SARS-CoV-2 tests, confirmed infections and COVID-19-related hospital admissions in children and young people: birth cohort study.

BACKGROUND: There have been no population-based studies of SARS-CoV-2 testing, PCR-confirmed infections and COVID-19-related hospital admissions across the full paediatric age range. We examine the epidemiology of SARS-CoV-2 in children and young people (CYP) aged <23 years. METHODS: We used a birth cohort of all children born in Scotland since 1997, constructed via linkage between vital statistics, hospital records and SARS-CoV-2 surveillance data. We calculated risks of tests and PCR-confirmed infections per 1000 CYP-years between August and December 2020, and COVID-19-related hospital admissions per 100 000 CYP-years between February and December 2020. We used Poisson and Cox proportional hazards regression models to determine risk factors. RESULTS: Among the 1 226 855 CYP in the cohort, there were 378 402 tests (a rate of 770.8/1000 CYP-years (95% CI 768.4 to 773.3)), 19 005 PCR-confirmed infections (179.4/1000 CYP-years (176.9 to 182.0)) and 346 admissions (29.4/100 000 CYP-years (26.3 to 32.8)). Infants had the highest COVID-19-related admission rates. The presence of chronic conditions, particularly multiple types of conditions, was strongly associated with COVID-19-related admissions across all ages. Overall, 49% of admitted CYP had at least one chronic condition recorded. CONCLUSIONS: Infants and CYP with chronic conditions are at highest risk of admission with COVID-19. Half of admitted CYP had chronic conditions. Studies examining COVID-19 vaccine effectiveness among children with chronic conditions and whether maternal vaccine during pregnancy prevents COVID-19 admissions in infants are urgently needed.

SARS-CoV-2 testing, infections, and hospital admissions with COVID-19 in children and young people in Scotland: a birth cohort study

Background A strong association between deprivation and severe COVID-19 outcomes has been reported among adults. We estimated population-based rates of SARS-CoV-2 testing, laboratory-confirmed infections, and hospital admissions with COVID-19 in children and young people (aged 0–23 years) in Scotland according to sociodemographic risk factors. Methods We used a birth cohort of all children and young people born in Scotland in 1997–2020, consisting of linked vital registration, maternity, hospital admissions, and SARS-CoV-2 PCR testing data. Participants were followed from birth or Jan 1, 2020 (whichever occurred last) until Dec 31, 2020, death, or emigration. Admissions with COVID-19 were defined as participants with a positive SARS-CoV-2 test during or up to 28 days before admission to hospital, or a relevant International Classification of Diseases version 10 code recorded (U07.1/U07.2). We calculated crude rates of tests, laboratory-confirmed infections, and admissions, by age group, sex, and Scottish Index of Multiple Deprivation (SIMD) quintiles with 95% CIs. Findings The cohort included 1 230 290 children and young people living in Scotland during 2020. By Dec 31, 2020, 243 958 (19·8%) were tested for SARS-CoV-2 at least once, and 17 709 (7·3%) had tested positive. Infants (aged <2 years) and 18–23-year-olds were most likely to be tested;there was no clear trend in testing rates by SIMD quintile. 18–23-year-olds, females, and those from the most deprived SIMD quintile were most likely to test positive. 379 participants had an admission with COVID-19, corresponding to a rate of 32·0 per 100 000 person-years (95% CI 28·9–35·4). Females (admission rate 35·4 per 100 000 person-years [95% CI 30·9–40·6]) and infants (143·5 per 100 000 person-years [113·3–181·7]) were most likely to be admitted to hospital. There was a clear gradient in hospital admissions by SIMD, with participants in the most deprived quintile (42·9 per 100 000 person-years [36·1–50·8]) experiencing 1·9 times (95% CI 1·3–2·6) the admission rate compared with those in the least deprived (22·6 per 100 000 person-years [16·9–30·3]). Interpretation Rates of infection and admissions with COVID-19 were associated with area-level deprivation among children and young people. Infants had a relatively low infection rate but the highest admission rate. Analyses examining risk factors, including ethnic group and long-term conditions are underway, to inform the public health response to SARS-CoV-2 in children. Although children and young people in Scotland had low COVID-19-related admission rates versus adults, a socioeconomic gradient was evident, indicating children living in more deprived areas are at increased risk of short-term, and potential long-term, health and education impacts of COVID-19. Funding UKRI Medical Research Council and the Great Ormond Street Biomedical Research Centre.

Air Pollution, housing and respirfatory tract Infections in Children: NatIonal birth Cohort study (PICNIC): study protocol.

INTRODUCTION: Respiratory tract infections (RTIs) are the most common reason for hospital admission among children <5 years in the UK. The relative contribution of ambient air pollution exposure and adverse housing conditions to RTI admissions in young children is unclear and has not been assessed in a UK context. METHODS AND ANALYSIS: The aim of the PICNIC study (Air Pollution, housing and respiratory tract Infections in Children: NatIonal birth Cohort Study) is to quantify the extent to which in-utero, infant and childhood exposures to ambient air pollution and adverse housing conditions are associated with risk of RTI admissions in children <5 years old. We will use national administrative data birth cohorts, including data from all children born in England in 2005-2014 and in Scotland in 1997-2020, created via linkage between civil registration, maternity and hospital admission data sets. We will further enhance these cohorts via linkage to census data on housing conditions and socioeconomic position and small area-level data on ambient air pollution and building characteristics. We will use time-to-event analyses to examine the association between air pollution, housing characteristics and the risk of RTI admissions in children, calculate population attributable fractions for ambient air pollution and housing characteristics, and use causal mediation analyses to explore the mechanisms through which housing and air pollution influence the risk of infant RTI admission. ETHICS, EXPECTED IMPACT AND DISSEMINATION: To date, we have obtained approval from six ethics and information governance committees in England and two in Scotland. Our results will inform parents, national and local governments, the National Health Service and voluntary sector organisations of the relative contribution of adverse housing conditions and air pollution to RTI admissions in young children. We will publish our results in open-access journals and present our results to the public via parent groups and social media and on the PICNIC website. Code and metadata will be published on GitHub.