Vaccines for COVID-19: learning from ten phase II trials to inform clinical and public health vaccination programmes.

Public health professionals and clinicians, in many countries, are immersed in the ongoing and upcoming vaccination programmes for COVID-19. Published information from vaccine trials is complex. There are important and helpful insights about the nature of the available and forthcoming vaccines, immune responses and side-effects from phase II trials. We have systematically summarised information from 10 such trials on the nature of the vaccines, exclusions from the trials, immunological effects and side-effects. Some important information within these trial reports is not available in the phase III trial articles, so a complete picture requires examination of phase II and phase III trials for each vaccine. We recommend our systematic approach for the examination of other upcoming COVID-19 vaccine phase II and III trials.

Use of a meningococcal group B vaccine (4CMenB) in populations at high risk of gonorrhoea in the UK.

The meningococcal group B vaccine, 4CMenB, is a broad-spectrum, recombinant protein vaccine that is licensed for protection against meningococcal group B disease in children and adults. Over the past decade, several observational studies supported by laboratory studies have reported protection by 4CMenB against gonorrhoea, a sexually transmitted infection caused by Neisseria gonorrhoeae. Gonorrhoea is a major global public health problem, with rising numbers of diagnoses and increasing resistance to multiple antibiotics. In England, more than 82 000 cases of gonorrhoea were diagnosed in 2022, with nearly half of the cases diagnosed among gay, bisexual, and other men who have sex with men. There are currently no licensed vaccines against gonorrhoea but 4CMenB is estimated to provide 33-47% protection against gonorrhoea. On Nov 10, 2023, the UK Joint Scientific Committee on Vaccination and Immunisation agreed that a targeted programme should be initiated using 4CMenB to prevent gonorrhoea among individuals at higher risk of infection attending sexual health services in the UK. This decision was made after reviewing evidence from retrospective and prospective observational studies, laboratory and clinical data, national surveillance reports, and health economic analyses. In this Review, we summarise the epidemiology of invasive meningococcal disease and gonorrhoea in England, the evidence supporting the use of 4CMenB for protection against gonorrhoea, and the data needed to inform long-term programme planning and extension to the wider population.

Emergency obstetric referral in rural Sierra Leone: what can motorbike ambulances contribute? A mixed-methods study.

Giving birth remains a dangerous endeavour for many of the world's women. Progress to improve this has been slow in sub-Saharan Africa. The second delay, where transport infrastructure is key in allowing a woman to reach care, has been a relatively neglected field of study. Six eRanger motorbike ambulances, specifically engineered for use on poor roads in resource-poor situations were provided in 2006 as part of an emergency referral system in rural Sierra Leone. The aim of this study was to evaluate the implementation of this referral system in terms of its use, acceptability and accessibility. Data were collected from usage records, and a series of semi-structured interviews and focus groups conducted to provide deeper understanding of the service. A total of 130 records of patients being transported to a health facility were found, 1/3 of which were for obstetric cases. The ambulance is being used regularly to transport patients to a health care facility. It is well known to the communities, is acceptable and accessible, and is valued by those it serves. District-wide traditional birth attendant training and the sensitisation activities provided a foundation for the introduction of the ambulance service, creating a high level of awareness of the service and its importance, particularly for women in labour. Motorbike ambulances are suited to remote areas and can function on poor roads inaccessible to other vehicles.

Parental perspectives on emergency health service use during the first wave of the COVID-19 pandemic in the United Kingdom: A qualitative study.

UK 'Lockdown' measures introduced in March 2020 aimed to mitigate the spread of COVID-19. Although seeking healthcare was still permitted within restrictions, paediatric emergency department attendances reduced dramatically and led to concern over risks caused by delayed presentation. Our aim was to gain insight into healthcare decisions faced by parents during the first wave of the COVID-19 pandemic and to understand if use of urgent healthcare, self-care, and information needs differed during lockdown as well as how parents perceived risks of COVID-19. We undertook qualitative telephone interviews with a purposive sample of parents living in the North East of England recruited through online advertising. We used a semi-structured interview schedule to explore past and current healthcare use, perceptions of risk and the impact of the pandemic on healthcare decisions. Interviews were transcribed and analysed using Thematic Analysis. Three major themes were identified which concerned (i) how parents made sense of risks posed to, and by their children, (ii) understanding information regarding health services and (iii) attempting to make the right decision. These themes contribute to the understanding of the initial impact of COVID-19 and associated restrictions on parental decisions about urgent healthcare for children. These findings are important to consider when planning for potential future public health emergencies but also in the wider context of encouraging appropriate use of urgent healthcare.

