Research and analysis

HPR volume 9 issue 28: news (14 August)

Updated 29 December 2015

1. NHS Lothian investigation report on 2012 Edinburgh legionellosis outbreak

The report of a multi-agency investigation into the outbreak of Legionnaires’ Disease that occurred in south-west Edinburgh in the summer of 2012 has been published by NHS Lothian health board [1].

The outbreak was declared on Sunday, 3 June 2012, at which time five confirmed cases suggestive of a developing cluster had been notified. A ‘problem assessment group’ was converted, the same day, into a full incident management team (IMT), triggering a range of epidemiological, microbiological, environmental and meteorological investigations that are described comprehensively in the outbreak investigation report.

The IMT – chaired by an NHS Lothian consultant in public health medicine and including representatives from Edinburgh City Council, the HSE and Health Protection Scotland – continued functioning for a considerable period after the outbreak was declared over on July 17, so as to codify the lessons learned.

A total of 56 laboratory confirmed cases of Legionella Pneumophila meeting the outbreak case definition were recorded, including four deaths (a 7.1% case fatality rate). The case fatality rate for all 92 cases that were confirmed, probably or possibly linked to the outbreak was low at 4.3%. The IMT report nevertheless notes the considerable impact on NHS services, with more than 1,000 patients investigated and treated in primary care, 45 confirmed cases being admitted to local acute hospitals, 21 requiring admission to critical care and 19 ITUs. Seven confirmed cases lived outside of the NHS Lothian area.

Although no common source of infection could be definitively identified, the IMT/HSE investigations concluded that that the most likely source was an aerosol release (of Legionella Pneumophila Sg1 Knoxville ST191), in May, from an industrial complex containing wet cooling towers in the north east of the affected area. At the time of the outbreak, the HSE’s Health and Safety Laboratory had been preparing a research report on common contributory factors in legionella outbreaks from which the Lothian investigation benefitted [2].

Among the precautionary measures taken at the outset had been the ‘shot dosing’ with chemical disinfectant of all registered cooling towers within six kilometres of the centre of the original cluster. Two particular cooling towers in cluster area – identified as potential sources at an early stage of the investigation – had been among the first visited and shot-dosed, and voluntarily ceased operation on 7 June. HSE improvement notices were served on companies involved in the management of cooling towers and water systems at the two premises [3].

Consequential actions that followed the outbreak, or that benefitted from the lessons learned, included:

• revision of Scottish national legionella outbreak response guidance [4]

• review of the availability of Scottish resources and facilities required for rapid response, and for the duration of outbreaks

• training and exercising of Scottish joint agency plans

• publication by the European Centre for Disease Prevention and Control of an outbreak investigation toolbox [5].

1.1 References

1. NHS Lothian (6 August 2015). Legionnaires’ disease outbreak in south west Edinburgh June to July 2012: final report of the incident management team
2. HSL (2012). Legionella outbreaks and HSE investigations: an analysis of contributory factors
3. HSE (March 2015). Report on legionella intervention programme
4. Health Protection Scotland/HSE (November 2014). Guideline on the management of legionella cases, incidents, outbreaks an clusters in the community (revised, second edition)
5. ECDC. Legionnaire’s disease outbreak investigation toolbox.

2. New training resources for health professionals on meningococcal vaccination programmes

New training resources explaining changes to the national immunisation schedule – relating to protection against meningococcal disease, for different age groups – have recently been posted on the PHE webpages [1].

These include a dozen videotaped presentations explaining the background to new MenACWY and MenB immunisation programmes in England that involve a number of differently-timed changes to existing routine childhood and adolescent programmes, and a number of different “catch-up” programmes for ‘risk’ groups.

The changes start to be implemented this month, subject to vaccine availability (see below), with an urgent catch-up MenACWY programme for adolescents – particularly first-time university entrants, whether or not they have previously received a routine meningococcal disease capsular group C (MenC) vaccination.

Two MenACWY vaccines (Menveo® and Nimerix®) are being introduced in response to incidence of invasive meningococcal disease capsular group W (MenW) disease that after a steady increase from a low level since 2009 was deemed, at the start of 2015, to be an outbreak situation requiring an urgent response [2]. This vaccine will provide direct protection to the vaccinated cohort and, by reducing carriage of MenW, will also provide indirect protection to unvaccinated children and adults.

MenACWY vaccine ordering is temporarily suspended in England while delivery of further stocks is awaited. Ordering is expected to reopen later in August and vaccine made available as soon as it is received.

Due to the speed with which the MenACWY programme is being implemented, PHE is holding less vaccine buffer stock than would usually be the case for a national programme. This has increased the likelihood of periods of unavailability such as the current one. PHE is working to ensure that the supply disruption is minimised as quickly as possible and will provide regular updates through the ImmForm news items and Vaccine Update [3].

The new MenB vaccine (Bexsero®), protecting against meningococcal disease capsular group B, will be added to the childhood immunisation programme as part of the routine schedule in England from 1 September 2015.

Full guidance document collections relating to these two strands of the meningococcal immunisation programme are available at:

• Meningococcal ACWY (MenACWY) vaccination programme webpage

• Meningococcal B (MenB) vaccination programme webpage.

2.1 References

1. MenB and MenACWY programmes: a training guide for healthcare professionals.
2. Introduction of a meningococcal ACWY immunisation programme for adolescents. Part of the PHE guidance webpage MenACWY programme: information for healthcare professionals.
3. Vaccine Update (newsletter for immunisation practitioners) webpage.