Summary
Background
We describe post-COVID symptomatology in a non-hospitalised, national sample of adolescents aged 11–17 years with PCR-confirmed SARS-CoV-2 infection compared with matched adolescents with negative PCR status.
Methods
In this national cohort study, adolescents aged 11–17 years from the Public Health England database who tested positive for SARS-CoV-2 between January and March, 2021, were matched by month of test, age, sex, and geographical region to adolescents who tested negative. 3 months after testing, a subsample of adolescents were contacted to complete a detailed questionnaire, which collected data on demographics and their physical and mental health at the time of PCR testing (retrospectively) and at the time of completing the questionnaire (prospectively). We compared symptoms between the test-postive and test-negative groups, and used latent class analysis to assess whether and how physical symptoms at baseline and at 3 months clustered among participants. This study is registered with the ISRCTN registry (ISRCTN 34804192).
Findings
23 048 adolescents who tested positive and 27 798 adolescents who tested negative between Jan 1, 2021, and March 31, 2021, were contacted, and 6804 adolescents (3065 who tested positive and 3739 who tested negative) completed the questionnaire (response rate 13·4%). At PCR testing, 1084 (35·4%) who tested positive and 309 (8·3%) who tested negative were symptomatic and 936 (30·5%) from the test-positive group and 231 (6·2%) from the test-negative group had three or more symptoms. 3 months after testing, 2038 (66·5%) who tested positive and 1993 (53·3%) who tested negative had any symptoms, and 928 (30·3%) from the test-positive group and 603 (16·2%) from the test-negative group had three or more symptoms. At 3 months after testing, the most common symptoms among the test-positive group were tiredness (1196 [39·0%]), headache (710 [23·2%]), and shortness of breath (717 [23·4%]), and among the test-negative group were tiredness (911 [24·4%]), headache (530 [14·2%]), and other (unspecified; 590 [15·8%]). Latent class analysis identified two classes, characterised by few or multiple symptoms. The estimated probability of being in the multiple symptom class was 29·6% (95% CI 27·4–31·7) for the test-positive group and 19·3% (17·7–21·0) for the test-negative group (risk ratio 1·53; 95% CI 1·35–1·70). The multiple symptoms class was more frequent among those with positive PCR results than negative results, in girls than boys, in adolescents aged 15–17 years than those aged 11–14 years, and in those with lower pretest physical and mental health.
Interpretation
Adolescents who tested positive for SARS-CoV-2 had similar symptoms to those who tested negative, but had a higher prevalence of single and, particularly, multiple symptoms at the time of PCR testing and 3 months later. Clinicians should consider multiple symptoms that affect functioning and recognise different clusters of symptoms. The multiple and varied symptoms show that a multicomponent intervention will be required, and that mental and physical health symptoms occur concurrently, reflecting their close relationship.
Funding
UK Department of Health and Social Care, in their capacity as the National Institute for Health Research, and UK Research and Innovation.
Introduction
SARS-CoV-2 in children and young people is usually mild
1
- Molteni E
- Sudre CH
- Canas LS
- et al.
Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2.
compared with adults.
2
- Sudre CH
- Murray B
- Varsavsky T
- et al.
Attributes and predictors of long COVID.
However, little is known about the diagnosis, prevalence, phenotype, or duration of long COVID (also known as post-acute COVID syndrome) in children and young people.
3
- Chevinsky JR
- Tao G
- Lavery AM
- et al.
Late conditions diagnosed 1-4 months following an initial coronavirus disease 2019 (COVID-19) encounter: a matched-cohort study using inpatient and outpatient administrative data—United States, March 1–June 30, 2020.
The English National Institute for Health and Care Excellence (NICE) defines acute COVID-19 as disease with symptoms that last less than 4 weeks after confirmed infection. Ongoing symptomatic COVID-19 is defined as disease with symptoms lasting 4–12 weeks, and post COVID-19 syndrome as disease with symptoms lasting more than 12 weeks.
Research in context
Evidence before this study
This study was designed in November, 2020, when there was little known about long COVID in general and long COVID in children and young people in particular. Of the few publications, most reported data from clinical populations of children and young people seeking treatment and did not include controls. A search on July 26, 2021, of Medline, Cochrane, medRxiv, and PROSPERO, using the terms “COVID-19”, “sars-cov-2”, “child”, “adolescents”, “youth”, “young”, “long-COVID”, “sequelae”, “post acute” and “persistent”, from inception and with no language restrictions, did not identify any controlled, cohort studies of continuing symptoms following SARS-CoV-2 infection in non-hospitalised children or adolescents before our study was designed.
