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1.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-336247

ABSTRACT

Objective To analyse the impact on hospital admissions for COVID-19 of large-scale, voluntary, public open access rapid testing for SARS-CoV-2 antigen in Liverpool (UK) between 6 th November 2020 and 2 nd January 2021. Design Synthetic control analysis comparing hospital admissions for small areas in the intervention population to a group of control areas weighted to be similar in terms of prior COVID-19 hospital admission rates and socio-demographic factors. Intervention COVID-SMART (Systematic Meaningful Asymptomatic Repeated Testing), a national pilot of large-scale, voluntary rapid antigen testing for people without symptoms of COVID-19 living or working in the City of Liverpool, deployed with the assistance of the British Army from the 6 th November 2020 in an unvaccinated population. This pilot informed the UK roll-out of SARS-CoV-2 antigen rapid testing, and similar policies internationally. Main outcome measure Weekly COVID-19 hospital admissions for neighbourhoods in England. Results The intensive introduction of COVID-SMART community testing was associated with a 43% (95% confidence interval: 29% to 57%) reduction in COVID-19 hospital admissions in Liverpool compared to control areas for the initial period of intensive testing with military assistance in national lockdown from 6 th November to 3 rd December 2020. A 25% (11% to 35%) reduction was estimated across the overall intervention period (6 th November 2020 to 2 nd January 2021), involving fewer testing centres, before England’s national roll-out of community testing, after adjusting for regional differences in Tiers of COVID-19 restrictions from 3 rd December 2020 to 2 nd January 2021. Conclusions The world’s first voluntary, city-wide SARS-CoV-2 rapid antigen testing pilot in Liverpool substantially reduced COVID-19 hospital admissions. Large scale asymptomatic rapid testing for SARS-CoV-2 can help reduce transmission and prevent hospital admissions. Summary box What is already known on this topic – Previous studies on managing the spread of SARS-CoV-2 have identified asymptomatic transmission as significant challenges for controlling the pandemic. – Along with non-pharmaceutical measures, many countries rolled out population-based asymptomatic testing programmes to further limit transmission. – Evidence is required on whether large scale voluntary testing of communities for COVID-19 reduces severe disease, by breaking chains of transmission. What this study adds – The findings of this study suggest that large scale rapid antigen testing of communities for SARS-CoV-2, within an agile local public health campaign, can reduce transmission and prevent hospital admissions. – The results indicate that policy makers should integrate such testing into comprehensive, local public health programmes targeting high risk groups, supporting those required to isolate and adapting promptly to prevailing biological, behavioural and environmental circumstances.

2.
BMJ Open ; 12(4): e054101, 2022 Apr 12.
Article in English | MEDLINE | ID: covidwho-1788960

ABSTRACT

OBJECTIVES: To analyse the impact on SARS-CoV-2 transmission of tier 3 restrictions introduced in October and December 2020 in England, compared with tier 2 restrictions. We further investigate whether these effects varied between small areas by deprivation. DESIGN: Synthetic control analysis. SETTING: We identified areas introducing tier 3 restrictions in October and December, constructed a synthetic control group of places under tier 2 restrictions and compared changes in weekly infections over a 4-week period. Using interaction analysis, we estimated whether this effect varied by deprivation and the prevalence of a new variant (B.1.1.7). INTERVENTIONS: In both October and December, no indoor between-household mixing was permitted in either tier 2 or 3. In October, no between-household mixing was permitted in private gardens and pubs and restaurants remained open only if they served a 'substantial meal' in tier 3, while in tier 2 meeting with up to six people in private gardens were allowed and all pubs and restaurants remained open. In December, in tier 3, pubs and restaurants were closed, while in tier 2, only those serving food remained open. The differences in restrictions between tier 2 and 3 on meeting outside remained the same as in October. MAIN OUTCOME MEASURE: Weekly reported cases adjusted for changing case detection rates for neighbourhoods in England. RESULTS: Introducing tier 3 restrictions in October and December was associated with a 14% (95% CI 10% to 19%) and 20% (95% CI 13% to 29%) reduction in infections, respectively, compared with the rates expected with tier 2 restrictions only. The effects were similar across levels of deprivation and by the prevalence of the new variant. CONCLUSIONS: Compared with tier 2 restrictions, additional restrictions in tier 3 areas in England had a moderate effect on transmission, which did not appear to increase socioeconomic inequalities in COVID-19 cases.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , COVID-19/prevention & control , Family Characteristics , Humans , Restaurants
3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332878

ABSTRACT

Objective To examine if SARS-CoV-2 infections vary 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. Design Cohort study using electronic health records Setting Cheshire and Merseyside, England (3 rd June 2021 to 1 st March 2022) Participants 2.7M residents Main Outcome measure Registered positive test for SARS-CoV-2 Results Social inequalities in registered positive tests were dynamic during the study. Originally higher SARS-CoV-2 rates in the most socioeconomically deprived neighbourhoods changed to being higher in the least deprived neighbourhoods from the 1 st September 2021. While the introduction of Omicron initially reset inequalities, they continued to be dynamic and inconsistent. Individuals who were fully vaccinated (two doses) were associated with fewer registered positive tests (e.g., between 1 st September and 27 th November 2021: (i) individuals engaged in testing – Hazards Ratio (HR) = 0.48, 95% Confidence Intervals (CIs) = 0.47-0.50;(ii) individuals engaged with healthcare - HR = 0.34, 95% CIs = 0.33-0.34). Individuals with a previous registered positive test were also less likely to have a registered positive test (e.g., between 1 st September and 27 th November 2021: (i) individuals engaged in testing - HR = 0.16, 95% CIs = 0.15-0.18;(ii) individuals engaged with healthcare - HR = 0.14, 95% CIs = 0.13-0.16). However, Omicron is disrupting these associations due to immune escape resulting in smaller effect sizes for both measures. 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.

