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Bristol researchers to collaborate on national study to understand long COVID

Press release issued: 18 February 2021

What is long COVID and how can diagnosis be improved? Using data from electronic health records at a national scale alongside information from thousands of participants in the UK's population-based cohort studies, these and other questions will be tackled following today's [18 February] announcement of a nationwide long COVID study led by University College London (UCL). The study will include Bristol’s Children of the 90s health study, based at the University of Bristol.

The project, 'Characterisation, determinants, mechanisms and consequences of the long-term effects of COVID-19: providing the evidence base for health care services', will be led by Nishi Chaturvedi, Professor of Clinical Epidemiology at UCL and is funded by a £9.6 million NIHR-UKRI grant.

Around 90 per cent of people with COVID-19 infection are not admitted to hospital: many have minimal or no symptoms.  Most recover completely, but a meaningful number report persistent and disabling physical and mental health symptoms - post-COVID-19 syndrome, known as 'long COVID'. Current projections estimate 1 in 20 people with a COVID-19 infection will still have symptoms beyond 2 months - meaning a substantial healthcare investment is needed to treat and support those with the condition.

Our understanding of long COVID, including how best to diagnose, risk factors, health and economic consequences, is poor, limiting efforts to help people struggling with the condition. Studies to date have used hospitalised cases or volunteers from the general population, potentially missing relevant patient data and introducing bias. This study - the first of its kind to look at long COVID - will use national electronic health records combined with the UK’s population-based cohort studies to overcome these issues.

It will address the following questions:

  • What is long COVID and how can it be diagnosed?
  • What are the risk factors for long COVID?
  • What are the impacts of long COVID on health, finances, family and wellbeing?
  • What primary care treatment and support plans will best support those affected?

The UK is uniquely placed globally in the richness of its population cohort studies spanning the country, covering all age and socioeconomic groups, and including hard to reach groups including ethnic minorities. It is estimated that one in 30 people in the UK are part of a cohort study, contributing data and samples to a health study throughout their life.

By linking together cohort studies' detailed pre-pandemic health data and using national anonymised, linked GP electronic health records, this study will seek to understand the nature of long COVID, risk factors and its impact.

Participants in Children of the 90s study (along with other cohort studies' participants) will report on their long COVID symptoms by wearing a wrist band to measure exercise ability, breathing, and heart rate. They will also be asked to complete online questionnaires on mental health and cognitive function.  Subsequently, participants will then be invited to visit a London clinic for non-invasive imaging to look at potential damage to vital organs, such as the brain, lungs and heart.

Professor Nic Timpson, Principal Investigator at Children of the 90s, said: "Bristol's Children of the 90s participants should be proud that through their contribution, this study will enable better diagnostic tools for long COVID, and a clearer understanding of the condition itself.

"Population health studies and linked health records offer an important mechanism to study long COVID and its impact, with decades of detailed health data and our participants’ long-term contribution to science and health research."

Jonathan Sterne, Professor of Medical Statistics and Epidemiology, University of Bristol, Director of Health Data Research UK South West and Deputy Director of the NIHR Bristol Biomedical Research Centre (NIHR Bristol BRC), added: "Bristol researchers will play a major role in the teams analysing electronic health record information from the whole population, datasets based on up to 54 million people.”

John Macleod, Professor of Clinical Epidemiology and Primary Care, Director of NIHR Applied Research Collaboration West (ARC West) and Joint Head of the Centre for Academic Primary Care and NIHR School for Primary Care Research, said: “Thankfully most people with COVID-19 are never admitted to hospital but they may still experience long-term effects of their infection and these may be different from those seen in hospitalised patients. We need to understand this to give people the best help.”

Findings from the study will be shared with bodies involved in developing guidelines (NICE, who are also part of this project), with government (via the Chief Scientific Advisor), with the public via social media and other outputs, and the scientific community via research publications.

