Background:Childhood residential mobility (RM) has been associated with adverse health and social outcomes. We examined differences in RM by family size and household composition in two diverse, disadvantaged UK populations. Methods:Using electronic health records (EHRs) and anonymised addresses, we examined if household characteristics are associated with RM in north-east London (NEL) and Wales. We conducted a longitudinal study of 240,509 (51.0 per cent male) and 398,959 (51.3 per cent male) children aged 0-13 years in NEL and Wales respectively on 1 January 2015, with complete follow-up until 31 December 2019. We defined RM as at least one change in address during follow-up. We estimated odds ratios (OR) and 95 per cent confidence intervals (CI) for RM by interactions between age group (0-4, 5-9, 10-13 years), number of children in household and household composition, adjusting for demographic, household and area-level characteristics. Results:Overall, 20.6 per cent and 32.1 per cent of children experienced RM. RM was highest in the youngest age group: NEL: 25.3 per cent, 18.7 per cent, 15.6 per cent; Wales: 40.1 per cent, 29.4 per cent, 23.6 per cent. RM was more likely among 10-13-year-olds living with a single adult than two working-age adults (NEL OR: 1.15; 95 per cent CI: 1.07,1.25; Wales: 1.82; 1.73,1.91). Children in households with four or more children were more likely to experience RM than those with no other child among 10-13-year-olds in NEL (1.31; 1.18,1.46) and 5-9-year-olds and 10-13-year-olds in Wales (1.21; 1.14,1.29 and 1.68; 1.56,1.82). Conclusion:RM is more common in early childhood and varies by household composition, region and age group. EHRs can be used to estimate RM using real-world data and have the potential to examine its impact on health and other outcomes.

Background Residential mobility in early life may disrupt access to health care. We examined associations between residential mobility in the first two years of life and receipt of first measles, mumps and rubella (MMR) vaccination by 24 months of age. Methods We analysed electronic health records for children born between 01/01/2014 and 30/10/2019 and registered with primary care general practices (GPs) in north-east London (NEL). Primary outcome was receipt of first MMR vaccination between 12 and 24 months of age and residential mobility was defined by number of GP-recorded addresses by vaccination date or 24 months of age. We used logistic regression to estimate the odds ratio (OR) and 95% confidence intervals (CI) of receipt of MMR vaccination by residential mobility, adjusting for sex, ethnicity, number of children in the household, household composition, area-level deprivation, and local government area of residence. Results We included 150,949 children (51.0% boys) of whom 127,958 (84.8%) had received a first MMR vaccination and 22.3% had more than one GP-recorded address. Compared to children with one GP-recorded address, children with multiple GP-recorded addresses were at higher risk of not receiving their first MMR vaccination by 24 months of age. Those with two GP-recorded addresses had a 54% increased likelihood (OR: 0.46; 95% CI: 0.44,0.48), and those with three or more GP-recorded addresses a 68% increased likelihood (0.32; 95% CI: 0.29,0.36), compared to those with one. Conclusions Children who change address in early life are less likely to be protected against measles and other infections. Measles outbreaks in the UK have been in urban areas with high residential mobility and low MMR vaccine uptake suggesting the need for review of the immunisation status of children newly registered with GPs.

Background An unknown proportion of mothers are involved in both the Criminal Justice and Family Justice Systems. Mothers with cross-justice involvement are at risk of losing their children from their care on a temporary or permanent basis. Objectives Speaking directly to the Female Offender Strategy for England and Wales and the imperative to preserve mother-child relationships wherever safe and in the child's best interests, the Child Outcomes for Mothers Facing Trial (COMFT) study aims to uncover mothers' dual system involvement and provide vital insights about caregiver outcomes for children. The project will use administrative data to deliver the first-ever quantitative analyses of mothers and children at the intersection of the criminal and family justice systems. Methods The project will link female defendant records in England and Wales to mother and child family court records (public and private law), as well as demographic data. Data will be accessed through the globally leading Secure Anonymised Information Linkage (SAIL) Databank at Swansea University. The proposal has been developed collaboratively with project partners, committed to transforming justice outcomes for women and children, including the Ministry of Justice (MoJ), the Children and Family Court Advisory and Support Service (Cafcass), Cafcass Cymru and the leading charity, Birth Companions. Formal ethical approval has been granted by the Universities involved. Patient and Public Involvement A unique feature of this project is that from design to completion, a group of mothers with lived experience are directly involved. The 'COMFT-Together' advisory group ensures that the perspectives of women with cross-justice involvement inform this study, and that mothers benefit directly from a shared research role and curriculum facilitated by Birth Companions. Implications As the study is the first of its kind, it will also serve as an international exemplar, relevant to policy makers across the globe wishing to use routine organisational data to inform public services delivery.

