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Abstract Background Our study examines if SARS-CoV-2 infections varied by vaccination status, if an individual had previously tested positive and by neighbourhood socioeconomic deprivation across the Delta and Omicron epidemic waves of SARS-CoV-2. Methods Population cohort study using electronic health records for 2.7 M residents in Cheshire and Merseyside, England (3rd June 2021 to 1st March 2022). Our outcome variable was registered positive test for SARS-CoV-2. Explanatory variables were vaccination status, previous registered positive test and neighbourhood socioeconomic deprivation. Cox regression models were used to analyse associations. Results Originally higher SARS-CoV-2 rates in the most socioeconomically deprived neighbourhoods changed to being higher in the least deprived neighbourhoods from the 1st September 2021, and were inconsistent during the Omicron wave. Individuals who were fully vaccinated (two doses) were associated with fewer registered positive tests (e.g., individuals engaged in testing between 1st September and 27th November 2021—Hazards Ratio (HR) = 0.48, 95% Confidence Intervals (CIs) = 0.47–0.50. Individuals with a previous registered positive test were also less likely to have a registered positive test (e.g., individuals engaged in testing between 1st September and 27th November 2021—HR = 0.16, 95% CIs = 0.15–0.18. However, the Omicron period saw smaller effect sizes for both vaccination status and previous registered positive test. Conclusions Changing patterns of SARS-CoV-2 infections during the Delta and Omicron waves reveals a dynamic pandemic that continues to affect diverse communities in sometimes unexpected ways.

Summary: Background: Covid-19 test-to-release from quarantine policies affect many lives. The SMART Release pilot was the foundation of these policies and an element of the world's largest population cohort study of community-wide, SARS-CoV-2 rapid antigen testing. The objective of the study was to evaluate daily lateral flow testing (LFT) as an alternative to 10-14 days quarantine for key worker contacts of known Covid-19 (or SARS-CoV-2 infection) cases. Methods: Prospective cohort study incorporating quantitative and qualitative research methods to consider how serial LFT compares with PCR testing to detect SARS-CoV-2 infections and to understand experiences/compliance with testing and the viability of this quarantine harm-reduction strategy. Participants were residents of the Liverpool area who were key workers at participating fire, police, NHS and local government organisations in Liverpool, and who were identified as close contacts of cases between December 2020 and August 2021. Thematic qualitative analysis was used to evaluate stakeholder meetings. Findings: Compliance with the daily testing regime was good across the three main organisations in this study with 96·9%, 93·7% and 92·8% compliance for Merseyside Police, Merseyside Fire & Rescue Service and Alder Hey Children's Hospital respectively. Out of 1657 participants, 34 positive Covid-19 cases were identified and 3 undetected by the daily LFT regime. A total of 8291 workdays would have been lost to self-isolation but were prevented due to negative daily tests. Organisations reported that daily contact testing proved useful, flexible and well-tolerated initiative to sustain key worker services. Interpretation: Compliance with daily testing among key workers was high, helping sustain service continuity during periods of very high risk of staffing shortage. Services reported that the pilot was a “lifeline” and its successful delivery in Liverpool has been replicated elsewhere. Funding: This report is independent research commissioned by DHSC and part funded by DHSC and NIHR. Further funding was received from Liverpool City Council, the EPSRC and MRC.