Added value of this study
This is a large cohort study of adolescents with PCR-proven SARS-CoV-2 status, not self-reported infection. The symptoms were reported by the adolescents themselves and, importantly, there was a matched test-negative group of adolescents who have lived through the pandemic but never tested positive for SARS-CoV-2. The participants were recruited nationally. Physical and mental health symptoms were described rather than undefined, self-reported long COVID. There was an increase in symptoms in adolescents who were either test-positive or test-negative 3 months after testing. The symptom profile was similar between the two groups but with a higher prevalence of symptoms in adolescents who tested positive than in those who tested negative and, importantly, adolescents who tested positive were more likely than those who tested negative to have multiple symptoms at the time of PCR testing and 3 months later. Subsequent waves of data collection will allow prospective tracking of mental and physical health symptoms in this cohort.
Implications of all the available evidence
We provide data on the presence of 21 physical symptoms and four wellbeing scales 3 months after SARS-CoV-2 testing in 6804 adolescents. Overall, this evidence shows the multiplicity and heterogeneity of long COVID in young people. These findings have implications for services, commissioners, researchers, clinicians, and affected families in understanding the prevalence and manifestation of long COVID in children and young people not accessing hospitals, and in informing health-care systems on service planning.
Ongoing symptomatic COVID-19 and post COVID-19 syndrome are referred to as long COVID
4
- Spiegelhalter D
- Masters A
Covid by numbers: making sense of the pandemic with data.
but the term post COVID-19 condition is also used. Researchers funded by the UK National Institute for Health Research (NIHR) and UK Research and Innovation (UKRI) continue to use the term long COVID because this is used by the public, healthcare professionals, and in literature searches and systematic reviews. Therefore, we use the term long COVID but are explicit that what we report are symptoms 3 months after a positive SARS-CoV-2 test. More than 200 symptoms have been associated with long COVID
5
- Davis HE
- Assaf GS
- McCorkell L
- et al.
Characterizing long COVID in an international cohort: 7 months of symptoms and their impact.
,
6
- Amin-Chowdhury Z
- Ladhani SN
Causation or confounding: why controls are critical for characterizing long COVID.
in individuals symptomatic or asymptomatic with acute SARS-CoV-2 infection and as persistent or intermittent symptoms.
5
- Davis HE
- Assaf GS
- McCorkell L
- et al.
Characterizing long COVID in an international cohort: 7 months of symptoms and their impact.
,
6
- Amin-Chowdhury Z
- Ladhani SN
Causation or confounding: why controls are critical for characterizing long COVID.
Adolescents might have a higher risk
1
- Molteni E
- Sudre CH
- Canas LS
- et al.
Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2.
than young children but it is unclear if long COVID symptoms are related to the viral infection or the effects of lockdown, school closures, and social isolation.
A July, 2021, literature review of long COVID in children and young people identified 21 relevant publications (
appendix pp 16–18, 28–29). These studies included 16 243 children and young people aged 0 to 20 years with follow-up ranging between 28 and 324 days; median follow-up was 125 days (IQR 99–231;
appendix pp 16–18, 28–29). Fourteen (67%) were cohort studies, six (29%) were cross-sectional studies, and one was a case report. Seven of the 21 studies included population-based control groups. Nine (43%) recruited from a mix of hospitalised and non-hospitalised children and young people, eight (38%) recruited from non-hospitalised children and young people, and four (19%) recruited hospitalised children or young people post-discharge. The most common symptoms at 3 months were fatigue, insomnia, anosmia, and headaches. The reported rate of long COVID in children and young people was 1–51%, with smaller studies reporting higher rates. Additionally, a UK survey of self-reported or parent-reported long COVID reported a prevalence of 0·16% in those aged 2–11 years, 0·65% in those aged 12–16 years, and 1·22% in those aged 17–24 years.
7
Office for National Statistics
Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK Statistical bulletins.
The CLoCk study is a national, matched, longitudinal cohort study of children and adolescents in England,
8
- Stephenson T
- Shafran R
- De Stavola B
- et al.
Long COVID and the mental and physical health of children and young people: national matched cohort study protocol (the CLoCk study).
describing the clinical phenotype and rate of post-COVID physical and mental health problems in those with laboratory-confirmed SARS-CoV-2 infection compared with those who test negative for SARS-CoV-2. This paper presents the descriptive results from the study 3 months after PCR testing.
