PRIEST study

Pandemic Respiratory Infection Emergency System Triage

PRIEST study logo


Respiratory infections, such as influenza or the corona virus, affect the lungs and airways, causing symptoms including fever, sore throat, coughing and breathing difficulties. If a new strain of the virus becomes widespread across many countries, this can be classified as a pandemic. During a pandemic, more patients attend hospital services and require investigation or admission, which puts a huge strain on the NHS.

Patients who contact emergency services (via NHS 111, emergency ambulance services or emergency departments) with a suspected pandemic respiratory infection need to be rapidly assessed to determine the severity of their illness, and whether they need to be admitted to hospital. This process is called "triage". Triage often uses methods such as scores or decision rules. These have been developed and are ready for use in a pandemic, but we don’t know how well they can correctly predict who needs to be admitted to hospital, and who does not.

Research objectives

We aim to:

  • Optimise the triage of people using the emergency care system with suspected respiratory infections during a pandemic
  • Identify the most accurate triage method for predicting severe illness among patients attending the emergency department with suspected respiratory infection

Our specific objectives after the pandemic are:

  1. To determine the discriminant value of emergency department triage methods for predicting severe illness in patients presenting with suspected pandemic respiratory infection
  2. To determine the discriminant value of presenting clinical characteristics and routine tests for identifying severe illness
  3. To determine the independent predictive value of presenting clinical characteristics and routine tests for severe illness
  4. To develop new triage methods based upon presenting clinical characteristics alone or presenting clinical characteristics, electrocardiogram (ECG), chest X-ray and routine blood test results, depending upon the data available and the predictive value of variables evaluated in objective 3

The PRIEST study method

The PRIEST study uses patient data from the early phases of a respiratory infection pandemic, such as for COVID-19, to test how well existing triage methods predict serious complications patients. The study will also Identify cases where the triage methods did not predict serious complications or recommended unnecessary hospital admission, and where possible modify triage methods or develop new triage methods that predict serious complications better than existing methods.

To do this, during a respiratory infection pandemic recording we will be recording medical details in a standardised way from patients with suspected respiratory infection in a standard, using a triage form. We will then using hospital records to follow these patients up to 30 days on to find out if they die or suffer a life-threatening complication.

We will evaluate triage methods used to determine whether a patient suspected to be infected with pandemic respiratory infection should be admitted to hospital or not, and whether they should be admitted to intensive or high dependency care. These may include the CURB-65 score, PMEWS, the swine flu hospital pathway, SMART-COP, the SwiFT score and any new methods developed before the next pandemic. We will also develop two new triage methods based upon (a) presenting clinical characteristics alone and (b) presenting clinical characteristics, electrocardiogram (ECG), chest X-ray and routine blood test results.

The results of this study can be used in the following stages of the pandemic, to produce a guideline or rule to help decide which patients would benefit from being admitted to hospital. The findings can also help doctors and nurses identify which individual patients may go on to develop serious complications. We may also be able to identify which patient characteristics are associated with a higher risk of serious complications, such as age or underlying health conditions. For example, in the 2009 influenza pandemic, it was found that pregnant patients, and those suffering from obesity, were at higher risk of developing complications.

Patient information

The risks to patients involved in this study are very low, because the project will not involve any change to the way patients are assessed or treated. Information will be gathered in a way that aims to help doctors and nurses, and does not interfere with patient care. The way we collect information about patients has been tested during a winter flu season to confirm this.

Most personal details will be removed from information that leaves a hospital. We are only recording NHS numbers and ambulance incident numbers so that we can track how patients move through NHS services. Identifiable information, such as patient’s names, will only be available to local trained nurses who work alongside the care teams.

We will not be asking patients for written consent to use their data in the study because this could cause delays, which may be harmful in a pandemic. However, we will inform patients of the study, and let them know that they can remove their data if they wish.

Patients can contact one of the hospitals involved in the study to ask for their information to be removed from the study. This approach has worked well in previous studies, and was approved by an independent Research Ethics Committee and the National Information Governance Board. If you are included in the study at a hospital a member of hospital staff will hand you an information leaflet ways you can opt out at the time, either by filling out the leaflet and handing it back or by contacting a local member of the research team.

For more information on your rights in the study, and the locations where the research is being conducted please got to our Privacy notice located here.

Prehospital PRIEST study

Patients contacting NHS 111 or calling 999 with suspected COVID-19 infection need to be rapidly assessed to determine if they need an emergency ambulance. Those attended by an emergency ambulance then need to be quickly assessed to determine who needs to be taken to hospital and who can be advised to look after themselves at home. This process is known as "triage" and may use methods, such as scores or decision rules, which have been developed to assess the severity of illness and predict which patients are at risk of life-threatening complications. It is not currently known whether the triage processes used by NHS 111 and 999 services accurately identify who needs an emergency 999 ambulance and who then needs to be taken to hospital.