Parental experiences of childcare in an informal urban settlement: qualitative interview findings from the Nairobi Early Childcare in Slums (NECS) project.

OBJECTIVES: To gain an in-depth understanding of parent/carers' perspectives on, and decision-making about, early childhood care in general, and paid childcare specifically, in informal settlements in Nairobi. DESIGN: In-depth telephone interviews, conducted using a topic guide, were analysed through a combination of deductive and inductive thematic analysis and regular reflexivity meetings. We explored parents' childcare needs and experiences over time, and their perspectives on the provision of paid childcare in the slums. SETTING: Three informal settlements or slums in Nairobi: Kibera; Kawangware; and Mukuru-Viwandani. PARTICIPANTS: A purposively selected sample of 21 parental and non-parental carers of children aged under 5 years who were currently living in three Nairobi slums, including men and women, and users and non-users of paid childcare. RESULTS: Childcare is complex, with a plurality of approaches being used. Common strategies include family member provided care (often but not exclusively by mothers, at home or at a place of work), paid childcare and informal or ad hoc arrangements with neighbours. Childcare decision-making in these settings is constrained by economics and the broader context of living in the slum. Paid childcare is frequently used, but is widely understood to be lacking in quality, especially for the poorest. Quality of childcare is understood to comprise a combination of structural factors, such as the physical space, play and learning resources and processes such as interactions between the care provider and children or parents. CONCLUSIONS: These findings suggest a need, and opportunity, to improve early childhood care in slums. Understanding parental perspectives on both the deficiencies and valued features of childcare is likely to be vital to informing efforts to improve childcare in these settings.

Parental experiences of the impacts of Covid-19 on the care of young children; qualitative interview findings from the Nairobi Early Childcare in Slums (NECS) project.

INTRODUCTION: The Covid-19 pandemic, and societal attempts to control it, have touched almost every aspect of people's lives around the world, albeit in unequal ways. In particular, there is considerable concern about the way that stringent 'lockdowns', as implemented in Kenya and many other countries, affected young children, especially those living in informal settlements. However, to date, there has been little research attempting to unpack and understand how the pandemic has impacted on the care of young children. METHODS: In-depth telephone interviews were conducted with 21 parents/carers of children aged under five years living in three Nairobi slums between May and September 2021 exploring the ways in which Covid-19, and policies to control the pandemic, impacted on their household and the care of their child/children. RESULTS: The impacts of Covid-19 control measures on the care of children have been widely felt, deep and multiple. The impact of economic hardship has been significant, reportedly undermining food security and access to services including healthcare and childcare. Respondents reported an associated increase in domestic and community violence. Many people relied on help from others; this was most commonly reported to be in the form of variable levels of flexibility from landlords and help from other community members. No direct harms from Covid-19 disease were reported by respondents. CONCLUSION: The impacts of Covid-19 control measures on the care of young children in informal settlements have been indirect but dramatic. Given the breadth and depth of these reported impacts, and the particular vulnerability of young children, deeper consideration ought to inform decisions about approaches to implementation of stringent disease control measures in future. In addition, these findings imply a need for both short- and long-term policy responses to ameliorate the impacts described.

Effect of the SPRING home visits intervention on early child development and growth in rural India and Pakistan: parallel cluster randomised controlled trials.