Results
Of 50 846 adolescents who were tested between Jan 1 and March 31, 2021, and were invited to participate, 6804 (13·4%) consented to complete the 3-month questionnaire and constituted the subsample population (
table 1), including 3065 (45·0%) who tested positive for SARS-CoV-2 and 3739 (55·0%) who tested negative (
table 2). A total of 63 adolescents who tested negative reported having had a previous positive SARS-CoV-2 test (before testing) and were excluded. Of those who tested positive, 49 went to hospital with 26 staying overnight. The completed questionnaires were returned at a median of 14·9 weeks (IQR 13·1–18·9) after testing.
Table 1Response rate of participants who completed the 3-month questionnaire
Data are n (%). IMD=Index of Multiple Deprivation.
Table 2Baseline characteristics of all study participants who completed the 3-month questionnaire
Data are n (%). IMD=Index of Multiple Deprivation.
At the time of testing, 1084 (35·4%) of 3065 adolescents who tested positive and 309 (8·3%) of 3739 who tested negative reported having had any symptoms; 936 (30·5%) of those who tested positive and 231 (6·2%) of those who tested negative had at least three symptoms and 726 (23·7%) who tested positive and 143 (3·8%) who tested negative had at least five symptoms. Because differences between adolescents who tested positive and those who tested negative become more striking for multiple symptoms than for a single symptom, we use three or more symptoms and five or more symptoms for illustrative purposes (
table 3). The most common symptoms among adolescents who tested positive were sore throat, headache, tiredness, and loss of smell and among those who tested negative were sore throat, headache, fever, and persistent cough. The prevalence of symptoms varied by SARS-CoV-2 status (eg, headaches were reported by 806 [26·3%] of those who tested positive compared to 178 [4·8%] of those who tested negative). Of note, prevalence of pre-existing morbidity (eg, asthma) were broadly similar in participants positive and negative for SARS-CoV-2 (
appendix p 19).
Table 3Reported symptoms at the time of test, and physical and mental health before test, by SARS-CoV-2 status, overall and stratified by age group
3 months after testing, the presence of physical symptoms had increased in both groups: 2038 (66·5%) of those who tested positive and 1993 (53·3%) of those who tested negative had symptoms of any kind, 928 (30·3%) of those who tested positive and 603 (16·2%) of those who tested negative had at least three symptoms, and 411 (13·4%) of those who tested positive and 238 (6·4%) of those who tested negative had at least five symptoms (
table 4). The most common symptoms among those who tested positive were tiredness, headache, and shortness of breath, and, among those who tested negative, were tiredness, headache, and the unspecified category of other. Again, the prevalence of tiredness and headache was consistently higher in those who tested positive (1196 [39·0%] for tiredness and 710 [23·2%] for headaches) than those who tested negative (911 [24·4%] for tiredness and 530 [14·2%] for headaches). For both the group who tested positive and the group who tested negative, prevalence of most symptoms was higher for adolescents aged 15–17 years than those aged 11–14 years; for example, 818 (44·9%) of those aged 15–17 years who tested positive reported being tired compared with 378 (30·4%) of adolescents aged 11–14 years who tested positive. When we reweighted the percentage of reported symptoms at baseline and at 3 months post-test, broadly similar patterns were observed to those reported above (
appendix pp 19–21). When we compared reasons for testing, the majority of adolescents who tested negative were identified via school surveillance (2658 [71·1%]) versus only 793 (25·9%) of those who tested positive (
appendix p 21). Apart from age, no systematic differences were observed in demographic characteristics across reasons for testing (
appendix p 22).
Table 4Reported symptoms at 3 months by SARS-CoV-2 status, overall and stratified by age group
There was no difference in the distribution of mental health scores (assessed by the SDQ total difficulties scores) and wellbeing (assessed by SWEMWBS) between those who tested positive and those who tested negative for SARS-CoV-2. The SDQ median was 9 (IQR 5–14) for adolescents aged 11–14 years in both the test-positive and test-negative groups and 12 (7–16) for adolescents aged 15–17 years in both test groups. SWEMWBS scores did not vary by age and mean scores were similar among those who tested positive (21·5; SD 4·3) and those who tested negative (21·4; SD 4·3). Mean fatigue scores were not substantially different between those who tested positive (13·3; SD 5·2) and those who tested negative (12·5; SD 5·1), with slightly higher fatigue scores in older participants across both test groups. EQ-5D-Y scores, representing health-related quality of life, showed that adolescents who tested positive in both age groups were more likely to report problems with mobility, doing usual activities, and pain or discomfort than those who tested negative, and younger adolescents who tested positive were more likely to be worried or sad than younger adolescents who tested negative (
appendix p 25). Strikingly, 1251 (40·8%) of participants who tested positive and 1467 (39·2%) who tested negative and felt worried, sad, or unhappy, as indicated on a single item of the EQ-5D-Y.
