COVID-19 Schools Infection Survey, England: mental health and long COVID, November to December 2021

• Since March 2020, 1.0% of primary school-aged pupils and 2.7% of secondary school-aged pupils met the Delphi criteria for having experienced long COVID lasting at least 12 weeks.

• "Loss of taste or smell" was the only symptom group where the prevalence was significantly higher for those who had received a positive coronavirus (COVID-19) test since March 2020 than those who hadn't, for both primary and secondary school-aged pupils aged under 16 years.

• Both primary and secondary school pupils who tested positive for COVID-19 showed no significant difference in the number presenting with a "probable mental disorder" compared with those without a positive test.

• Primary school pupils with long COVID (under the Delphi criteria) were significantly more likely to have a probable mental disorder (30.0%) than those without long COVID (7.7%); the trend was similar for secondary school pupils (22.6% compared with 13.6%), but this is not statistically significant.

To estimate the prevalence of long COVID, we used the CLoCK Delphi consensus criteria (PDF, 588KB) for non-hospitalised children and young people with long COVID (the CLoCK study) for our calculations. This defines long COVID as being present if all the following conditions are met.

• A positive test for coronavirus (COVID-19) infection.

• The presence of symptoms continuously over a 12-week period or longer.

• Everyday life is affected by these symptoms.

Parents responded on behalf of pupils in school Years Reception to Year 6 and pupils in school Years 7 to 13 responded on behalf of themselves. In addition, for pupils in school Years 7 to 11, parents responded about specific symptoms on their behalf because of the difficulty in children under 16 years recalling specific symptoms since the start of the pandemic.

Long COVID among primary school-aged pupils

Around 1 in 100 (1.0%) pupils in primary schools fulfilled all the criteria for long COVID at some point since March 2020 (Figure 1).

We asked parents about any of 28 symptoms their children had displayed for a period of 12 weeks or more since March 2020. This was asked of everyone, not just those reporting to have had COVID-19. We have compared two groups - those that had a positive COVID-19 test at any time since March 2020, and those without a positive test (this can include people who believe they have had COVID-19 but never got tested, and those who do not believe they have had COVID-19).

Nearly half (47.5%) of primary school pupils with a positive COVID-19 test since March 2020 were reported by their parents to have experienced at least one recurring symptom (Figure 2). This was 46.6% for those without a positive test.

Over a quarter (26.0%) of primary school pupils with a positive test and 20.7% of those without a positive test experienced three or more symptoms.

“Loss of taste or smell” was the only symptom group where the prevalence was significantly higher for those who had received a positive COVID-19 test (5.2%) than those who hadn’t (0.4%). Other symptom groups showed no significant difference by positive test status.

For primary school pupils, 25.3% of parents reported that they believed their child had had COVID-19 since March 2020 (including those that had a positive COVID-19 test and those that hadn't). Of those, 6.3% experienced ongoing symptoms for 12 or more weeks.

Among those pupils who had experienced ongoing symptoms, nearly half (49.2%) of primary school-aged pupils were reported as having their emotional well-being "affected a little" or "a lot" by their symptoms. Over a third (37.1%) were reported as having their ability to stay physically active affected and just over a third (34.0%) as having their ability to learn affected. Among the same pupils, almost half (49.1%) said they were now "fully recovered" and a further 27.6% were "greatly" or "somewhat improved". Nearly a fifth (17.7%) said their symptoms "vary day by day".

Long COVID among secondary school-aged pupils

2.7% of pupils in secondary schools fulfilled all the criteria for long COVID (as defined by CLoCK Delphi consensus) at some point since March 2020. This was 2.5% for pupils in school Years 7 to 11 (aged 11 to 16 years) and 4.4% for pupils in school Years 12 to 13 (aged 16 to 18 years).

57.6% of Year 7 to 11 pupils with a positive COVID-19 test were reported as having experienced at least one recurring symptom for 12 weeks or more since March 2020 (Figure 5). Half (49.5%) of those without a positive test experienced at least one recurring symptom. A third (32.5%) of Year 7 to 11 pupils with a positive test and 26.9% of those without a positive test experienced three or more recurring symptoms.

“Loss of taste or smell” was the only symptom group where the prevalence was significantly higher for those who had received a positive COVID-19 test (16.6%) than those who hadn’t (0.4%). Other symptom groups showed no significant difference by positive test status.

Of all Year 7 to 11 pupils, 35.5% reported that they believed they had previously had COVID-19 since March 2020 (including those that had a positive COVID-19 test and those that hadn’t). Of those who believed they had COVID-19, 11.3% of pupils reported that they had experienced ongoing symptoms. Of these pupils, 51.7% reported their ability to stay physically active was affected a little or a lot by their symptoms and 47.5% said their emotional well-being was affected a little or a lot. Of those experiencing ongoing symptoms, 17.8% said they were “fully recovered” from their symptoms, a further 55.6% said they were “greatly improved” or “somewhat improved” and 20.3% said they “vary day by day”.