Introduction: Almost 250 million children fail to achieve their full growth or developmental potential, trapping them in a cycle of continuing disadvantage. Strong evidence exists that parent-focussed face to face interventions can improve developmental outcomes; the challenge is delivering these on a wide scale. SPRING (Sustainable Programme Incorporating Nutrition and Games) aimed to address this by developing a feasible affordable programme of monthly home visits by community-based workers (CWs) and testing two different delivery models at scale in a programmatic setting. In Pakistan, SPRING was embedded into existing monthly home visits of Lady Health Workers (LHWs). In India, it was delivered by a civil society/non-governmental organisation (CSO/NGO) that trained a new cadre of CWs. Methods: The SPRING interventions were evaluated through parallel cluster randomised trials. In Pakistan, clusters were 20 Union Councils (UCs), and in India, the catchment areas of 24 health sub-centres. Trial participants were mother-baby dyads of live born babies recruited through surveillance systems of 2 monthly home visits. Primary outcomes were BSID-III composite scores for psychomotor, cognitive and language development plus height for age z-score (HAZ), assessed at 18 months of age. Analyses were by intention to treat. Results: 1,443 children in India were assessed at age 18 months and 1,016 in Pakistan. There was no impact in either setting on ECD outcomes or growth. The percentage of children in the SPRING intervention group who were receiving diets at 12 months of age that met the WHO minimum acceptable criteria was 35% higher in India (95% CI: 4-75%, p = 0.023) and 45% higher in Pakistan (95% CI: 15-83%, p = 0.002) compared to children in the control groups. Discussion: The lack of impact is explained by shortcomings in implementation factors. Important lessons were learnt. Integrating additional tasks into the already overloaded workload of CWs is unlikely to be successful without additional resources and re-organisation of their goals to include the new tasks. The NGO model is the most likely for scale-up as few countries have established infrastructures like the LHW programme. It will require careful attention to the establishment of strong administrative and management systems to support its implementation.

Qualitative analysis of the impact of the SARS-CoV-2 pandemic response on paediatric health services in North of Scotland and North of England.

OBJECTIVE: To capture the extent and impact of changes in the delivery of child health services in the UK, resulting from the SARS-CoV-2 pandemic response, from the perspectives of a range of child healthcare providers. SETTING: National Health Service commissioned/delivered healthcare services in two regional settings in the UK: North of Scotland (NOS) and North East and North Cumbria (NENC) in England. PARTICIPANTS: Purposive sample of 39 child healthcare professionals including paediatricians, community/specialist nurses, allied health professionals and mental health professionals, from across the two regions (22 in NOS, 17 in NENC). METHODS: Semistructured qualitative interviews conducted via telephone between June and October 2020, fully transcribed and analysed in NVivo V.11 using thematic analysis. RESULTS: Extensive changes across a range of paediatric services were rapidly implemented to support the pandemic response and ongoing healthcare delivery. New ways of working emerged, principally to control the spread of the virus. Keeping users and their families out of hospital was an urgent driver for change. The changes had considerable impact on the health and well-being of staff with many experiencing radical changes to their working conditions and roles. However, there were some positive changes noted: some practitioners felt empowered and listened to by decision makers; some of the usual bureaucratic barriers to change were lifted; staff saw improved collaboration and joint working across the system; and some new ways of working were seen to be more efficient. Interviewees perceived the implications for children and their families to be profound, particularly with regard to self-care, relationships with practitioners and timely access to services. CONCLUSIONS: Despite the challenges experienced by staff, the pandemic provided an opportunity for positive, lasting change. It is vital to capitalise on this opportunity to benefit patient outcomes and to 'build back' services in a more sustainable way.

The effect of cumulative early life adversities, and their differential mediation through hair cortisol levels, on childhood growth and cognition: Three-year follow-up of a birth cohort in rural India.