At baseline, there was no evidence of clustering of physical symptoms in either those who tested positive or those who tested negative. By contrast, there was evidence of clustering of physical symptoms reported at 3 months, with two subgroups emerging for both test groups (
appendix pp 26–27). In each, the largest subgroup (class 1) had very low prevalence of most physical symptoms, and the second subgroup (class 2) was characterised in both test groups by multiple symptoms dominated by tiredness, headache, shortness of breath, and dizziness. We refer to these classes as few and multiple symptoms classes. The estimated probability (risk) of being in the multiple symptom class (class 2) was 29·6% (95% CI 27·4–31·7) for those who tested positive and 19·3% (17·7–21·0) for those who tested negative, and the risk ratio of being in class 2 versus class 1 comparing those who tested positive to those who tested negative was 1·53 (95% CI 1·35–1·70).
For both test groups, those assigned to the multiple symptoms class 2 at 3 months were more likely to be girls, older, and have very poor or poor baseline physical and mental health (
appendix pp 23–24). At 3 months, adolescents assigned to class 2 were more likely to have worse mental health and wellbeing as shown by higher scores on all five items of the EQ-5D-Y scale, generally higher SDQ (total difficulties and each subscale) and CFS scores, and lower SWEMWBS scores (
appendix p 24).
Discussion
Without a definition of long COVID, we elected not to ask about self-reported long COVID. This study describes adolescent-reported symptoms during their acute illness and 3 months after PCR-proven SARS-CoV-2 infection, with a PCR-negative comparison group and standardised mental health, well-being, and fatigue instruments.
Important findings are, first, 3 months after the SARS-CoV-2 test, the presence of physical symptoms was higher than at the time of testing, emphasising the importance of having a comparison group to interpret the findings. Although 1981 (64·6%) of adolescents testing positive reported no symptoms at time of testing (compared to 3430 [91·7%] of adolescents who tested negative), only 1027 (33·5%) of those who tested positive (and 1746 [46·7%] of those who tested negative) reported no symptoms at 3 months. This finding could be due to self-selection, recall bias for symptoms at the time of testing, or returning to school from March, 2021, following national lockdown from January, 2021, with exposure to other infections.
Second, symptoms reported at time of testing did not distinguish those who tested positive (sore throat, headache, tiredness, and loss of smell) from those who tested negative (sore throat, headache, fever, and persistent cough), potentially because national testing was primarily targeted for those with fever, new-onset cough, and loss of taste or smell. However, the two groups could be separated according to the number of symptoms at 3 months, when 928 (30·3%) of participants who tested positive and 603 (16·2%) of participants who tested negative had 3 or more symptoms. Consideration of number of symptoms is particularly important given that 1993 (53·3%) of the participants who tested negative had at least one symptom 3 months after the test. These figures should be interpreted against published prepandemic norms: 255 (30%) of 842 adolescents aged 11–15 years reported fatigue over a 4–6-month prepandemic period;
19
- Rimes KA
- Goodman R
- Hotopf M
- Wessely S
- Meltzer H
- Chalder T
Incidence, prognosis, and risk factors for fatigue and chronic fatigue syndrome in adolescents: a prospective community study.
a cross-sectional survey reported 1587 (19·9%) of 7977 adolescents to have headache, fatigue, or asthma.
20
Office for National Statistics
Mental health of children and young people in Great Britain, 2004.
Third, for test groups, those assigned to the latent class with multiple symptoms at 3 months were more likely to be female, older, and have poorer physical and mental health before COVID-19, suggesting that pre-existing physical and mental health difficulties might influence symptoms at 3 months. Unsurprisingly, regardless of test status, those with multiple physical symptoms at 3 months after the test concurrently had poorer mental health, reflecting the close relationship between physical and mental health.
Fourth, although the prevalence of physical symptoms differed between test groups, mental health, wellbeing, and fatigue scores were similar. However, a large proportion (approximately 40%) in both groups reported feeling worried, sad, or unhappy, consistent with parent-reported surveys of mental health of children and young people during the pandemic.
21
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- Pearcey S
- Skripkauskaite S
- Patalay P
- Waite P
Young people’s mental health during the COVID-19 pandemic.