Further information

The four research NIHR-UKRI funded studies to help understand and address the longer term effects of COVID on physical and mental health are: 

  • REACT long COVID (REACT-LC), led by Professor Paul Elliott, Imperial College London - £5.4 million over 3 years. The study will involve people in the community who have taken part in the REACT study of the virus that causes COVID-19. The data from these studies will be analysed to find factors affecting why some people get Long COVID and others don’t. The biological studies will help us understand mechanisms causing persistent symptoms and may point to possible treatments.
  • Therapies for long COVID in non-hospitalised individuals: from symptoms, patient-reported outcomes and immunology to targeted therapies (The TLC Study), led by Dr Shamil Haroon and Professor Melanie Calvert, University of Birmingham - £2.3 million over 2 years. The study will identify which treatments are most likely to benefit people with particular symptoms of long COVID and test supportive treatments to improve their quality of life.
  • Characterisation, determinants, mechanisms and consequences of the long-term effects of COVID-19: providing the evidence base for health care services, led by Professor Nishi Chaturvedi, University College London - £9.6 million over 3 years. The study will use very large datasets created from electronic health records, linked to detailed data from more than 60,000 people, to help define what long COVID is and improve diagnosis. It will also explain why some people get the condition, the typical effects on a person’s health and ability to work, and the factors that affect recovery, to inform the treatments offered to patients.
  • Non-hospitalised children and young people with long COVID (The CLoCk Study), Professor Sir Terence Stephenson, UCL Great Ormond Street Institute of Child Health - £1.4 million over 3 years. The study will teach us more about long COVID among children, how it can be diagnosed and how to treat it.

About the National Institute for Health Research
The National Institute for Health Research (NIHR) is the nation's largest funder of health and care research. The NIHR:

  • Funds, supports and delivers high quality research that benefits the NHS, public health and social care
  • Engages and involves patients, carers and the public in order to improve the reach, quality and impact of research
  • Attracts, trains and supports the best researchers to tackle the complex health and care challenges of the future
  • Invests in world-class infrastructure and a skilled delivery workforce to translate discoveries into improved treatments and services
  • Partners with other public funders, charities and industry to maximise the value of research to patients and the economy

The NIHR was established in 2006 to improve the health and wealth of the nation through research and is funded by the Department of Health and Social Care. In addition to its national role, the NIHR commissions applied health research for the direct and primary benefit of people in low- and middle-income countries, using UK aid from the UK government.

About UK Research and Innovation (UKRI)
UK Research and Innovation (UKRI) works in partnership with universities, research organisations, businesses, charities, and government to create the best possible environment for research and innovation to flourish. We aim to maximise the contribution of each of our component parts, working individually and collectively. We work with our many partners to benefit everyone through knowledge, talent and ideas.

Operating across the whole of the UK with a combined budget of more than £8 billion, UK Research and Innovation brings together the seven research councils, Innovate UK and Research England.

About Children of the 90s
Based at the University of Bristol, Children of the 90s, also known as the Avon Longitudinal Study of Parents and Children (ALSPAC), is a long-term health-research project that enrolled more than 14,000 pregnant women in 1991 and 1992. It has been following the health and development of the parents and their children in detail ever since and is currently recruiting the children and the siblings of the original children into the study. It receives core funding from the Medical Research Council, the Wellcome Trust and the University of Bristol.

The study is helping scientists gain a detailed understanding of the biological, social, mental and physical impacts of COVID-19 over the short and longer term, using its resources to quickly answer policy questions that arise given current conditions.

Find out more at

About longitudinal studies
Longitudinal studies selecting a group of individuals or properties and then repeatedly collecting data on these people (or the people living in the properties). The groups of people – known as 'cohorts' – are typically chosen due to a common factor, such as cohorts of pregnant women or people living in a particular area or a specific age range. The value of longitudinal research lies in collecting a wide range of information, or data, then repeating it at regular intervals. The data allows researchers to investigate the interactions between different things that occur in individuals’ lives and how changes can lead to changing health status or personal circumstances.

It is estimated that over three million people in the UK are taking part in longitudinal studies. Many take part across a lifetime – the National Study of Health and Development is still collecting data from babies born in one week of 1946. 

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