Background: Early adversities negatively impact children's growth and development, putatively mediated by chronic physiological stress resulting from these adverse experiences. We aimed to estimate the associations between prospectively measured cumulative early adversities with growth and cognition outcomes in rural Indian preschool children and to explore if hair cortisol concentration (HCC), a measure of chronic physiological stress, mediated the above association. Methods: Participants were recruited from the SPRING cRCT in rural Haryana, India. Adversities experienced through pregnancy and the first year of life were measured in 1304 children at 12-months. HCC was measured at 12-months in 845 of them. Outcome measures were height-for-age-z-score (HAZ), weight-for-age-z-score (WAZ) and cognition, measured in 1124 children followed up at 3-years. Cognition was measured using a validated tablet-based gamified tool named DEEP. Results: Cumulative adversities at 12-months were inversely associated with all outcomes measures at 3-years. Each unit increase in adversity score led to a decrease of 0·08 units [95% confidence interval (CI):-0·11,-0·06] in DEEP-z-score; 0·12 units [-0·14,-0·09] in HAZ and 0·11 units [-0·13,-0·09] in WAZ. 12-month HCC was inversely associated with DEEP-z-score (-0·09 [-0·16,-0·01]) and HAZ (-0·12 [-0·20,-0·04]), but the association with WAZ was not significant (p = 0·142). HCC marginally mediated the association between cumulative adversities and HAZ (proportion mediated = 0·06, p = 0·014). No evidence of mediation was found for the cognition outcome. Conclusions: Cumulative early adversities and HCC measured at 12-months have persistent negative effects on child growth and cognition at 3-years. The association between adversities and these two child outcomes were differentially mediated by HCC, with no evidence of mediation observed for the cognitive outcome. Future studies should focus on other stress biomarkers, and alternate pathways such as the immune, inflammation and cellular ageing pathways, to unpack key mechanisms underlying the established relationship between early adversities and poor child outcomes.

Post-vaccination infection rates and modification of COVID-19 symptoms in vaccinated UK school-aged children and adolescents: A prospective longitudinal cohort study.

Background: We aimed to explore the effectiveness of one-dose BNT162b2 vaccination upon SARS-CoV-2 infection, its effect on COVID-19 presentation, and post-vaccination symptoms in children and adolescents (CA) in the UK during periods of Delta and Omicron variant predominance. Methods: In this prospective longitudinal cohort study, we analysed data from 115,775 CA aged 12-17 years, proxy-reported through the Covid Symptom Study (CSS) smartphone application. We calculated post-vaccination infection risk after one dose of BNT162b2, and described the illness profile of CA with post-vaccination SARS-CoV-2 infection, compared to unvaccinated CA, and post-vaccination side-effects. Findings: Between August 5, 2021 and February 14, 2022, 25,971 UK CA aged 12-17 years received one dose of BNT162b2 vaccine. The probability of testing positive for infection diverged soon after vaccination, and was lower in CA with prior SARS-CoV-2 infection. Vaccination reduced proxy-reported infection risk (-80·4% (95% CI -0·82 -0·78) and -53·7% (95% CI -0·62 -0·43) at 14-30 days with Delta and Omicron variants respectively, and -61·5% (95% CI -0·74 -0·44) and -63·7% (95% CI -0·68 -0.59) after 61-90 days). Vaccinated CA who contracted SARS-CoV-2 during the Delta period had milder disease than unvaccinated CA; during the Omicron period this was only evident in children aged 12-15 years. Overall disease profile was similar in both vaccinated and unvaccinated CA. Post-vaccination local side-effects were common, systemic side-effects were uncommon, and both resolved within few days (3 days in most cases). Interpretation: One dose of BNT162b2 vaccine reduced risk of SARS-CoV-2 infection for at least 90 days in CA aged 12-17 years. Vaccine protection varied for SARS-CoV-2 variant type (lower for Omicron than Delta variant), and was enhanced by pre-vaccination SARS-CoV-2 infection. Severity of COVID-19 presentation after vaccination was generally milder, although unvaccinated CA also had generally mild disease. Overall, vaccination was well-tolerated. Funding: UK Government Department of Health and Social Care, Chronic Disease Research Foundation, The Wellcome Trust, UK Engineering and Physical Sciences Research Council, UK Research and Innovation London Medical Imaging & Artificial Intelligence Centre for Value Based Healthcare, UK National Institute for Health Research, UK Medical Research Council, British Heart Foundation and Alzheimer's Society, and ZOE Limited.

Illness Characteristics of COVID-19 in Children Infected with the SARS-CoV-2 Delta Variant.