,
22
- Skripkauskaite S
- Shum A
- Pearcey S
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- Waite P
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Report 08: changes in children’s and young people’s mental health symptoms: March 2020 to January 2021.
The findings emphasise the importance of incorporating a comparator-matched cohort of participants who tested negative and also experienced a pandemic, school closures, and social isolation. Our findings suggest that any definition of long COVID should consider multiple symptoms that affect functioning and recognise different clusters of symptoms.
23
- Whitaker M
- Elliott J
- Chadeau-Hyam M
- et al.
Persistent symptoms following SARS-CoV-2 infection in a random community sample of 508,707 people.
Finally, given the multiple symptoms at 3 months, a multicomponent intervention will be required to manage adolescents with long COVID, building on existing management of symptoms such as chronic fatigue and headaches.
24
- Fisher E
- Law E
- Dudeney J
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- Stewart G
- Eccleston C
Psychological therapies for the management of chronic and recurrent pain in children and adolescents.
The most common symptoms at 3 months among those who tested positive of tiredness, headache, shortness of breath, dizziness, and anosmia are consistent with other studies in young people,
1
- Molteni E
- Sudre CH
- Canas LS
- et al.
Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2.
,
7
Office for National Statistics
Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK Statistical bulletins.
which also identified higher symptom prevalence in girls than boys, adolescents than younger children, and children with long-term conditions than those without.
1
- Molteni E
- Sudre CH
- Canas LS
- et al.
Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2.
We show that mental and physical health symptoms are related. Stress might manifest as somatic symptoms,
25
Concern for Covid-19 cough, fever and impact on mental health. What about risk of Somatic Symptom Disorder?.
and persisting physical symptoms might be associated with depression and anxiety. Family approaches to managing continuing symptoms are key,
26
- O’Connell K
- Berluti K
- Rhoads SA
- Marsh AA
Reduced social distancing early in the COVID-19 pandemic is associated with antisocial behaviors in an online United States sample.
as is the negative effect of protracted medical investigations and treatments.
25
Concern for Covid-19 cough, fever and impact on mental health. What about risk of Somatic Symptom Disorder?.
This study has limitations, including the cross-sectional nature of this initial questionnaire 3 months after testing. The questionnaire will be resent at 6, 12, and 24 months after testing. Although the study design is prospective, the data on symptoms at the time of PCR testing were retrospective and hence prone to recall bias. Some symptoms might have been present before SARS-COV-2 infection. Participants did not report the severity of symptoms and although the number of symptoms could serve as a proxy of overall illness severity, a single severe symptom might be more disabling than several mild symptoms. The EQ-5D-Y is one indicator of severity because it assesses the effect on daily living. It is possible that some participants might have been misdiagnosed as SARS-CoV-2 negative and vice versa. False negatives might be attributable to the timing of the PCR, swab technique, and assay sensitivity, but false-positive PCR results are rare. We could not recruit or match on ethnicity, medical history, or testing location (as not recorded in PHE database at testing) but subsequent self-reported ethnicity was very similar in both test groups and geographical address served as a proxy for socioeconomic status; both are potentially important variables in long COVID.
27
- Patel P
- Hiam L
- Sowemimo A
- Devakumar D
- McKee M
We did not assess physical symptom severity at the time of testing or 3 months after testing. We used established scales to measure mental health,
11
NHS Digital
Mental Health of Children and Young People in England, 2020: wave 1 follow up to the 2017 survey.
wellbeing,
12
Psychometric properties of the strengths and difficulties questionnaire.
,
13
- Tennant R
- Hiller L
- Fishwick R
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and fatigue,
14
- Wille N
- Badia X
- Bonsel G
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but acknowledge the limitations of self-reporting and floor and ceiling effects (ie, if the tests or scales are relatively easy or difficult such that substantial proportions of individuals obtain either maximum or minimum scores and that the true extent of their abilities cannot be determined).
6804 (13·4%) of 50 846 adolescents responded to our survey, which is comparable to other COVID-19 related studies. The UK Office for National Statistics (ONS) studies had an enrolment rate of 12% between July, 2020, and November, 2021, when sampling randomly.
28
Office for National Statistics
Coronavirus (COVID-19) Infection Survey: technical data.
The REACT 2 study had a 30% response rate for adults randomly selected from the NHS patient lists despite being offered a free antibody test delivered to their home.
29
- Ward H
- Cooke GS
- Atchison C
- et al.
Prevalence of antibody positivity to SARS-CoV-2 following the first peak of infection in England: serial cross-sectional studies of 365 000 adults.