Background: Large-scale asymptomatic testing of communities in Liverpool (UK) for SARS-CoV-2 was used as a public health tool for containing COVID-19. The aim of the study is to explore social and spatial inequalities in uptake and case-detection of rapid lateral flow SARS-CoV-2 antigen tests (LFTs) offered to people without symptoms of COVID-19. Methods: Linked pseudonymised records for asymptomatic residents in Liverpool who received a LFT for COVID-19 between 6th November 2020 to 31st January 2021 were accessed using the Combined Intelligence for Population Health Action resource. Bayesian Hierarchical Poisson Besag, York, and Mollié models were used to estimate ecological associations for uptake and positivity of testing. Findings: 214 525 residents (43%) received a LFT identifying 5192 individuals as positive cases of COVID-19 (1.3% of tests were positive). Uptake was highest in November when there was military assistance. High uptake was observed again in the week preceding Christmas and was sustained into a national lockdown. Overall uptake were lower among males (e.g. 40% uptake over the whole period), Black Asian and other Minority Ethnic groups (e.g. 27% uptake for ‘Mixed’ ethnicity) and in the most deprived areas (e.g. 32% uptake in most deprived areas). These population groups were also more likely to have received positive tests for COVID-19. Models demonstrated that uptake and repeat testing were lower in areas of higher deprivation, areas located further from test sites and areas containing populations less confident in the using Internet technologies. Positive tests were spatially clustered in deprived areas. Interpretation: Large-scale voluntary asymptomatic community testing saw social, ethnic, digital and spatial inequalities in uptake. COVID-19 testing and support to isolate need to be more accessible to the vulnerable communities most impacted by the pandemic, including non-digital means of access. Funding: Department of Health and Social Care (UK) and Economic and Social Research Council.

To describe the incidence and progression of retinopathy in people with diabetes in Southern Malawi over 5 years. To document visual loss in a setting where laser treatment is not available.Subjects from a cohort sampled from a hospital-based, primary-care diabetes clinic in 2007 were traced in 2012. Laser treatment was not available. Modified Wisconsin grading of retinopathy was performed using slit lamp biomicroscopy by a single ophthalmologist in 2007 and using four-field mydriatic fundus photographs at an accredited reading centre in 2012. Visual acuity was measured by Snellen chart in 2007 and by 'Early Treatment of Diabetic Retinopathy Study' chart in 2012. HbA1c, blood pressure, HIV status, urine albumin-creatinine ratio, haemoglobin and lipids were measured.Of 281 subjects recruited in 2007, 135 (48%) were traced and assessed, 15 were confirmed dead. At follow-up (median 5.3 years) ≥2 step retinopathy progression was observed in 48 subjects (36.4%; 95% CI 28.2-44.6). Incidence of sight threatening diabetic retinopathy for those with level 10 (no retinopathy) and level 20 (background) retinopathy at baseline, was 19.4% (11.3-27.4) and 81.3% (62.1-100), respectively. In multivariate analysis 2 step progression was associated with HbA1c (OR 1.2495%CI 1.04-1.48), and haemoglobin level (0.77, 0.62-0.98). 25 subjects (18.8%) lost ≥5 letters, 7 (5.3%) lost ≥15 letters.Progression to sight threatening diabetic retinopathy from no retinopathy and background retinopathy was approximately 5 and 3 times that reported in recent European studies, respectively. Incidence of visual loss was high in a location where treatment was not available.

Cavalieri sampling and point counting are frequently applied in combination with magnetic resonance (MR) imaging to estimate the volume of human brain compartments. Current practice involves arbitrarily choosing the number of sections and sampling intensity within each section, and subsequently applying error prediction formulae to estimate the precision. The aim of this study is to derive a reference table for researchers who are interested in estimating the volume of brain regions, namely grey matter, white matter, and their union, to a given precision. In particular, this table, which is based on subsampling of a large brain data set obtained from coronal MR images, offers a recommendation for the minimum number of sections and mean number of points per section that are required to achieve a pre-defined coefficient of error of the volume estimator. Further analysis onMR brain data from a second human brain shows that the sampling intensity recommended is appropriate.

Cerebral malaria (CM) remains a significant global health challenge with high morbidity and mortality. Malarial retinopathy has been shown to be diagnostically and prognostically significant in the assessment of CM. The major mechanism of death in paediatric CM is brain swelling. Long term morbidity is typically characterised by neurological and neurodevelopmental sequelae. Optical coherence tomography can be used to quantify papilloedema and macular ischaemia, identified as hyperreflectivity. Here we describe a protocol to test the hypotheses that quantification of optic nerve head swelling using optical coherence tomography can identify severe brain swelling in CM, and that quantification of hyperreflectivity in the macula predicts neurodevelopmental outcomes post-recovery. Additionally, our protocol includes the development of a novel, low-cost, handheld optical coherence tomography machine and artificial intelligence tools to assist in image analysis.