Objectives Understanding the sociodemographic drivers of childhood residential mobility is important due to associations with adverse health and educational outcomes. Using electronic health records (EHRs) and residential anonymised linkage fields (RALFs), we examined if household characteristics are associated with residential mobility in two distinct geographies: Wales and north-east London (NEL). Method We carried out an observational longitudinal study using EHRs from the SAIL Databank (Wales) and Discovery Data Service (NEL). We included 398,959 (51.3% male) children in Wales and 240,509 (51.0% male) children in NEL, aged 0-13 years on 1/1/2015, with complete follow-up until 31/12/2019. We defined residential mobility as at least one change in RALF during the five-year follow-up period. We estimated odds ratios (OR) and 95% confidence intervals (CI) for residential mobility by interactions between age group (0-4, 5-9, 10-13 years), number of children in the household, and household composition, adjusting for baseline demographic-, household-, and area-level characteristics. Results 32.1% and 21.6% of children experienced residential mobility, with 9.1% and 3.0% moving more than once in Wales and NEL respectively. In both geographies, residential mobility decreased as age group increased: NEL: 25.3%, 18.7%, 15.6%; Wales: 40.1%, 29.4%, 23.6%. In the fully adjusted model including interactions, all children in Wales, and 10-13-year-olds in NEL living with a single adult were more likely to experience residential mobility (10-13-year-olds in Wales: OR: 1.82; 95%CI: 1.73,1.91; NEL: 1.15; 1.07,1.25) compared with those living with two working-age adults. 5-13-year-olds in Wales and 10-13-year-olds in NEL were more likely to experience residential mobility if there were four or more children in the household (Wales 5-9-year-olds: OR: 1.21; 95%CI: 1.14,1.29; 10-13-years-olds: 1.68; 1.56,1.82; NEL 10-13-year-olds: 1.31; 1.18,1.46) compared with one child. Conclusion We examined residential mobility in two distinct geographies with different levels of ethnic diversity and area-level deprivation. Given the wide-ranging adverse impacts of high residential mobility, our cross-country comparison provides a more comprehensive understanding of the characteristics of those who move, with the potential to better support families.

Introduction Linkage of population-based administrative data is a powerful tool for studying important public issues. To overcome confidentiality and disclosure issues, records are de-identified and allocated a unique identifier. Within the Secure Anonymised Information Linkage (SAIL) Databank, these are known as Anonymised Linking Fields (ALFs). Assignment of an ALF enables linkage of individuals across multiple routinely collected datasets. Within the Children Looked After (CLA) Wales dataset, only 37% of the children have an ALF, limiting linkage to other datasets and, as a result, potential research. There are also other known data issues, including discrepancies with the week of births, duplicate identifiers and year-on-year changes in identifiers. Objectives To improve accuracy and availability of the ALFs in the CLA dataset, and overall research quality. Methods Using several datasets within the SAIL Databank, we developed a six-step CLA matching algorithm to improve the ALF matching rate and correct for data errors. To assess the performance of our algorithm, we benchmarked against routine ALFs already identified via the algorithm currently used by SAIL. Results Our algorithm increased ALF matching by 25%, assigning 61% of individuals an ALF. Inconsistent weeks of birth, and incorrect and duplicate identifiers were resolved. When benchmarking against the current ALF-assigning algorithm used by SAIL, our algorithm had an overall sensitivity of 90%. Conclusion We have developed an algorithm which demonstrates comparable ALF matching performance to the current algorithm used within SAIL, and which greatly improves the ALF matching in the CLA dataset. This algorithm may help to overcome potential bias due to missing data, and increases the potential for linkage to other datasets. Further development and refinement could result in the algorithm being applied to other datasets in SAIL.

