Last reviewed 7 January 2022

Mike Sopp advises on the practicalities of investigating and managing an outbreak of Covid-19 in the workplace.

As the UK continues to recover from the coronavirus pandemic and restrictions are gradually relaxed, employers are preparing for increasing numbers of employees to return to normal work practices.

However, the relaxation of restrictions increases the potential for employees to become infected with the virus.

Where a Covid-19 “outbreak” occurs in the work environment, undertaking an investigation into the circumstances of the outbreak will assist employers in meeting their legal duties and best practice guidelines.

Why investigate an outbreak

Current guidelines for employers in relation to managing the risks from Covid-19 recommend “an up-to-date plan in case there is a Covid-19 outbreak”.

According to the Government, an outbreak is when there are two or more test-confirmed cases of Covid-19 among individuals associated with a specific non-residential setting, with illness onset dates within 14 days, and one of the following:

  • identified direct exposure between at least two of the test-confirmed cases in that setting (for example under one metre face to face, or spending more than 15 minutes within two metres) during the infectious period of one of the cases

  • when there is no sustained local community transmission, ie the absence of an alternative source of infection outside the setting for the initially identified cases.

Employers may be notified of confirmed cases by a number of means including directly by employees, NHS Test and Trace or the local public health Health Protection Team (HPT).

Organisations should have procedures in place that enable them to implement any necessary actions. This could include undertaking an internal investigation of the outbreak.

Such an investigation could have a number of purposes including:

  • enabling immediate action to be taken to mitigate the impacts of the outbreak by reducing the spread of the virus

  • assisting with investigations undertaken by external parties such as the HPT by collating all relevant information

  • meeting legal obligations by reviewing whether the risk control measures implemented were satisfactory

  • giving assurance to stakeholders that the organisation is meeting its due diligence requirements

  • providing information to determine whether the outbreak would require a formal report to be made to the relevant enforcing authority

  • assisting in any defence against formal investigations/enforcement action and civil claims.

Collating information

Clearly any employee testing positive should self-isolate but, as UK Government guidance notes, “it is an offence for you (as an employer) to allow a worker to attend the workplace if you are aware that the worker has been in close contact with someone who has tested positive and they have received a notification to self-isolate from NHS Test and Trace”.

Employers are also required to contact the “Self-Isolation Service Hub” and provide the names of any employees/co-workers identified as close-contacts of infected individuals.

To comply with the above, the organisation’s investigation should gather information and identify close contacts through records of shift patterns and working locations, etc.

As part of outbreak planning, the employer should begin immediately to liaise with the relevant authorities (eg the HPT) who will, based upon the information available, determine the best course of action to take. This may include establishing an Incident Management Team to investigate in detail the circumstances of the outbreak.

The employer will be asked to provide relevant information to enable the HPT to undertake a risk assessment. Therefore, the investigation procedure should include the collation of information that includes:

  • contact details of the people infected

  • when the individuals became unwell

  • when they were last present on the premises

  • sickness absence records

  • nature of the job undertaken by any staff

  • known links between individuals with Covid-19 (in or out of the premises)

  • number and details of people with whom they had close contact

  • nature of the environment (eg layout and nature of the building)

  • details of risk assessment and risk control measures.

Internal investigation

External authorities such as HPTs will determine what action to take, based upon the information collated as detailed above.

However, the employer may wish to undertake an internal investigation into the circumstances of the outbreak, which may certainly be influenced by the outcomes of any HPT investigation.

An outbreak is not necessarily attributable to failings in terms of the control of the risks associated with Covid-19.

But it should be borne in mind that, under the Management of Health and Safety at Work Regulations 1999, employers have a legal duty to review risk assessments where there is reason for them to be no longer valid. It can certainly be argued that an outbreak could constitute as being within this scope.

At the very least an investigation will give an insight and an understanding of:

  • how the exposure may have occurred

  • how Covid risk control measures are actually being applied

  • how employees are behaving in relation to the risk control measures

  • how to enhance current practices.

Like all investigations, the investigation into a Covid outbreak will involve the analysis of all relevant data. As well as the information noted above, additional data may include outcomes from the HPT investigation, records of any inspections undertaken relating to the application of Covid risk control measures, and concerns raised by employees or their representatives.

As with all investigations, analysis of the data should indicate the immediate, underlying and root causes. Examples of factors to consider include the following.

  • Premises: were physical social distancing guidelines applied in accordance with best practice? A physical inspection of the workplace may be required to determine layouts, traffic routes, signage, etc.

  • Equipment: were workstations meeting best practice in terms of layout and additional risk control measures (eg screens between employees or employees and the public).

  • Processes and procedures: were employees following all appropriate procedures including social distancing, hygiene, use of face coverings, etc?

  • People: did they behave in an appropriate manner or was there a lapse in desired behaviour?

As with all immediate causes as generalised above, there are likely to be underlying or root causes that need to be analysed. Typically this will include:

  • determining if the risk assessment and risk control measures were suitable and sufficient, based against current best practice (such as guidance from the HSE and Covid-secure guidance)

  • whether there was adequate supervision and management of the application of Covid risk control measures

  • how the employer communicated the need to apply the risk control measures

  • what information, instruction and training employees were given so as to ensure they behaved in an appropriate manner

  • what monitoring took place to ensure the measures were being followed.

Finally, management actions should also be analysed. This could include identifying whether or not the organisation had the necessary competency to undertake the Covid risk assessment, if sufficient resources were given to applying risk control measures and whether any previous non-compliance was acted upon.

Where any areas for improvement are identified this should be recorded in an action plan and implemented.


An outbreak of Covid-19 in the workplace does not necessarily mean that there has been a failing on behalf of the employer to control Covid-19 in accordance with legal and best practice requirements.

However, by following good investigation procedures, the employer will be able to assist with any external investigations and ensure that all necessary legal and best practice requirements are being met.

As with any investigation, the collation of appropriate information is essential so that a full analysis can be undertaken.

This would involve identifying any potential root causes, underlying causes and managerial causes that may mean best practice is not being met.

Even where external investigations and internal investigations do not determine that there was a failing, undertaking an investigation can give assurance and confidence to stakeholders that the employer is meeting all due diligence requirements.