ObjectivesEncephalitis, brain inflammation and swelling, most often caused by an infection or the body's immune defences, can have devastating consequences, especially if diagnosed late. We looked for clinical predictors of different types of encephalitis to help clinicians consider earlier treatment.MethodsWe conducted a multicentre prospective observational cohort study (ENCEPH-UK) of adults (> 16 years) with suspected encephalitis at 31 UK hospitals. We evaluated clinical features and investigated for infectious and autoimmune causes.Results341 patients were enrolled between December 2012 and December 2015 and followed up for 12 months. 233 had encephalitis, of whom 65 (28%) had HSV, 38 (16%) had confirmed or probable autoimmune encephalitis, and 87 (37%) had no cause found. The median time from admission to 1st dose of aciclovir for those with HSV was 14 hours (IQR 5-50); time to 1st dose of immunosuppressant for the autoimmune group was 125 hours (IQR 45-250). Compared to non-HSV encephalitis, patients with HSV more often had fever, lower serum sodium and lacked a rash. Those with probable or confirmed autoimmune encephalitis were more likely to be female, have abnormal movements, normal serum sodium levels and a cerebrospinal fluid white cell count < 20 cells x106/L, but they were less likely to have a febrile illness.ConclusionsInitiation of treatment for autoimmune encephalitis is delayed considerably compared with HSV encephalitis. Clinical features can help identify patients with autoimmune disease and could be used to initiate earlier presumptive therapy.

Background: Combination antiretroviral therapy (cART) is the standard for human immunodeficiency virus (HIV) infection treatment but can result in metabolic abnormalities, such as insulin resistance, dyslipidaemia and lipodystrophy, which can increase the risk of cardiovascular disease. Objective: The objective of the trial was to evaluate whether or not telmisartan, an angiotensin II receptor antagonist and a peroxisome proliferator-activated receptor-γ partial agonist, could reduce insulin resistance in HIV-positive individuals on cART, and affect blood and imaging biomarkers of cardiometabolic disease. Design: A Phase II, multicentre, randomised, open-labelled, dose-ranging trial of telmisartan over a period of 48 weeks with an adaptive design comprising two stages was used to identify the optimal dose of telmisartan. Participants were randomised to receive one of the three doses of telmisartan (20, 40 and 80 mg) or no intervention (control). Setting: Recruitment was from 19 HIV specialist centres in the UK. Participants: A total of 377 patients infected with HIV who met the prespecified inclusion/exclusion criteria. Interventions: 20-, 40- and 80-mg tablets of telmisartan. Main outcome measures: The primary outcome measure was reduction in the homeostatic model assessment of insulin resistance (HOMA-IR), a marker of insulin resistance, at 24 weeks. Secondary outcome measures were changes in plasma lipid profile; Quantitative Insulin Sensitivity Check Index (QUICKI) and revised QUICKI, alternative markers of insulin resistance, plasma adipokines (adiponectin, leptin, interleukin 8, tumour necrosis factor alpha, resistin); high-sensitivity C-reactive protein (hs-CRP); body fat redistribution, as measured by magnetic resonance imaging/proton magnetic resonance spectroscopy; changes in renal markers (albumin-to-creatinine ratio, neutrophil gelatinase-associated lipocalin); and tolerability to telmisartan. Results: At the interim analysis, 80 mg of telmisartan was taken forward into the second stage of the study. Baseline characteristics were balanced across treatment arms. There were no differences in HOMA-IR [0.007, standard error (SE) 0.106], QUICKI (0.001, SE 0.001) and revised QUICKI (0.002, SE 0.002) at 24 weeks between the telmisartan (80 mg; n = 106) and non-intervention (n = 105) arms. Longitudinal analysis over 48 weeks showed that there was no change in HOMA-IR, lipid or adipokine levels; however, but there were significant, but marginal, improvements in revised QUICKI [0.004, 95% confidence interval (CI) 0.000 to 0.008] and plasma hs-CRP (–0.222, 95% CI –0.433 to –0.011) over 48 weeks. Substudies also showed a significant reduction in the liver fat content at 24 weeks (1.714, 95% CI –2.787 to –0.642; p = 0.005) and urinary albumin excretion at 48 weeks (–0.665, 95% CI –1.31 to –0.019; p = 0.04). There were no differences in serious adverse events between the telmisartan and control arms. Limitations: The patients had modest elevations of HOMA-IR at baseline, and our trial could have been under-powered to detect smaller improvements in insulin resistance over time. Conclusions: Using a novel adaptive design, we demonstrated that there was no significant effect of telmisartan (80 mg) on the primary outcome measure of HOMA-IR and some secondary outcomes (plasma lipids and adipokines). Telmisartan did lead to favourable, and biologically plausible, changes of the secondary longitudinal outcome measures: revised QUICKI, hs-CRP, hepatic fat accumulation and urinary albumin excretion. Taken collectively, our findings showed that telmisartan did not reduce insulin resistance in patients infected with HIV on antiretrovirals. Future work: The mechanistic basis of adipocyte regulation will be studied to allow for development of biomarkers and interventions. Trial registration: Current Controlled Trials ISRCTN51069819. Funding: This project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council and National Institute for Health Research partnership.