ObjectiveCoverage for the measles, mumps and rubella (MMR) vaccination in north-east London (NEL) is the lowest in the United Kingdom. It has been hypothesised that children who move home frequently are less likely to receive vaccinations. We examined the association between number of addresses in the first two years of life, and receipt of MMR vaccination by age two. ApproachWe derived households by pseudonymously linking the addresses of 178,028 children registered with a NEL general practitioner (GP) on their second birthday (2015-2021). We included 135,221 (76.0%) children (51.0% male) after excluding 42,807 with invalid household characteristics at age 24 months. The outcome was MMR vaccination by 24 months. Residential mobility was categorised by number of addresses (1, 2, ≥3) between earliest GP-registration and vaccination date/second birthday. We calculated the percentage receiving MMR by residential mobility and estimated adjusted odds (aOR; 95% confidence intervals [CI]) for MMR receipt. Results105,392 (77.9%) children received MMR by age two, and 26,652 (19.7%) had more than one address. Receipt of MMR decreased with increasing residential mobility: 80.9% (95% CI: 80.6,81.1), 66.5% (65.9,67.1), and 58.6% (56.2,60.9) for children with one, two, or three or more addresses respectively. Children with multiple addresses were less likely to receive MMR by age two: aOR: 0.53 (0.51,0.55); 0.36 (0.32,0.40) for 2 and ≥3 addresses respectively. Conclusions Uptake of MMR vaccine by two years of age is lower in children with multiple addresses. Further research is needed to identify actionable opportunities to improve MMR uptake in mobile populations.

The COVID-19 pandemic has profoundly impacted the lives of people living with dementia (PLWD). Mitigating measures have led to extreme social isolation and reduced or limited capacity within routine health and social care services. Using anonymised individual-level, population-scale linked electronic healthcare, demographic and mortality records in Wales, we have examined the impact of the COVID-19 pandemic on all-cause mortality in PLWD and in older adults living with other comorbid conditions. Using the Secure Anonymised Information Linkage (SAIL) Databank (Lyons et al., 2009), we identified six cohorts of individuals aged 50-101 and living in Wales on or before 1 st February 2020, with conditions in the following domains: dementia, cardiovascular, respiratory, metabolic, renal, and cerebrovascular. For each, we identified paired samples matched by age and sex using propensity sampling. Evidence for comorbidities were extracted using ICD-10 and READ codes. We quantified excess mortality in PLWD during the COVID-19 period (July 2020 – May 2021 at the point of the analysis) by comparing weekly mortality to a baseline rate (2015-2019 average) and to the population paired sample. We then extracted retrospective datasets across sixteen-month periods from 2010-2020. Finally, we estimated all-cause mortality odds-ratios for each period and comorbid domain using logistic regression, controlling for age and sex. PLWD had higher risk of all-cause mortality compared to a matched sample of individuals without dementia (Figure 1a), especially during the first wave of the pandemic (April 2020, Figure 1b), and in older PLWD (Figure 1c). Examining evidence across other comorbid conditions (Figure 2), logistic regression modelling showed the greatest increase in mortality odds among PLWD (Figure 2f) compared to people without dementia, increasing from 4.47 in 2018 to 5.61 in 2020. The magnitude of the increase in odds among people with cardiovascular, metabolic, renal, and cerebrovascular conditions from 2020-2021 compared to previous years was smaller compared to the increase in PLWD (Figures 2a, 2c-e). PLWD experienced increased mortality risk compared to those living with other comorbid conditions during 2020. Further work will focus on the composition of death causes and the contribution of other comorbidities to all-cause mortality among PLWD.