This analysis relates to the mental health of the pupil population. The measurement approach taken by the COVID-19 Schools Infection Survey (SIS) is to use parent-reported measures for primary school-aged pupils and self-reported measures for secondary school-aged pupils. The Strengths and Difficulties Questionnaire is used to define "probable", "possible" and "unlikely" mental disorders using a scoring algorithm. More detail can be found in the Glossary.

Primary school-aged pupils' mental health

We found that 8.0% of primary school-aged pupils had a probable mental disorder and a further 7.6% of pupils had a possible mental disorder. Significantly more primary school-aged pupils had a probable hyperactivity disorder (5.9%) than a probable emotional disorder (1.7%) or a probable conduct disorder (1.9%).

Around 1 in 10 male primary school-aged pupils had a probable mental disorder, which was significantly higher than female primary school-aged pupils (5.8%). Primary school-aged pupils with a long-term health condition were significantly more likely to have a probable mental disorder (21.5%) than those without (6.4%). Further breakdowns are available in our accompanying dataset.

Secondary school and sixth form aged pupils' mental health

We found 13.8% of pupils of secondary school age (11 to 18 years) had a probable mental disorder, this was significantly higher for girls (18.9%) than boys (8.8%). A further 12.0% of pupils had a possible mental disorder. Probable hyperactivity disorders had the highest prevalence (9.4%), significantly higher than probable emotional disorder prevalence (4.1%) and probable conduct disorder prevalence (1.9%). Significantly more secondary school pupils eligible for free school meals had a probable mental health disorder compared with those who were not eligible (28.3% compared with 12.4%).

Long COVID and mental health

For primary school pupils, 11.1% of those who received a positive COVID-19 test had a probable mental disorder and 7.2% of those who hadn't received a positive test had a probable mental disorder. For secondary school pupils (school Years 7 to 13), 13.9% of those who received a positive COVID-19 test had a probable mental disorder and 13.6% of those who hadn't received a positive test had a probable mental disorder; these differences were not significant.

Primary school pupils with long COVID were significantly more likely to have at least one probable mental disorder (30.0%) than those without long COVID (7.7%).

For secondary school pupils, 22.6% of those who had experienced long COVID had a probable mental health disorder, compared with 13.6% of pupils who had not. These differences were not significant.

This section contains analysis of the headteacher survey. More information on the collection of data can be found in the Measuring the data section.

Over half (64%) of headteachers said some or all of their staff had received additional training on pupil mental health since September. This was 58% for primary schools and 77% for secondary schools.

Over four-fifths (87%) of headteachers said that their school had a designated lead for pupils’ mental health. Of those with a designated lead, 95% said they felt very or fairly confident that their school was able to implement the activities needed to develop a whole-school approach to mental health. Of the remaining 5%, reasons for not feeling confident were because of lack of time and staff resource pressures.

The Coronavirus (COVID-19) Schools Infection Survey analysis was produced by the Office for National Statistics (ONS) in collaboration with our research partners at the London School of Hygiene and Tropical Medicine and UK Health Security Agency.

Primary school pupils

Primary school pupils are those in school Years Reception to Year 6. These school year groups cover pupils aged 4 to 11 years.

Secondary school pupils

Secondary school pupils are those in school Years 7 to 13. These school year groups cover pupils aged 11 to 18 years.

Long COVID

The term "Long COVID" is generally used to describe the persistence of symptoms, long after you would usually expect them to have resolved, after coronavirus (COVID-19) infection, which can't be explained by another cause.

Delphi consensus on long COVID

The Delphi consensus approach is a well-established, systematic and iterative method that relies on a panel of experts to move towards agreement. Researchers working on the non-hospitalised children and young people with long COVID (CLoCK) study, funded by UK Research and Innovation and the National Institute for Health Research (NIHR), participated in the Delphi approach and agreed that Long COVID could be defined by the presence of all the following:

• a positive test for COVID-19 infection

• the presence of symptoms continuously over a 12-week period or longer

• everyday life is affected by these symptoms

This is a working definition for research purposes, rather than a clinical definition for diagnosing long COVID, such as those published by the National Institute for Health and Care Excellence (NICE) and the World Health Organisation (WHO).

Definitions of long COVID can vary between studies and articles. The Office for National Statistics prevalence of ongoing symptoms analysis uses different criteria, namely people who had a confirmed or suspected COVID-19 infection and responded positively to the survey question “Would you describe yourself as having ‘long COVID’, that is, you are still experiencing symptoms more than 4 weeks after you first had COVID-19, that are not explained by something else?”.

Symptom groupings

The list of COVID-19 symptoms has been grouped following an approach taken by the Patient-Led Research Collaborative. 

Head, ears, eyes, nose and throat symptoms

• Lost or husky voice.

• Sore throat.

• Sore or uncomfortable eyes.

• Earache or ringing in ears.

Cardiovascular symptoms

• Chest pain or tightness.

• Palpitations (feeling like your heart is beating heavily or racing).

Dermatologic

• Raised, red, itchy bumps on skin or swelling of the face or lips.