Abstract Background Covid-19 healthcare worker testing, isolation and quarantine policies had to balance risks to patients from the virus and from staff absence. The emergence of the Omicron variant led to dangerous levels of key-worker absence globally. We evaluated whether using two manufacturers’ lateral flow tests (LFTs) concurrently improved SARS-CoV-2 Omicron detection significantly and was acceptable to hospital staff. In a nested study, to understand risks of return to work after a 5-day isolation/quarantine period, we examined virus culture 5–7 days after positive test or significant exposure. Methods Fully-vaccinated Liverpool (UK) University Hospitals staff participated (February-May 2022) in a random-order, open-label trial testing whether dual LFTs improved SARS-CoV-2 detection, and whether dual swabbing was acceptable to users. Participants used nose-throat swab Innova and nose-only swab Orient Gene LFTs in daily randomised order for 10 days. A user-experience questionnaire was administered on exit. Selected participants gave swabs for viral culture on days 5–7 after symptom onset or first positive test. Cultures were considered positive if cytopathic effect was apparent or SARS-CoV-2 N gene sub-genomic RNA was detected. Results Two hundred and twenty-six individuals reported 1466 pairs of LFT results. Tests disagreed in 127 cases (8.7%). Orient Gene was more likely (78 cf. 49; OR: 2.1, 1.1–4.1; P = 0.03) to be positive. If Innova was swabbed second, it was less likely to agree with a positive Orient Gene result (OR: 2.7, 1.3–5.2; P = 0.005); swabbing first with Innova made no significant difference (OR: 1.1, 0.5–2.3; P = 0.85). Orient Gene positive Innova negative result-pairs became more frequent over time (OR: 1.2, 1.1–1.3; P

The diagnosis of inflammatory bowel disease (IBD) in children and the need to distinguish between subtypes (Crohn’s disease (CD) and ulcerative colitis (UC)) requires lengthy investigative and invasive procedures. Non-invasive, rapid, and cost-effective tests to support these diagnoses are needed. Faecal volatile organic compounds (VOCs) are distinctive in IBD. VOC profiles can be rapidly determined using a gas chromatography–sensor device (OdoReader©). In an inception-cohort of children presenting with suspected IBD, we directly compared the diagnostic fidelity of faecal calprotectin (FCP, a non-specific protein marker of intestinal inflammation) with OdoReader© VOC profiles of children subsequently diagnosed with IBD with matched controls diagnosed with other gastrointestinal conditions. The OdoReader© was 82% (95% confidence interval 75–89%) sensitive and 71% (61–80%) specific but did not outperform FCP (sensitivity 93% (77–99%) and specificity 86% (67–96%); 250 µg/g FCP cut off) in the diagnosis of IBD from other gastrointestinal conditions when validated in a separate sample from the same cohort. However, unlike FCP and better than other similar technologies, the OdoReader© could distinguish paediatric CD from UC (up to 88% (82–93%) sensitivity and 80% (71–89%) specificity in the validation set) and justifies further validation in larger studies. A non-invasive test based on VOCs could help streamline and limit invasive investigations in children.