Research-ready data (data curated to a defined standard) increase scientific opportunity and rigour by integrating the data environment. The development of research platforms has highlighted the value of research-ready data, particularly for multi-cohort analyses. Following stakeholder consultation, a standard data model (C-Surv) optimised for data discovery, was developed using data from 5 population and clinical cohort studies. The model uses a four-tier nested structure based on 18 data themes selected according to user behaviour or technology. Standard variable naming conventions are applied to uniquely identify variables within the context of longitudinal studies. The data model was used to develop a harmon-ised dataset for 11 cohorts. This dataset populated the Cohort Explorer data discovery tool for assessing the feasibility of an analysis prior to making a data access request. Data preparation times were compared between cohort specific data models and C-Surv.It was concluded that adopting a common data model as a data standard for the discovery and analysis of research cohort data offers multiple benefits.

Objectives We aim to determine the proportion of infants entering care in Wales via the two primary legal routes (section 76 of the Social Services and Wellbeing (Wales) Act 2014, and section 31 of the Children Act 1989), and associations between mode of entry and infant characteristics and outcomes. Approach This is a longitudinal cohort study using routinely collected data held in the Secure Anonymised Information Linkage (SAIL) Databank. We will link the Looked After Children dataset with family justice (Cafcass Cymru) data on section 31 proceedings, to explore pathways through the care and family justice systems for infants aged <1 year entering care in Wales between 2012 and 2019. We will follow up each child for two years from the date of their entry into care to track legal outcomes (final legal orders) and placement outcomes (placement type, number of placements, and re-entry into the care system). Results Descriptive statistics will include frequencies and proportions of infants who initially enter the care system via voluntary arrangements (section 76) and care proceedings (section 31), by age, year, local authority, and category of need. We will describe the proportion and characteristics of those with voluntary arrangements who later become the subject of care proceedings, and the distribution of final legal orders and placement types by initial route of entry to care. We will use funnel plots to investigate variation between local authorities. We will use linear regression to test for statistically significant differences in the proportions of infants entering care via the two different routes over time, and chi-square tests to investigate associations between mode of entry and infant characteristics and outcomes. Conclusion There is limited information on the care journeys of children in Wales at the individual level. This study will help us to understand the patterns of use of voluntary arrangements for infants over time, the proportion subsequently involved in section 31 applications and the impact on outcomes for children.

Introduction COVID-19 risk prediction algorithms can be used to identify at-risk individuals from short-term serious adverse COVID-19 outcomes such as hospitalisation and death. It is important to validate these algorithms in different and diverse populations to help guide risk management decisions and target vaccination and treatment programs to the most vulnerable individuals in society. Objectives To validate externally the QCOVID risk prediction algorithm that predicts mortality outcomes from COVID-19 in the adult population of Wales, UK. Methods We conducted a retrospective cohort study using routinely collected individual-level data held in the Secure Anonymised Information Linkage (SAIL) Databank. The cohort included individuals aged between 19 and 100 years, living in Wales on 24th January 2020, registered with a SAIL-providing general practice, and followed-up to death or study end (28th July 2020). Demographic, primary and secondary healthcare, and dispensing data were used to derive all the predictor variables used to develop the published QCOVID algorithm. Mortality data were used to define time to confirmed or suspected COVID-19 death. Performance metrics, including R2 values (explained variation), Brier scores, and measures of discrimination and calibration were calculated for two periods (24th January–30th April 2020 and 1st May–28th July 2020) to assess algorithm performance. Results 1,956,760 individuals were included. 1,192 (0.06%) and 610 (0.03%) COVID-19 deaths occurred in the first and second time periods, respectively. The algorithms fitted the Welsh data and population well, explaining 68.8% (95% CI: 66.9-70.4) of the variation in time to death, Harrell’s C statistic: 0.929 (95% CI: 0.921-0.937) and D statistic: 3.036 (95% CI: 2.913-3.159) for males in the first period. Similar results were found for females and in the second time period for both sexes. Conclusions The QCOVID algorithm developed in England can be used for public health risk management for the adult Welsh population.

