cohort of individuals working on the oil rig in Belfast.
  • National guidance recommends that consideration be given to the need for vaccination of welders with PPV 23 pneumococcal vaccine, taking into account occupational exposure control measures in place. Based on information collected from those attending the vaccination and prophylaxis clinics, only a small proportion (0.8%) recalled having received vaccination previously.
  • While it is emphasised that vaccination is not a substitute for PPE and other risk reduction measures, this outbreak suggests that exposure control measures alone may not always be sufficient to reduce the risk of pneumococcal disease.
  • Furthermore, welders may move between numerous workplaces, often across different countries, and the control measures in place may vary between locations.
  • It should also be noted that all of the confirmed cases and 42.5% of the employees attending the outbreak clinics were current smokers.
  • Smoking is also known to increase the risk of pneumococcal disease and so this may have increased the susceptibility to disease of those who became unwell. Employers of welders should be encouraged to offer smoking
    cessation services to their employees which may further reduce the risk of IPD in this susceptible group.
  • Two probable cases of IPD were reported in shipyard workers after the implementation of control measures. Although in at risk occupational groups these individuals had not received chemoprophylaxis or vaccination as they were off work at the time of the clinics. Although we are unable to account for the impact of the (planned) downscaling of the project workforce soon after the outbreak was recognised, these additional cases would appear to support the risk assessment and range of control measures as reported.

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{11} Ihekweazu, Chikwe, et al. Outbreaks of serious pneumococcal disease in closed settings in the post-antibiotic
era: a systematic review. Journal of Infection 61.1 (2010): 21-27.

{12} Johnston, F., et al. An outbreak of influenza B among workers on an oil rig. Communicable diseases
intelligence 21.8 (1997): 106-106.

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Keywords: UK; N. Ireland; Pneumococcal Pneumonia. S. Pneumoniae.

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