Background Systematic annual screening for sight-threatening diabetic retinopathy is established in several countries but is resource intensive. Personalised (individualised) medicine offers the opportunity to extend screening intervals for people at low risk of progression and to target high-risk groups. However, significant concern exists among all stakeholders around the safety of changing programmes. Evidence to guide decisions is limited, with, to the best of our knowledge, no randomised controlled trials to date. Objectives To develop an individualised approach to screening for sight-threatening diabetic retinopathy and test its acceptability, safety, efficacy and cost-effectiveness. To estimate the changing incidence of patient-centred outcomes. Design A risk calculation engine; a randomised controlled trial, including a within-trial cost-effectiveness study; a qualitative acceptability study; and an observational epidemiological cohort study were developed. A patient and public group was involved in design and interpretation. Setting A screening programme in an English health district of around 450,000 people. Participants People with diabetes aged ≥ 12 years registered with primary care practices in Liverpool. Interventions The risk calculation engine estimated each participant’s risk at each visit of progression to screen-positive diabetic retinopathy (individualised intervention group) and allocated their next appointment at 6, 12 or 24 months (high, medium or low risk, respectively). Main outcome measures The randomised controlled trial primary outcome was attendance at first follow-up assessing the safety of individualised compared with usual screening. Secondary outcomes were overall attendance, rates of screen-positive and sight-threatening diabetic retinopathy, and measures of visual impairment. Cost-effectiveness outcomes were cost/quality-adjusted life year and incremental cost savings. Cohort study outcomes were rates of screen-positive diabetic retinopathy and sight-threatening diabetic retinopathy. Data sources Local screening programme (retinopathy), primary care (demographic, clinical) and hospital outcomes. Methods A seven-person patient and public involvement group was recruited. Data were linked into a purpose-built dynamic data warehouse. In the risk assessment, the risk calculation engine used patient-embedded covariate data, a continuous Markov model, 5-year historical local population data, and most recent individual demographic, retina and clinical data to predict risk of future progression to screen-positive. The randomised controlled trial was a masked, two-arm, parallel assignment, equivalence randomised controlled trial, with an independent trials unit and 1 : 1 allocation to individualised screening (6, 12 or 24 months, determined by risk calculation engine at each visit) or annual screening (control). Cost-effectiveness was assessed using a within-trial analysis over a 2-year time horizon, including NHS and societal perspectives and costs directly observed within the randomised controlled trial. Acceptability was assessed by purposive sampling of 60 people with diabetes and 21 healthcare professionals with semistructured interviews analysed thematically; this was a constant comparative method until saturation. The cohort was an 11-year retrospective/prospective screening population data set. Results In the randomised controlled trial, 4534 participants were randomised: 2097 out of 2265 in the individualised arm (92.6%) and 2224 out of 2269 in the control arm (98.0%) remained after withdrawals. Attendance rates at first follow-up were equivalent (individualised 83.6%, control 84.7%) (difference –1.0%, 95% confidence interval –3.2% to 1.2%). Sight-threatening diabetic retinopathy detection rates were non-inferior: individualised 1.4%, control 1.7% (difference –0.3%, 95% confidence interval –1.1% to 0.5%). In the cost-effectiveness analysis, the mean differences in complete-case quality-adjusted life years (EuroQol-5 Dimensions, five-level version, and Health Utilities Index Mark 3) did not significantly differ from zero. Incremental cost savings per person not including treatment costs were from the NHS perspective £17.34 (confidence interval £17.02 to £17.67) and the societal perspective £23.11 (confidence interval £22.73 to £23.53). In the individualised arm, 43.2% fewer screening appointments were required. In terms of acceptability, changing to variable intervals was acceptable for the majority of people with diabetes and health-care professionals. Annual screening was perceived as unsustainable and an inefficient use of resources. Many people with diabetes and healthcare professionals expressed concerns that 2-year screening intervals may detect referable eye disease too late and might have a negative effect on perceptions about the importance of attendance and diabetes care. The 6-month interval was perceived positively. Among people with dementia, there was considerable misunderstanding about eye-related appointments and care. In the cohort study, the numbers of participants (total 28,384) rose over the 11 years (2006/7, n = 6637; 2016/17, n = 14,864). Annual incidences ranged as follows: screen-positive 4.4–10.6%, due to diabetic retinopathy 2.3–4.6% and sight-threatening diabetic retinopathy 1.3–2.2%. The proportions of