BACKGROUND: The Delta (B.1.617.2) SARS-CoV-2 variant was the predominant UK circulating strain between May and November 2021. We investigated whether COVID-19 from Delta infection differed from infection with previous variants in children. METHODS: Through the prospective COVID Symptom Study, 109,626 UK school-aged children were proxy-reported between 28 December 2020 and 8 July 2021. We selected all symptomatic children who tested positive for SARS-CoV-2 and were proxy-reported at least weekly, within two timeframes: 28 December 2020 to 6 May 2021 (Alpha (B.1.1.7), the main UK circulating variant) and 26 May to 8 July 2021 (Delta, the main UK circulating variant), with all children unvaccinated (as per national policy at the time). We assessed illness profiles (symptom prevalence, duration, and burden), hospital presentation, and presence of long (≥28 day) illness, and calculated odds ratios for symptoms presenting within the first 28 days of illness. RESULTS: 694 (276 younger (5-11 years), 418 older (12-17 years)) symptomatic children tested positive for SARS-CoV-2 with Alpha infection and 706 (227 younger and 479 older) children with Delta infection. Median illness duration was short with either variant (overall cohort: 5 days (IQR 2-9.75) with Alpha, 5 days (IQR 2-9) with Delta). The seven most prevalent symptoms were common to both variants. Symptom burden over the first 28 days was slightly greater with Delta compared with Alpha infection (in younger children, 3 (IQR 2-5) symptoms with Alpha, 4 (IQR 2-7) with Delta; in older children, 5 (IQR 3-8) symptoms with Alpha, 6 (IQR 3-9) with Delta infection ). The odds of presenting several symptoms were higher with Delta than Alpha infection, including headache and fever. Few children presented to hospital, and long illness duration was uncommon, with either variant. CONCLUSIONS: COVID-19 in UK school-aged children due to SARS-CoV-2 Delta strain B.1.617.2 resembles illness due to the Alpha variant B.1.1.7., with short duration and similar symptom burden.

Making pre-school children wear masks is bad public health.

Children are not small adults. This is a critical point that many pediatricians and other child health professionals get bored of saying, yet it does seem to need repeating. While children have the lowest risk from COVID-19 directly, they risk suffering the indirect impacts of policy decisions, many of which appear to have been made with next to no explicit consideration of their interests. Public health interventions should not only be about infectious disease control, they should consider a broad set of outcomes. In addition, they ought to consider vulnerability, including that in early childhood - a time when young children's brains are developing rapidly and are most susceptible to adversity. We believe that mandating masking of pre-school children is not in line with public health principles, and needs to be urgently re-considered.

Population perspective comparing COVID-19 to all and common causes of death during the first wave of the pandemic in seven European countries.

OBJECTIVES: Mortality statistics on the COVID-19 pandemic have led to widespread concern and fear. To contextualise these data, we compared mortality related to COVID-19 during the first wave of the pandemic across seven countries in Europe with all and common causes of death, stratifying by age and sex. We also calculated deaths as a proportion of the population by age and sex. STUDY DESIGN: Analysis of population mortality data. METHODS: COVID-19 related mortality and population statistics from seven European countries were extracted: England and Wales, Italy, Germany, Spain, France, Portugal and Netherlands. Available data spanned 14-16 weeks since the first recorded deaths in each country, except Spain, where only comparable stratified data over an 8-week time period was available. The Global Burden of Disease database provided data on all deaths and those from pneumonia, cardiovascular disease combining ischaemic heart disease and stroke, chronic obstructive pulmonary disease, cancer, road traffic accidents and dementia in 2017. RESULTS: Deaths related to COVID-19, while modest overall, varied considerably by age. Deaths as a percentage of all cause deaths during the time period under study ranged from <0.01% in children in Germany, Portugal and Netherlands, to as high as 41.65% for men aged over 80 years in England and Wales. The percentage of the population who died from COVID-19 was less than 0.2% in every age group under the age of 80. In each country, over the age of 80, these proportions were: England and Wales 1.27% males, 0.87% females; Italy 0.6% males, 0.38% females; Germany 0.13% males, 0.09% females; France 0.39% males, 0.2% females; Portugal 0.2% males, 0.15% females; and Netherlands 0.6% males, 0.4% females. CONCLUSIONS: Mortality rates from COVID-19 during the first wave of the pandemic were low including when compared to other common causes of death and are likely to decline further while control measures are maintained, treatments improve and vaccination is instituted. These data may help people to contextualise their risk and for decision-making by policymakers.