Objectives To better understand the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers, leading to recommendations for the prioritisation of personal protective equipment, testing, training and vaccination. Design Observational, longitudinal, national cohort study. Setting Our cohort were secondary care (hospital-based) healthcare workers employed by NHS Wales (United Kingdom) organisations from 1 April 2020 to 30 November 2020. Participants We included 577,756 monthly observations among 77,587 healthcare workers. Using linked anonymised datasets, participants were grouped into 20 staff roles. Additionally, each role was deemed either patient-facing, non-patient-facing or undetermined. This was linked to individual demographic details and dates of positive SARS-CoV-2 PCR tests. Main outcome measures We used univariable and multivariable logistic regression models to determine odds ratios (ORs) for the risk of a positive SARS-CoV-2 PCR test. Results Patient-facing healthcare workers were at the highest risk of SARS-CoV-2 infection with an adjusted OR (95% confidence interval [CI]) of 2.28 (95% CI 2.10–2.47). We found that after adjustment, foundation year doctors (OR 1.83 [95% CI 1.47–2.27]), healthcare support workers [OR 1.36 [95% CI 1.20–1.54]) and hospital nurses (OR 1.27 [95% CI 1.12–1.44]) were at the highest risk of infection among all staff groups. Younger healthcare workers and those living in more deprived areas were at a higher risk of infection. We also observed that infection rates varied over time and by organisation. Conclusions These findings have important policy implications for the prioritisation of vaccination, testing, training and personal protective equipment provision for patient-facing roles and the higher risk staff groups.

Abstract Background falls are common in older people, but associations between falls, dementia and frailty are relatively unknown. The impact of the COVID-19 pandemic on falls admissions has not been studied. Aim to investigate the impact of dementia, frailty, deprivation, previous falls and the differences between years for falls resulting in an emergency department (ED) or hospital admission. Study Design longitudinal cross-sectional observational study. Setting older people (aged 65+) resident in Wales between 1 January 2010 and 31 December 2020. Methods we created a binary (yes/no) indicator for a fall resulting in an attendance to an ED, hospital or both, per person, per year. We analysed the outcomes using multilevel logistic and multinomial models. Results we analysed a total of 5,141,244 person years of data from 781,081 individuals. Fall admission rates were highest in 2012 (4.27%) and lowest in 2020 (4.27%). We found an increased odds ratio (OR [95% confidence interval]) of a fall admission for age (1.05 [1.05, 1.05] per year of age), people with dementia (2.03 [2.00, 2.06]) and people who had a previous fall (2.55 [2.51, 2.60]). Compared with fit individuals, those with frailty had ORs of 1.60 [1.58, 1.62], 2.24 [2.21, 2.28] and 2.94 [2.89, 3.00] for mild, moderate and severe frailty respectively. Reduced odds were observed for males (0.73 [0.73, 0.74]) and less deprived areas; most deprived compared with least OR 0.75 [0.74, 0.76]. Conclusions falls prevention should be targeted to those at highest risk, and investigations into the reduction in admissions in 2020 is warranted.