screen-positive fell steadily but sight-threatening diabetic retinopathy rates remained stable. Limitations Our findings apply to a single city-wide established English screening programme of mostly white people with diabetes. The cost-effectiveness analysis was over a short timeline for a long-standing disease; the study, however, was designed to test the safety and effectiveness of the screening regimen, not the cost-effectiveness of screening compared with no screening. Cohort data collection was partly retrospective: data were unavailable on people who had developed sight-threatening diabetic retinopathy or died prior to 2013. Conclusions Our randomised controlled trial can reassure stakeholders involved in diabetes care that extended intervals and personalised screening is feasible, where data linkage is possible, and can be safely introduced in established screening programmes with potential cost savings compared with annual screening. Rates of screen-positive diabetic retinopathy and sight-threatening diabetic retinopathy are low and show consistent falls over time. Involvement of patients in research is crucial to success. Future work Future work could include external validation with other programmes followed by scale-up of individualised screening outside a research setting and economic modelling beyond the 2-year time horizon. Trial registration This trial is registered as ISRCTN87561257. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Programme Grants for Applied Research programme and will be published in full in Programme Grants for Applied Research; Vol. 11, No. 6. See the NIHR Journals Library website for further project information. Plain language summary Diabetic retinopathy remains a leading cause of vision loss for people with diabetes. Annual photographic screening allows early detection and prompt treatment in many countries. A new approach is to vary how often this is undertaken at each visit, after calculating each person’s risk of progression; we have called this ‘individualised’ screening. We tested this variable-interval risk-based approach against annual screening in a randomised controlled trial of 4534 people in Liverpool. Six-, 12- or 24-month intervals represented high, medium and low risks, respectively, of becoming screen-positive by the next appointment. With our patient and public involvement group, we designed a computer-based risk-calculation system using personal information from screening, general practitioners and hospitals. Attendance rates at the next screening appointment were similar in the individualised (84%) and annual (control) (85%) groups. Similar amounts of sight-threatening diabetic retinopathy were detected in the two arms (1.4% individualised, 1.7% control), with 43% fewer visits. In this study in a single geographical region, savings estimated to accrue to the NHS per person over 2 years were £17.34 and £23.11 for wider society, but estimates did not include treatment costs. During interviews, 60 people with diabetes and 21 healthcare professionals said that individualised screening would be acceptable because of increasing rates of diabetes and the chance to target high-risk people. Patients had anxieties about the reliability of the risk-calculation and restricting access, requesting opportunities for earlier screening if risks changed. Varying screening intervals based on a person’s own risk of progression appears feasible and safe. Low-risk people would be spared unnecessary appointments. Introducing an individualised approach could now move to wider testing and validation in other UK and international settings. The trial only ran for 2 years and was in a long-established programme with low rates of disease, so monitoring of attendance and retinopathy rates should be included as part of wider testing. Scientific summary Background Diabetic retinopathy remains the most common cause of visual impairment in working populations worldwide. Systematic annual screening to detect and treat sight-threatening diabetic retinopathy (STDR) is established in several countries including the United Kingdom (UK) and has greatly improved the detection of treatable disease. With the rapid increase in the prevalence of diabetes, new approaches to screening are required. Risk stratification, personalised (individualised) medicine, and clinical bioinformatics offer opportunities to extend the screening interval for people at low risk of progression and to target those at high risk. However there is significant concern among people with diabetes, healthcare professionals and health commissioners in the UK around the safety and acceptability of changing an established and successful programme. To ensure that health care is available for all it is imperative that it is not only efficacious but cost-efficient, that is, it delivers care at an affordable cost for commissioners. Evidence to guide these decisions is very limited and there are no randomised controlled trials (RCTs). Much of the data on prevalence and incidence of diabetic retinopathy and progression to more severe stages of disease come from the 1980s to 1990s and before the introduction of systematic screening and improvements in diabetes and blood pressure control. Data on the current progression rates in screening populations are limited and are reported variably. We conducted