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 an announcement on 18 February 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 and NIHR Bristol BRC Deputy Director Professor Jonathan Sterne is a lead collaborator.

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 NIHRUKRI 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.

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.”

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.”

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.