Background: While population estimates suggest high vaccine effectiveness against SARS-CoV-2 infection, the protection for health care workers, who are at higher risk of SARS-CoV-2 exposure, is less understood. Methods: We conducted a national cohort study of health care workers in Wales (UK) from 7 December 2020 to 30 September 2021. We examined uptake of any COVID-19 vaccine, and the effectiveness of BNT162b2 mRNA (Pfizer-BioNTech) against polymerase chain reaction (PCR) confirmed SARS-CoV-2 infection. We used linked and routinely collected national-scale data within the SAIL Databank. Data were available on 82,959 health care workers in Wales, with exposure extending to 26 weeks after second doses. Results: Overall vaccine uptake was high (90%), with most health care workers receiving the BNT162b2 vaccine (79%). Vaccine uptake differed by age, staff role, socioeconomic status; those aged 50-59 and 60+ years old were 1.6 times more likely to get vaccinated than those aged 16-29. Medical and dental staff, and Allied Health Practitioners were 1.5 and 1.1 times more likely to get vaccinated, compared to nursing and midwifery staff. The effectiveness of the BNT162b2 vaccine was found to be strong and consistent across the characteristics considered; 52% three to six weeks after first dose, 86% from two weeks after second dose, though this declined to 53% from 22 weeks after the second dose. Conclusions: With some variation in rate of uptake, those who were vaccinated had a reduced risk of PCRconfirmed SARS-CoV-2 infection, compared to those unvaccinated. Second dose has provided stronger protection for longer than first dose but our study is consistent with waning from seven weeks onwards. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Abstract Background dementia may increase care home residents’ risk of COVID-19, but there is a lack of evidence on this effect and on interactions with individual and care home-level factors. Methods we created a national cross-sectional retrospective cohort of care home residents in Wales for 1 September to 31 December 2020. Risk factors were analysed using multi-level logistic regression to model the likelihood of SARS-CoV-2 infection and mortality. Results the cohort included 9,571 individuals in 673 homes. Dementia was diagnosed in 5,647 individuals (59%); 1,488 (15.5%) individuals tested positive for SARS-CoV-2. We estimated the effects of age, dementia, frailty, care home size, proportion of residents with dementia, nursing and dementia services, communal space and region. The final model included the proportion of residents with dementia (OR for positive test 4.54 (95% CIs 1.55–13.27) where 75% of residents had dementia compared to no residents with dementia) and frailty (OR 1.29 (95% CIs 1.05–1.59) for severe frailty compared with no frailty). Analysis suggested 76% of the variation was due to setting rather than individual factors. Additional analysis suggested severe frailty and proportion of residents with dementia was associated with all-cause mortality, as was dementia diagnosis. Mortality analyses were challenging to interpret. Discussion whilst individual frailty increased the risk of COVID-19 infection, dementia was a risk factor at care home but not individual level. These findings suggest whole-setting interventions, particularly in homes with high proportions of residents with dementia and including those with low/no individual risk factors may reduce the impact of COVID-19.

Background A defining feature of the COVID-19 pandemic in many countries was the tragic extent to which care home residents were affected, and the difficulty preventing introduction and subsequent spread of infection. Management of risk in care homes requires good evidence on the most important transmission pathways. One hypothesised route at the start of the pandemic, prior to widespread testing, was transfer of patients from hospitals, which were experiencing high levels of nosocomial events. Methods We tested the hypothesis that hospital discharge events increased the intensity of care home cases using a national individually linked health record cohort in Wales, UK. We monitored 186,772 hospital discharge events over the period March to July 2020, tracking individuals to 923 care homes and recording the daily case rate in the homes populated by 15,772 residents. We estimated the risk of an increase in cases rates following exposure to a hospital discharge using multi-level hierarchical logistic regression, and a novel stochastic Hawkes process outbreak model. Findings In regression analysis, after adjusting for care home size, we found no significant association between hospital discharge and subsequent increases in care home case numbers (odds ratio: 0.99, 95% CI 0.82, 1.90). Risk factors for increased cases included care home size, care home resident density, and provision of nursing care. Using our outbreak model, we found a significant effect of hospital discharge on the subsequent intensity of cases. However, the effect was small, and considerably less than the effect of care home size, suggesting the highest risk of introduction came from interaction with the community. We estimated approximately 1.8% of hospital discharged patients may have been infected. Interpretation There is growing evidence in the UK that the risk of transfer of COVID-19 from the high-risk hospital setting to the high-risk care home setting during the early stages of the pandemic was relatively small. Although access to testing was limited to initial symptomatic cases in each care home at this time, our results suggest that reduced numbers of discharges, selection of patients, and action taken within care homes following transfer all may have contributed to mitigation. The precise key transmission routes from the community remain to be quantified.