a programme of quantitative and qualitative research to develop and test the acceptability, safety, efficacy and cost-effectiveness of an individualised approach to screening for STDR. To provide data for future planning of early detection programmes and the design of future research studies we designed a longitudinal observational cohort study of the population of people with diabetes in Liverpool. We aimed to investigate the prevalence and incidence of the stages in the natural history of diabetic retinopathy, namely screen-positive, sight-threatening and treatable disease, and visual impairment, all key patient-centred outcomes in the disease. Changes to the programme and their implications A number of changes to the programme occurred in the early years. A systematic review was published at around the time of the programme start. We used these data to design aspects of the study and conducted a literature review instead. Data for the cohort study proved not to be available on people who had died prior to programme start. We adopted a mixed retrospective and prospective analysis but this added some difficulty in interpreting the findings. In 2016 resources were repurposed from the cohort study to support recruitment of the RCT, which was behind schedule. The scope of the cohort study was narrowed to focus only on the data available from the screening programme, meaning that we were unable to complete data collection on the patient-centred outcomes after sight-threatening retinopathy had been confirmed, namely treatment and visual impairment. Recruitment of non-attenders proved beyond the resources available and was abandoned. Further research is needed to address these unanswered questions. Methods The programme included the development of a bespoke data warehouse, the development of a risk-calculation engine, a RCT, a within-trial cost-effectiveness study, a qualitative study of acceptability, and an observational cohort study. We recruited and fully embedded a seven-person patient and public involvement group which was maintained throughout the programme. The setting was the screening programme of a single English health district (clinical commissioning group). All people with diabetes aged 12 years and over registered with general practices in the Liverpool city area were invited by letter to participate in the research programme. Consent was through an opt-out process. A purpose-built dynamic data warehouse was developed to support all aspects of the programme including bespoke processes addressing inconsistency in routinely collected data, multiple data platforms and lack of technical manuals. Data on eligible participants were sourced from primary care (demographic, clinical), Liverpool Diabetes Eye Screening Programme (retinopathy) and hospital outcomes (true screen-positive, STDR). Data were cross referenced against opt-out records before further use within the programme. A risk-calculation engine was developed for the assessment of individual risk of progressing to screen-positive using patient-focused covariate selection, a continuous-time Markov model, 5-year historical local population data, and the most recent individual demographic, retina and clinical data. The risk-calculation engine was linked to the data warehouse. The Patient and Public Involvement group determined the risk criterion of

Objective To evaluate the impact of mobile vaccination units on COVID-19 vaccine uptake of the first dose, the percentage of vaccinated people among the total eligible population. We further investigate whether such an effect differed by deprivation, ethnicity and age.Design Synthetic control analysis.Setting The population registered with general practices (GPs) in nine local authority areas in Cheshire and Merseyside in Northwest England, UK.Intervention Mobile vaccination units that visited 37 sites on 54 occasions between 12 April 2021 and 28 June 2021. We defined intervention neighbourhoods as having their population weighted centroid located within 1 km of mobile vaccination sites (338 006 individuals). A weighted combination of neighbourhoods that had not received the intervention (1 495 582 individuals) was used to construct a synthetic control group.Outcome The weekly number of first-dose vaccines received among people aged 18 years and over as a proportion of the population.Results The introduction of a mobile vaccination unit into a neighbourhood increased the number of first vaccinations conducted in the neighbourhood by 25% (95% CI 21% to 28%) within 3 weeks after the first visit to a neighbourhood, compared with the synthetic control group. Interaction analyses showed smaller or no effect among older age groups, Asian and black ethnic groups, and the most socioeconomically deprived populations.Conclusions Mobile vaccination units are effective interventions for increasing vaccination uptake, at least in the short term. While mobile units can be geographically targeted to reduce inequalities, we found evidence that they may increase inequalities in vaccine uptake within targeted areas, as the intervention was less effective among groups that tended to have lower vaccination uptake. Mobile vaccination units should be used in combination with activities to maximise outreach with black and Asian communities and socioeconomically disadvantaged groups.