Research objectives:

We plan to use patient data from the early phases of the pandemic to:

  1. Test how accurately the triage methods used by NHS 111 and emergency ambulance responders identify people who need hospital admission,
  2. Identify cases where the triage methods recommended unnecessary hospital admission or did not predict serious complications,
  3. Use data collected by ambulance responders during their assessment to determine whether triage scores can improve triage decisions.


In order to assess the triage methods for NHS 111 and the emergency ambulance services, we will collect information that is routinely recorded when someone phones NHS 111 or is attended by a 999 ambulance, and then link this information to hospital records to determine whether the patient dies or suffers life-threatening illness.

The results of our study can be used to produce guidance for NHS 111 and 999 call handlers to help them decide which patients require an emergency ambulance, and guidance for emergency ambulance responders to help decide if patients need treatment in hospital. This guidance can be used in subsequent phases of the pandemic.

Patient information:

The risks to patients involved in the study are very low. The project will not involve any change to the way calls to NHS 111 or 999 are handled, or the way emergency ambulances respond to calls. We will use identifiable information (patient’s NHS number, date of birth, postcode and full name) to link ambulance data to hospital data and death records. We need to do this to find out what happens after someone has had contact with the ambulance service. This is particularly important in allowing us to identify patients who were advised to stay home who later deteriorated or needed to be treated in hospital. We have strict procedures in place to minimise access to the identifiable information. Only specific staff members, who are involved in collecting the ambulance service data, or linking the ambulance data with the hospital data, will see identifiable information. Identifiable data will be stored securely and deleted as soon as possible after the data has been linked. It will not be used for any other purposes or accessed by anyone else at any time.

As we will be using routinely recorded information, which has already been collected by the ambulance service, we will not be able to ask patients for consent to use their data. However, patients can contact the PRIEST study team ( to “opt out” of the study and to request that their information is not included in the study. In addition, patients national opt out choices will be respected and data for patients who have opted out will not be included in the study. Further information on the national opt out service is available here:

Study team



Carl Marincowitz

Chief Investigator

Steve Goodacre

Chief Investigator (PRIEST)

Ben Thomas

Study Manager

Fiona Bell

Local Collaborator for YAS

Richard Pilbery

Research Paramedic

Laura Sutton


Janette Turner

Honorary Senior Research Fellow

Tony Stone

Co-Investigator and Data Management Lead

Ric Campbell

Data Specialist

Suvodeep Mazumdar

Data Analytics

Frank Hopfgartner

Senior Lecturer in Data Science

Josie Bourke

Trial Support Officer

Study outputs

Updated 08/02/21

Published articles

Articles currently in pre-print

PRIEST Covid-19 triage tool

PRIEST COVID-19 clinical severity score summary

Study impact

The PRIEST score has been recommended for prognostication by the American College of Emergency Physicians.

The PRIEST score can be found on MDCALC.

A modified version of the PRIEST score has been validated in a US study.


This project is funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA) Programme (project number 11/46/07). Any views or opinions expressed are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, NHS or the Department of Health.

Study team

Name Site Role Phone Email
Professor Steve Goodacre ScHARR Chief Investigator +44 114 222 0842
Carl Marincowitz ScHARR Chief Investigator (Pre-hospital PRIEST)
Dr Benjamin Thomas ScHARR Study Manager +44 114 22 24024
Katie Biggs ScHARR CTRU Oversight +44 114 22 26128
Laura Sutton ScHARR Statistician +44 114 222 4055
Amanda Loban ScHARR Data Management +44 114 222 2995
Josie Bourke ScHARR Trials Support Officer +44 114 222 4311

Project management group

Name Site Role Phone Email
Dr Kirsty Challen Lancashire Teaching Hospitals NHS Foundation Trust Consultant in Emergency Medicine
Dr Andrew Bentley University Hospital of South Manchester Critical Care Expertise +44 161 291 6420
Dr Darren Walter University Hospital of South Manchester Expert in Pandemic Emergency Planning +44 161 291 6047
Dr Ian Maconochie St Mary's Hospital, London Expert in Paediatric Emergency Medicine +44 207 886 6139
Dr Chris Fitzsimmons Sheffield Children's Hospital Expert in Paediatric Emergency Medicine +44 114 271 7431
Andrew Lee ScHARR, The University of Sheffield Senior Clinical University Teacher +44 114 222 0872
Fiona Lecky ScHARR, The University of Sheffield Principal Investigator +44 114 222 0834
Tim Harris Barts Health NHS Trust Principal Investigator


List of Trusts/Hospitals and Principal Investigators

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