IntroductionUnder section 31 of the Children Act 1989, public law care proceedings can be issued if there is concern a child is subject to, or at risk of significant harm, which can lead to removal of a child from parents. Appropriate and effective health and social support are required to potentially prevent some of the need for these proceedings. More comprehensive evidence of the health needs and vulnerabilities of parents will enable enhanced response from family courts and integrated other services. ObjectiveTo examine health vulnerabilities of parents involved in care proceedings in the two-year period prior to involvement. MethodsFamily court data provided by Cafcass Cymru were linked to population-based health records held within the Secure Anonymised Information Linkage Databank. Linked data were available for 8,821 parents of children involved in care proceedings between 2011 and 2019. Findings were benchmarked with reference to a comparison group of parents matched on sex, age, and deprivation (n = 32,006), not subject to care proceedings. Demographic characteristics, overall health service use, and health profiles of parents were examined. Descriptive and statistical tests of independence were used. ResultsNearly half of cohort parents (47.6%) resided in the most deprived quintile. They had higher levels of healthcare use compared to the comparison group across multiple healthcare settings, with the most pronounced differences for emergency department attendances (59.3% vs 37.0%). Health conditions with the largest variation between groups were related to mental health (43.6% vs 16.0%), substance use (19.4% vs 1.6%) and injuries (41.5% vs 23.6%). ConclusionThis study highlights the heightened socioeconomic and health vulnerabilities of parents who experience care proceedings concerning a child. Better understanding of the needs and vulnerabilities of this population may provide opportunities to improve a range of support and preventative interventions that respond to crises in the community.

Background COVID-19 vaccinations have been prioritised for high risk individuals. Aim Determine individual-level risk factors for care home residents testing positive for SARS-CoV-2. Study design Longitudinal observational cohort study using individual-level linked data from the Secure Anonymised Information Linkage (SAIL) databank. Setting Fourteen thousand seven hundred and eighty-six older care home residents (aged 65+) living in Wales between 1 September 2020 and 1 May 2021. Our dataset consisted of 2,613,341 individual-level daily observations within 697 care homes. Methods We estimated odds ratios (ORs [95% confidence interval]) using multilevel logistic regression models. Our outcome of interest was a positive SARS-CoV-2 PCR test. We included time-dependent covariates for the estimated community positive test rate of COVID-19, hospital inpatient status, vaccination status and frailty. Additional covariates were included for age, sex and specialist care home services. Results The multivariable regression model indicated an increase in age (OR 1.01 [1.00,1.01] per year), community positive test rate (OR 1.13 [1.12,1.13] per percent increase), hospital inpatients (OR 7.40 [6.54,8.36]), and residents in care homes with non-specialist dementia care (OR 1.42 [1.01,1.99]) had an increased odds of a positive test. Having a positive test prior to the observation period (OR 0.58 [0.49,0.68]) and either one or two doses of a vaccine (0.21 [0.17,0.25] and 0.05 [0.02,0.09], respectively) were associated with a decreased odds. Conclusions Care providers need to remain vigilant despite the vaccination rollout, and extra precautions should be taken when caring for the most vulnerable. Minimising potential COVID-19 infection for care home residents when admitted to hospital should be prioritised.

BackgroundPopulation-level information on dispensed medication provides insight on the distribution of treated morbidities, particularly if linked to other population-scale data at an individual-level. ObjectiveTo evaluate the impact of COVID-19 on dispensing patterns of medications. MethodsRetrospective observational study using population-scale, individual-level dispensing records in Wales, UK. Total dispensed drug items for the population between 1st January 2016 and 31st December 2019 (3-years, pre-COVID-19) were compared to 2020 with follow up until 27th July 2021 (COVID-19 period). We compared trends across all years and British National Formulary (BNF) chapters and highlighted the trends in three major chapters for 2019-21: 1-Cardiovascular system (CVD); 2-Central Nervous System (CNS); 3-Immunological & Vaccine. We developed an interactive dashboard to enable monitoring of changes as the pandemic evolves. ResultAmongst all BNF chapters, 73,410,543 items were dispensed in 2020 compared to 74,121,180 items in 2019 demonstrating -0.96% relative decrease in 2020. Comparison of monthly patterns showed average difference (D) of -59,220 and average Relative Change (RC) of -0.74% between the number of dispensed items in 2020 and 2019. Maximum RC was observed in March 2020 (D= +1,224,909 and RC= +20.62%), followed by second peak in June 2020 (D= +257,920, RC= +4.50%). A third peak was observed in September 2020 (D= +264,138, RC= +4.35%). Large increases in March 2020 were observed for CVD and CNS medications across all age groups. The Immunological and Vaccine products dropped to very low levels across all age groups and all months (including the March dispensing peak). ConclusionsReconfiguration of routine clinical services during COVID-19 led to substantial changes in community pharmacy drug dispensing. This change may contribute to a long-term burden of COVID-19, raising the importance of a comprehensive and timely monitoring of changes for evaluation of the potential impact on clinical care and outcomes.