Abstract Background From January to May 2021 the alpha variant (B.1.1.7) of SARS-CoV-2 was the most commonly detected variant in the UK. Following this, the Delta variant (B.1.617.2) then became the predominant variant. The UK COVID-19 vaccination programme started on 8th December 2020. Prior to the Delta variant, most vaccine effectiveness studies focused on the alpha variant. We therefore aimed to estimate the effectiveness of the BNT162b2 (Pfizer-BioNTech) and the ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccines in preventing symptomatic and asymptomatic infection with respect to the Delta variant in a UK setting. Methods We used anonymised public health record data linked to infection data (PCR) using the Combined Intelligence for Population Health Action resource. We then constructed an SIR epidemic model to explain SARS-CoV-2 infection data across the Cheshire and Merseyside region of the UK. Vaccines were assumed to be effective after 21 days for 1 dose and 14 days for 2 doses. Results We determined that the effectiveness of the Oxford-AstraZeneca vaccine in reducing susceptibility to infection is 39% (95% credible interval [34, 43]) and 64% (95% credible interval [61, 67]) for a single dose and a double dose respectively. For the Pfizer-BioNTech vaccine, the effectiveness is 20% (95% credible interval [10, 28]) and 84% (95% credible interval [82, 86]) for a single-dose and a double dose respectively. Conclusion Vaccine effectiveness for reducing susceptibility to SARS-CoV-2 infection shows noticeable improvement after receiving two doses of either vaccine. Findings also suggest that a full course of the Pfizer-BioNTech provides the optimal protection against infection with the Delta variant. This reinforces the need to complete the full course programme to maximise individual protection and reduce transmission.

Abstract Background In clinical research, there is an increasing interest in joint modelling of longitudinal and time-to-event data, since it reduces bias in parameter estimation and increases the efficiency of statistical inference. Inference and prediction from frequentist approaches of joint models have been extensively reviewed, and due to the recent popularity of data-driven Bayesian approaches, a review on current Bayesian estimation of joint model is useful to draw recommendations for future researches. Methods We have undertaken a comprehensive review on Bayesian univariate and multivariate joint models. We focused on type of outcomes, model assumptions, association structure, estimation algorithm, dynamic prediction and software implementation. Results A total of 89 articles have been identified, consisting of 75 methodological and 14 applied articles. The most common approach to model the longitudinal and time-to-event outcomes jointly included linear mixed effect models with proportional hazards. A random effect association structure was generally used for linking the two sub-models. Markov Chain Monte Carlo (MCMC) algorithms were commonly used (93% articles) to estimate the model parameters. Only six articles were primarily focused on dynamic predictions for longitudinal or event-time outcomes. Conclusion Methodologies for a wide variety of data types have been proposed; however the research is limited if the association between the two outcomes changes over time, and there is also lack of methods to determine the association structure in the absence of clinical background knowledge. Joint modelling has been proved to be beneficial in producing more accurate dynamic prediction; however, there is a lack of sufficient tools to validate the prediction.

Cavalieri sampling is often used to estimate the volume of an object with systematic sections a constant distance T apart. The variance of the corresponding estimator can be expressed as the sum of the extension term (which gives the overall trend of the variance and is used to estimate it), the 'Zitterbewegung' (which oscillates about zero) and higher order terms. The extension term is of order T2m+2 for small T, where m is the order of the first non-continuous derivative of the measurement function f, (namely of the area function if the target is the volume). A key condition is that the jumps of the mth derivative f (m) of f are finite. When this is not the case, then the variance exhibits a fractional trend, and the current theory fails. Indeed, in practice the mentioned trend is often of order T2q+2, typically with 0