First findings from world’s largest study on long-COVID in children

Funded by the UK’s National Institute for Health Research (NIHR) and UK Research and Innovation (UKRI), the research surveyed 3,065 11- to 17-year-olds in England who tested positive for COVID-19 in a PCR test between January and March 2021 as well as a control group of 3,739 11- to 17-year-olds who tested negative over the same period.

When surveyed an average of 15 weeks after their test this study found that a higher percentage of young people in the positive group had three or more symptoms of ill health (67%), including unusual tiredness and headaches, when compared to those who had previously tested negative for COVID-19 (53%).

The researchers said the data suggested that, between last September 2020 and March 2021, at least 4,000 (and possibly as many as 32,000 teenagers) of the total number of 11- to 17-year-olds who tested positive for COVID-19 in England may have had three or more symptoms linked to COVID-19 infection after 15 weeks.

The lower estimate (at least 4,000) relates to a best-case scenario, in which only the teenagers who responded to the survey had any persisting problems and those who chose not to respond the survey had completely recovered.

Co-lead author Professor Sir Terence Stephenson, Honorary Consultant at GOSH and Nuffield Professor of Child Health at UCL Great Ormond Street Institute of Child Health, said: “There is consistent evidence that some teenagers will have persisting symptoms after testing positive for SARS-CoV-2. Our study supports this evidence, with headaches and unusual tiredness the most common complaints."

In a briefing to journalists this week, the team commented that “...It’s important that those with persistent symptoms receive support but there is little evidence to suggest that large numbers of teenagers have sought NHS help for symptoms that have left them bedridden or unable to attend school, which is reassuring.”

The landmark study is the largest COVID study to date of children and young people in the world, recruiting from across the UK.

A large number of teenagers reported symptoms even though they had not tested positive for COVID-19 and the researchers identified three factors that may explain this. One is that symptoms such as unusual tiredness are common in this age group generally. The second is that the timing of the survey, between March and May, coincided with the return of school following lockdown and a likely increase in general illnesses. The third factor is that, of those young people sent a survey, only 13% responded – it is possible that these respondents were more likely to have poor health than those who did not respond.

Dr Isobel Heyman, Consultant Child and Adolescent psychiatrist at GOSH said: "A strength of our study is its parallel emphasis on mental health alongside physical health - in the pandemic and post-COVID. It is the first and largest study to ask children and young people to report directly about their own experiences."

The researchers found that there was no difference in mental health and wellbeing scores between children who tested positive compared to those who tested negative, but around 40% in both groups reported being a bit or very worried, sad or unhappy.

"There will of course be individuals with impaired mental health needs and these must be detected and treated rapidly and effectively in the usual way", Dr Heyman emphasised.

The research team sent questionnaires to around 220,000 young people in England and received 17,000 responses. This study drew on the responses of nearly 7,000 of those who were tested between January and March..

For future research, the team will analyse survey results at six months, a year and two years from the time of the PCR test.

The Children and young people with Long COVID (CLoCk) study is led by UCL and Public Health England and involves collaboration with researchers at the universities of Edinburgh, Bristol, Oxford, Cambridge, Liverpool, Leicester, Manchester as well as King’s College London, Imperial College London, Public Health England, Great Ormond Street Hospital and University College London Hospitals (UCLH).

Dr Jonathan Pearce, Director of COVID-19 Response, UKRI’s Medical Research Council said: “This study is very important as it will inform our understanding of the long-term impacts of COVID-19 on the physical and mental health of children and young people.

“Long COVID clinics are already open and helping thousands of people get support, anyone who is concerned about long lasting symptoms of the virus that are not improving as they would expect should get in touch with their GP practice or go online to the NHS 'Your COVID Recovery' website for advice.”

Preprint (not a paper): ‘Long COVID – the physical and mental health of children and non-hospitalised young people 3 months after SARS-CoV-2 infection; a national matched cohort study (The CLoCk) Study’by Terence Stephenson et al.  This work is not peer-reviewed.