• Red or purple blisters on your feet or toes.

• Prickling, tingling or burning sensations in skin.

Gastrointestinal

• Diarrhoea.

• Not feeling hungry nor wanting to eat.

• Feeling or being sick.

• Stomach pain.

Mood

• Worry or anxiety.

• Low mood or not enjoying anything.

Musculoskeletal

• Strong aches or pains in muscles or joints.

Cognitive disturbance

• Feeling lightheaded or disorientated.

• Feeling dizzy.

• Trouble sleeping.

• Headache.

• Memory loss or confusion.

• Difficulty concentrating.

Pulmonary

• Cough.

• Feeling short of breath.

Systemic

• Fever or high temperature.

• Chills or shivers.

• Weakness or tiredness.

Loss of smell or taste

• Loss of smell or taste.

Strengths and Difficulties Questionnaire (SDQ)

SDQ is a brief behavioural screening questionnaire about 3 to 16-year-olds. It exists in several versions to meet the needs of researchers, clinicians and educationalists. The questionnaire asks about 25 attributes, some positive and others negative. These 25 items are divided between 5 scales:

• emotional symptoms (5 items)

• conduct problems (5 items)

• hyperactivity or inattention (5 items)

• peer relationship problems (5 items)

• prosocial behaviour (5 items)

The SDQ also includes an impact supplement which asks whether the respondent considers the child or young person to have difficulties, how long they have been present, and the extent to which they cause distress and impairment in functioning in everyday life.

Responses provided in the SDQ were combined using a diagnostic algorithm to indicate whether each child was unlikely, possibly or probably demonstrating a mental health condition in the following domains: emotional, behaviour and hyperactivity disorders. This algorithm combines data from all available informants and a disorder is considered probably present if the scores on the relevant symptom indicate the child is above the 95th percentile and the impact score is two or above according to either informant for emotional difficulties and conduct problems, or two informants if available for hyperactivity. A disorder is considered unlikely if the scores for conduct and emotion were three or below from all informants, and hyperactivity was five or below, plus impact scores were zero. A disorder was considered possible with intermediate scores. More detail on how the algorithm works can be found on the SDQ website.

For the Schools Infection Survey (SIS), we have adapted this methodology in light of only obtaining information from the pupil questionnaire for those aged 11 to 16 years, and only parent questionnaire information for those aged 4 to 11 years. The limitation of our approach is that it is not exactly comparable with other published mental health results, but it provides a measure against a validated methodology.

Data presented in this bulletin are from Round 1 of the coronavirus (COVID-19) Schools Infection Survey (SIS) during the academic year 2021 to 2022.

Data from the parent and pupil questionnaires are weighted to population totals for pupils in state-funded education in England. Headteacher questionnaire data are unweighted because of small sample sizes.

Our methodology article provides further information about response rates, survey design, how we process data and estimation methods.

Reference period

Coverage dates for each survey are:

• parent - 22 November to 15 December 2021

• pupil - 11 November to 15 December 2021

• headteacher - 25 November to 15 December 2021

Response rates

134 schools were registered to the study and been invited to complete the headteacher questionnaire, with 107 responding (80% response rate).

The parents of 4,870 pupils were invited to complete the parent questionnaire; 3,375 parents responded, (on behalf of 4,128 children, as each parent can respond on behalf of multiple children). This gives an 85% response rate.

3,304 pupils were invited to complete the pupil questionnaire and 2,045 responded (62% response rate).

Comparison with other Office for National Statistics (ONS) estimates of long COVID prevalence

The long COVID prevalence estimates in the School Infection Survey are higher than those reported from the COVID-19 Infection Survey (CIS): 0.54% and 1.87% of children aged 2 to 11 years and 12 to 16 years, respectively, reported long COVID symptoms during the four weeks to 2 January 2022.

The estimates in this release relate to period prevalence (children who fulfilled the Delphi long COVID criteria at any time between 1 March 2020 and 15 December 2022, including those whose symptoms had resolved before the end of the period) whereas those from the CIS relate to point-in-time prevalence (capturing only children who currently have symptoms).

The definition of long COVID in the CIS does not include the criteria of previously testing positive for COVID-19 and is based on a 4- rather than a 12-week threshold of persistent symptoms.

A robust sampling and weighting process has been used to ensure data are representative of the pupil population in state-funded schools in England.

All participation has been invited on a voluntary basis. This means there could be some self-selection bias to those who volunteered to participate. Widely used methods are adopted for the surveys' sampling and weighting strategies to limit the impact of bias, but estimation methods can contribute to the level of uncertainty in the data. Bias may be introduced if non-response is related to long COVID, for example participants being more willing, or less able, to continue in the study because of their symptoms.

The sample size is small, meaning that detailed analyses for sub-groups are not possible. Comparisons between groups must be done with caution as estimates are provided from a sample survey; as such, confidence intervals are included in the datasets to present the sampling variability.

Our analysis of those with a positive test will exclude some pupils such as those infected before the introduction of mass community testing around June 2020.