We cannot deduce how representative the 6804 respondents were of the 23 048 young people who tested positive and the 27 798 who tested negative that we approached, other than in terms of age, sex, geographical region, and IMD quintiles, because only NHS number, name, age, sex, and postcode were recorded in the PHE database. We can consider a sensitivity analysis of two scenarios. Between Sept 1, 2020, and March 31, 2021, 234 803 people aged 11–17 years tested positive for SARS-CoV-2. If our 13% of respondents are representative of all people aged 11–17 years who tested positive, then across England 70 441 adolescents would have at least three physical symptoms, 3 or more months after a positive test and 30 524 would have at least five physical symptoms. How many of these are attributable to SARS-CoV-2 infection over and above the background symptom levels in adolescents who tested negative? The excess is 32 872 (1 in 7, or 14% of 234 803) with three or more physical symptoms and 16 436 (1 in 14, or 7%) with five or more physical symptoms.
The ONS estimated the percentage of young people in England with self-reported long COVID of any duration as 0·51% for those aged 12–16 years and 1·21% for those aged 17–24 years, equating to 31 080 aged 11–17 years across England.
7
Office for National Statistics
Prevalence of ongoing symptoms following coronavirus (COVID-19) infection in the UK Statistical bulletins.
Despite differences in definitions and methodology, this figure is very similar to our figure of 32 872 young people aged 11–17 years with three or more persisting physical symptoms attributable to SARS-CoV-2.
However, if our 13% of responders are entirely unrepresentative and the 87% of non-responders had completely recovered, then 9157 of the 234 803 adolescents aged 11–17 years who tested positive for SARS-CoV-2 would have at least three physical symptoms 3 or more months after a positive test and 3968 would have five or more physical symptoms. The number attributable to SARS-CoV-2 infection over and above the background symptom levels in adolescents aged 11–17 years who test negative is 4273 (1 in 50, or 1·8% of 234 803) with three or more physical symptoms and 2137 with five or more physical symptoms (1 in 100, or 0·9% of 234 803). Both scenarios indicate the additional risk of multiple symptoms at least 3 months after a SARS-CoV-2 positive test is much less than the 51% feared, on the basis of some previous studies (
appendix pp 16–18).
Another limitation is that we did not assess whether symptoms were intermittent or continuous for the entire 3 months. Finally, the experiences of adolescents were likely to vary depending on whether they were in lockdown or attending school at the time. At the time of PCR testing schools were closed, but at 3 months after testing, schools had reopened albeit with social distancing, repeated testing, and restriction of activities.
Our findings reflect a period when the alpha variant was predominant in the UK. The rate of continuing post-COVID symptoms might change with different variants. In summary, our research shows the importance of having a test-negative comparison group to interpret findings, that it is essential to consider multiple symptoms in the phenotype of long COVID, that mental and physical health symptoms should both be considered, and that adolescents with PCR-proven SARS-CoV-2 had a higher frequency of any symptoms, and multiple physical symptoms, 3 months after testing than adolescents who tested negative.
TS conceived the idea for the study and submitted the successful grant application. TS and RSh decided to submit the manuscript. TS, SMPP, RSh, and BLdS drafted the manuscript. SMPP did the statistical analyses for the manuscript. SMPP, BLdS, and RSi accessed and verified the data. RSh provided ideas on mental health to the original grant application and submitted the ethics and research and development applications. BLdS provided statistical input to the design and did the analyses, including sample size calculations. NR supported the drafting of the manuscript and the statistical analyses. KM adapted the questionnaire for the online SNAP survey platform. RSi designed the participant sampling and dataflow. MZ undertook a separate pilot study that informed the CLoCk consent process and the online questionnaire. LO’M contributed to the scoping review of the literature. TC and IH contributed to the work on psychiatric liaison. EC contributed to the work on chronic fatigue and contributed to the manuscript. EC, TJF, AH, IH, OS, and EW reviewed the manuscript. TJF contributed to the work on epidemiology, schools, and mental health. AH contributed to the work on primary care. OS and EW contributed to the work on infection and designed the elements of the ISARIC Paediatric COVID-19 follow-up questionnaire that were incorporated into the online questionnaire used in this study to which all the CLoCk Consortium members contributed. SNL developed the study methodology, operationalised the regulatory and recruitment ideas for the study, and revised the manuscript. All members of the CLoCk Consortium made contributions to the conception or design of the work and were involved in drafting both the funding application and this manuscript. All authors had full access to all the data in the study, had final responsibility for the decision to submit for publication, and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
