As a healthcare organisation you will be well aware of the risk of Legionnaires' disease and the fact that you are more vulnerable to legionella bacteria because of your large and complex water systems. You will also probably be familiar with the extensive guidance produced by Public Health England (PHE) and the Health and Safety Executive (HSE) on controlling and managing the risk of Legionnaires' disease. Indeed, it is likely that you will already have taken steps to ensure compliance with these.

What you may not have considered however is the development of a Legionnaires' disease Investigation Protocol, which sets out what should happen following the identification of a patient with suspected Legionnaires' disease. If you haven't yet developed such a Protocol we would strongly recommend you do this as a planned response ensures swift source identification and controlled management of the crisis, thereby containing the infection and minimising risk to other patients, visitors and staff.

This article provides quick step guidance on developing a Legionnaires' disease Investigation Protocol including suggestions on what steps should be taken by whom, and when.

Who should be involved?

You should first identify who will be the Protocol Lead. The Protocol Lead will be responsible for both developing the Protocol but also managing and ensuring it is complied with when a case of suspected Legionnaires' disease is identified. Ideally, the Protocol Lead should be someone in a senior management role with suitable experience and knowledge of Legionnaires' disease and / or infection prevention and control.

Identifying Possible Hospital Acquired Legionnaires' disease

The Protocol should set out clear instructions to clinical staff on how to identify 'possibly hospital acquired' Legionnaires' disease as timely and accurate diagnosis is crucial for managing the Trust's response.

If a patient's urine sample returns a positive sample for legionella, further specimen samples (such as sputum) should be requested and immediately sent for further testing. This is important as further specimen samples will provide detailed information on the type of Legionella bacteria causing the infection which will assist with source identification.

The protocol should also request that a clinical member of staff obtains from the patient a detailed account of their whereabouts during the disease's incubation period. If the patient stayed or spent any time at the hospital during the incubation period, the patient's Legionnaires' disease should be classified as 'possibly hospital acquired'.

Legionella Investigation Team

If a patient's Legionnaires' disease is classified as possibly hospital acquired, we would recommend that the Protocol dictates that the Protocol Lead should convene a meeting of the Legionella Investigation Team ("LI Team").

The LI Team should include, as a minimum, the following:

  • Microbiologists (the Protocol Lead may want to consider appointing an external Consultant in addition to internal Microbiologists);
  • Relevant representative/s from the Estates Department (in particular the Responsible Person for Water);
  • Relevant representatives from the IPC Team;
  • Senior Clinical staff members from the Ward(s) affected;
  • Representatives from the Organisation's Communications Team; and
  • Representative from the Cleaning Department.

You may also want to consider inviting a representative from PHE to provide expert input at the meeting.

Prior to the first LI Team meeting, your Protocol should set out what information should be acquired and by whom. For example, in order to aid with source identification, the Estates department may be asked to collate recent water sampling results.


Under statutory legislation, healthcare providers have a legal obligation to notify the Proper Officer of the Local Authority within three days of the date of suspicion of a person infected with Legionnaires' disease. In some cases, PHE will complete this notification. In any event, we would recommend that you notify PHE, and also the HSE if the patient is an employee. This is not only to utilise the specialist knowledge within these organisations but to ensure that close, cooperative working takes place at an early stage.

Your Legionnaires' disease Protocol should therefore set out who will be responsible for making the relevant notifications and when these will take place.

Developing a Strategy

Once the LI Team has been convened, they should work cohesively to develop a Legionnaires' disease Investigation Strategy, which sets out how the Investigation will proceed. The LI Team should consider the following as a minimum:-

  • The identification of potential source areas and accompanying risk assessments;
  • The development of a water sampling strategy to assist with source identification;
  • The development of a communications strategy to ensure patients and staff are aware of the incident and any steps they need to take to minimise the risk to others;
  • Any necessary site investigations of potential source areas; and
  • A plan for remedial action.

After the first LI Team meeting, we would recommend meetings every 2 to 3 days (or more frequently if required) so that updates can be provided, and the Strategy reviewed and amended where necessary.

Analysis of Results

It is likely that any healthcare provider affected by Legionnaires' disease will have both sample results from the patient and sample results taken from the water system. These will need to be compared to potentially identify the source of the infection. As this will involve analysing complex information regarding bacteria serogroups and types, we would strongly advise that the Protocol sets out a process for correctly interpreting these results, including when and how specialist microbiological advice should be sought. Care and caution in interpreting sample results is critical as swift and accurate source identification will underpin the Trust's response.

Concluding an Investigation

The Protocol should contain clear guidance on when and how the Investigation will be concluded and any steps that will need to be taken following closure of the investigation. For example, the Protocol may require the sharing of lessons learned.


Unfortunately due to the ever-challenging demanding world of healthcare, most healthcare providers are unlikely to consider producing a Legionnaires' disease Investigation Protocol until it is too late and the organisation is faced with a case of Legionnaires' disease. This reactive approach risks a confused and haphazard response which could delay or disrupt source identification and risk management and inadvertently permit an isolated case to become an outbreak.

We would therefore strongly recommend that you adopt a proactive approach and invest time now in developing a Legionnaires' disease Investigation Protocol. By preparing for the worst you will not only be minimising the risk of an outbreak but also doing what you can to prioritise patient safety.

For further information, or if you would like help drafting a Legionnaires' disease Investigation Protocol, please contact Ruth Atkinson-Wilks, Solicitor or Debbie Rookes, Associate.

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