The association of a novel digital tool for assessment of early childhood cognitive development, 'DEvelopmental assessment on an E-Platform (DEEP)', with growth in rural India: A proof of concept study.

BACKGROUND: There is an urgent need to fill the gap of scalable cognitive assessment tools for preschool children to enable identification of children at-risk of sub-optimal development and to support their timely referral into interventions. We present the associations between growth in early childhood, a well-established marker of cognitive development, and scores on a novel digital cognitive assessment tool called DEvelopmental Assessment on an E-Platform (DEEP) on a sample of 3-year old pre-schoolers from a rural region in north India. METHODS: Between February 2018 and March 2019, 1359 children from the Sustainable Programme Incorporating Nutrition and Games (SPRING) programme were followed up at 3-years age and data on DEEP, anthropometry and a clinical developmental assessment, the Bayley's Scale of Infant and Toddler Development, 3rd edition (BSID-III) was collected. DEEP data from 200 children was used to train a machine learning algorithm to predict their score on the cognitive domain of BSID-III. The DEEP score of the remaining 1159 children was then predicted using this algorithm to examine the cross-sectional and prospective association of growth with the DEEP score. FINDINGS: The magnitude of the concurrent positive association between height-for-age and cognitive z-scores in 3-year olds was similar when cognition was measured by BSID-III (0.20 standard deviations increase for every unit change in specifically age-adjusted height (HAZ), 95% CI = 0.06-0.35) and DEEP (0.26 CI, 0.11-0.41). A similar positive prospective relationship was found between growth at 18 (0.21 CI, 0.17-0.26) and 12-months (0.18 CI, 0.13-0.23) and DEEP score measured at 3-years. Additionally, the relationship between growth and cognitive development was found to be dependant on socioeconomic status (SES). INTERPRETATION: In this study, we suggest the utility of DEEP, a scalable, digital cognitive assessment tool, to measure cognition in preschool children. Further validation in different and larger datasets is necessary to confirm our findings. FUNDING: The SPRING Programme was funded through a Wellcome Trust programme grant and the follow-up study by the Corporate Social Responsibility initiative grant from Madura Microfinance Ltd.

Who actually cares for children in slums? Why we need to think, and do, more about paid childcare in urbanizing sub-Saharan Africa.

The early years are critical and inform the developmental trajectory of children. This is justifiably attracting growing policy attention. Much of this attention is focused on interventions and policies directed at parents, especially mothers. Yet emerging evidence suggests that increasing numbers of children in rapidly urbanizing low- and middle-income countries are now spending much of their day with other formal and informal childcare providers, including largely unregulated paid childcare providers. This paper summarizes the limited literature about the use of such paid childcare in low- and middle-income countries in sub-Saharan Africa, before considering possible reasons behind the lack of research evidence. Finally, key research gaps and their implications for public health practice are explored, with reference to the ongoing British Academy funded Nairobi Early Childcare in Slums research programme in Nairobi, Kenya. We argue that improving childcare may be an under-explored strategy to help some of the world's most disadvantaged children in the most important period of their lives, and that interventions in this largely informal market should be built on a rigorous research base. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.

Using the Mothers Object Relations Scale for early childhood development research in rural India: Findings from the Early Life Stress Sub-study of the SPRING Cluster Randomised Controlled Trial (SPRING-ELS).

Background: The World Health Organization and others promote responsive caregiving to support all children to thrive, particularly in low- and middle-income countries. The 14-item Mother's Object Relations Scales - Short Form (MORS-SF) may be of use in research and public health programmes because of its basis in attachment theory and ability to capture parental feelings towards their child. Methods: We culturally adapted the MORS-SF for use with mothers in the SPRING home visits trial when their infants were 12 months old. The same dyads were assessed using the HOME inventory concurrently and Bayley Scales of Infant Development III (BSID-III) at 18 months of age. Mixed effects linear regression was used to examine associations between MORS-SF (explanatory variable) and HOME-IT, and the cognitive, language and motor domains of BSID-III (outcome variables). Results: 1273 dyads completed all assessments. For the motor and language BSID-III scales and for HOME-IT there were strong and positive associations with the MORS-SF warmth sub-scale, and strong and negative associations with the invasion sub-scale. Important but less strong associations were seen with the BSID-III cognitive scale. Evidence of interaction suggested that both are individually important for child development. Conclusions: This is the first time MORS-SF has been used in India where optimising responsive caregiving is of importance in supporting all children to reach their potential. It is also the first time that the tool has been used in relation to child development. MORS-SF could be a valuable addition to evaluation in early childhood development.