Introduction The novel coronavirus SARS-CoV-2, which emerged in December 2019, has caused millions of deaths and severe illness worldwide. Numerous vaccines are currently under development of which a few have now been authorised for population-level administration by several countries. As of 20 September 2021, over 48 million people have received their first vaccine dose and over 44 million people have received their second vaccine dose across the UK. We aim to assess the uptake rates, effectiveness, and safety of all currently approved COVID-19 vaccines in the UK. Methods and analysis We will use prospective cohort study designs to assess vaccine uptake, effectiveness and safety against clinical outcomes and deaths. Test-negative case–control study design will be used to assess vaccine effectiveness (VE) against laboratory confirmed SARS-CoV-2 infection. Self-controlled case series and retrospective cohort study designs will be carried out to assess vaccine safety against mild-to-moderate and severe adverse events, respectively. Individual-level pseudonymised data from primary care, secondary care, laboratory test and death records will be linked and analysed in secure research environments in each UK nation. Univariate and multivariate logistic regression models will be carried out to estimate vaccine uptake levels in relation to various population characteristics. VE estimates against laboratory confirmed SARS-CoV-2 infection will be generated using a generalised additive logistic model. Time-dependent Cox models will be used to estimate the VE against clinical outcomes and deaths. The safety of the vaccines will be assessed using logistic regression models with an offset for the length of the risk period. Where possible, data will be meta-analysed across the UK nations. Ethics and dissemination We obtained approvals from the National Research Ethics Service Committee, Southeast Scotland 02 (12/SS/0201), the Secure Anonymised Information Linkage independent Information Governance Review Panel project number 0911. Concerning English data, University of Oxford is compliant with the General Data Protection Regulation and the National Health Service (NHS) Digital Data Security and Protection Policy. This is an approved study (Integrated Research Application ID 301740, Health Research Authority (HRA) Research Ethics Committee 21/HRA/2786). The Oxford-Royal College of General Practitioners Clinical Informatics Digital Hub meets NHS Digital’s Data Security and Protection Toolkit requirements. In Northern Ireland, the project was approved by the Honest Broker Governance Board, project number 0064. Findings will be made available to national policy-makers, presented at conferences and published in peer-reviewed journals.

Objectives A defining feature of the COVID-19 pandemic in many countries were the tragic extent to which care home residents were affected and the difficulty in preventing the introduction and subsequent spread of infection. Approach Utilising linked data in the SAIL Databank we set out to develop a linked data platform as part of the ‘One Wales’ approach to generate evidence to inform policy makers on the key areas of transmission pathways, care home characteristics, excess mortality, and the impacts of vaccination. We used multi-sectoral linked data including routinely collected health data, administrative data and GIS generated metrics on care home characteristics and community infection rates to better understand how multiple factors impacted on care home residents. Results We created a care home index with enhanced care home characteristics for all care homes in Wales and were able to link 15,773 care home residents in the SAIL Databank to 923 care homes. We were able to generate early evidence demonstrating an increased risk of mortality for care home residents during Wave 1 (adjusted HR 1.72 compared to 2016). We were able to show that hospital discharge in Wales during the initial stages of the pandemic, although significant, had a much smaller impact on subsequent infections than care home size and accounted for 1.8% of infected discharge events. We also showed that community prevalence, inpatient appointments and people living with dementia all contributed to increased risks of catching COVID in a care home. Conclusion The response of the ‘One Wales’ team and the SAIL linked data platform facilitated meaningful insight on the impacts of COVID in social care settings in Wales. The evidence generated was used by policy makers from Welsh and UK Governments to inform policy direction as the pandemic progressed.