Erratum to "COVID-19 in children: what did we learn from the first waveË® [Paediatr Child Health 30 (2020) 438-443/1496].

[This corrects the article DOI: 10.1016/j.paed.2020.09.005.].

Illness duration and symptom profile in symptomatic UK school-aged children tested for SARS-CoV-2.

BACKGROUND: In children, SARS-CoV-2 infection is usually asymptomatic or causes a mild illness of short duration. Persistent illness has been reported; however, its prevalence and characteristics are unclear. We aimed to determine illness duration and characteristics in symptomatic UK school-aged children tested for SARS-CoV-2 using data from the COVID Symptom Study, one of the largest UK citizen participatory epidemiological studies to date. METHODS: In this prospective cohort study, data from UK school-aged children (age 5-17 years) were reported by an adult proxy. Participants were voluntary, and used a mobile application (app) launched jointly by Zoe Limited and King's College London. Illness duration and symptom prevalence, duration, and burden were analysed for children testing positive for SARS-CoV-2 for whom illness duration could be determined, and were assessed overall and for younger (age 5-11 years) and older (age 12-17 years) groups. Children with longer than 1 week between symptomatic reports on the app were excluded from analysis. Data from symptomatic children testing negative for SARS-CoV-2, matched 1:1 for age, gender, and week of testing, were also assessed. FINDINGS: 258 790 children aged 5-17 years were reported by an adult proxy between March 24, 2020, and Feb 22, 2021, of whom 75 529 had valid test results for SARS-CoV-2. 1734 children (588 younger and 1146 older children) had a positive SARS-CoV-2 test result and calculable illness duration within the study timeframe (illness onset between Sept 1, 2020, and Jan 24, 2021). The most common symptoms were headache (1079 [62·2%] of 1734 children), and fatigue (954 [55·0%] of 1734 children). Median illness duration was 6 days (IQR 3-11) versus 3 days (2-7) in children testing negative, and was positively associated with age (Spearman's rank-order rs 0·19, p<0·0001). Median illness duration was longer for older children (7 days, IQR 3-12) than younger children (5 days, 2-9). 77 (4·4%) of 1734 children had illness duration of at least 28 days, more commonly in older than younger children (59 [5·1%] of 1146 older children vs 18 [3·1%] of 588 younger children; p=0·046). The commonest symptoms experienced by these children during the first 4 weeks of illness were fatigue (65 [84·4%] of 77), headache (60 [77·9%] of 77), and anosmia (60 [77·9%] of 77); however, after day 28 the symptom burden was low (median 2 symptoms, IQR 1-4) compared with the first week of illness (median 6 symptoms, 4-8). Only 25 (1·8%) of 1379 children experienced symptoms for at least 56 days. Few children (15 children, 0·9%) in the negatively tested cohort had symptoms for at least 28 days; however, these children experienced greater symptom burden throughout their illness (9 symptoms, IQR 7·7-11·0 vs 8, 6-9) and after day 28 (5 symptoms, IQR 1·5-6·5 vs 2, 1-4) than did children who tested positive for SARS-CoV-2. INTERPRETATION: Although COVID-19 in children is usually of short duration with low symptom burden, some children with COVID-19 experience prolonged illness duration. Reassuringly, symptom burden in these children did not increase with time, and most recovered by day 56. Some children who tested negative for SARS-CoV-2 also had persistent and burdensome illness. A holistic approach for all children with persistent illness during the pandemic is appropriate. FUNDING: Zoe Limited, UK Government Department of Health and Social Care, Wellcome Trust, UK Engineering and Physical Sciences Research Council, UK Research and Innovation London Medical Imaging and Artificial Intelligence Centre for Value Based Healthcare, UK National Institute for Health Research, UK Medical Research Council, British Heart Foundation, and Alzheimer's Society.