4.
BMC Infect Dis ; 22(1): 270, 2022 Mar 20.
Article in English | MEDLINE | ID: covidwho-1745481

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.


Subject(s)
COVID-19 , Viral Vaccines , COVID-19/prevention & control , COVID-19 Vaccines , Humans , SARS-CoV-2/genetics
5.
Clin Epidemiol ; 13: 935-940, 2021.
Article in English | MEDLINE | ID: covidwho-1731645

ABSTRACT

Testing for SARS-CoV-2 internationally has focused on COVID-19 diagnosis among symptomatic individuals using reverse transcriptase polymerase chain reaction (PCR) tests. Recently, however, SARS-CoV-2 antigen rapid lateral flow tests (LFT) have been rolled out in several countries for testing asymptomatic individuals in public health programmes. Validation studies for LFT have been largely cross-sectional, reporting sensitivity, specificity and predictive values of LFT relative to PCR. However, because PCR detects genetic material left behind for a long period when the individual is no longer infectious, these statistics can under-represent the sensitivity of LFT for detecting infectious individuals, especially when sampling asymptomatic populations. LFTs (intended to detect individuals shedding SARS-CoV-2 antigens) validated against PCR (intended to diagnose infection) are not reporting against a gold standard of equivalent measurements. Instead, these validation studies have reported relative performance statistics that need recalibrating to the purpose for which LFT is being used. We present an approach to this recalibration. We derive a formula for recalibrating relative performance statistics from LFT vs PCR validation studies to give likely absolute sensitivity of LFT for detecting individuals who are shedding shedding SARS-CoV-2 antigens. We contrast widely reported apparent sensitivities of LFT with recalibrated absolute sensitivity for detecting individuals shedding SARS-CoV-2 antigens. After accounting for within-individual viral kinetics and epidemic dynamics within asymptomatic populations we show that a highly performant test for SARS-CoV-2 antigen should show LFT-to-PCR relative sensitivity of less than 50% in conventional validation studies, which after re-calibration would be an absolute sensitivity of more than 80%. Further studies are needed to ascertain the absolute sensitivity of LFT as a test of infectiousness in COVID-19 responses. These studies should include longitudinal series of LFT and PCR, ideally in cohorts sampled from both contacts of cases and the general population.

6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-322998

ABSTRACT

Introduction: Care homes have been severely affected by the SARS-CoV-2 pandemic. Rapid antigen testing could identify most SARS-CoV-2 infected staff and visitors before they enter homes. We explored implementation of staff and visitor testing protocols using lateral flow devices (LFDs). Methods: An evaluation of a SARS-CoV-2 LFD based testing protocol in 11 care homes in Liverpool, UK, including staff and visitor testing, plus a qualitative exploratory study in 9 of these homes. The proportion of pilot homes with outbreaks, and outbreak size, were compared to non-pilot homes in Liverpool. Adherence to testing protocols was evaluated. Fifteen staff were interviewed, and transcript data were thematically coded using an iterative analysis to identify and categorize factors influencing testing implementation. Results: 1638 LFD rapid tests were performed on 407 staff. Protocol adherence was poor with 8.6% of staff achieving &gt;75% protocol adherence, and 25.3% achieving ≥50%. Six care homes had outbreaks during the study. Compared to non-pilot care homes, there was no evidence of significant difference in the proportion of homes with outbreaks, or the size of outbreaks. Qualitative data showed difficulty implementing testing strategies due to excessive work burden. Factors influencing adherence related to test integration and procedural factors, socio-economic factors, cognitive overload, and the emotional value of testing. Conclusion: Implementation of staff and visitor care home LFD testing protocols was poorly adhered to and did not reduce the number or scale of COVID-19 outbreaks. More focus is needed on the contextual and behavioural factors that influence protocol adherence.<br>

7.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-310909

ABSTRACT

Background: The Innova SARS-CoV-2 antigen rapid lateral flow test (LFT) offers fast detection of COVID-19 cases. This study assesses the performance of LFT in the general population attending asymptomatic testing centres.Methods: Observational cohort study to compare LFT with reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) results based on two self-administrated swab samples per participant taken within minutes among individuals declaring no classic symptoms, attending asymptomatic testing sites in Liverpool, UK, between 6th and 29th of November 2020.Findings: 5869 individuals attended 48 testing sites in Liverpool. The relative sensitivity of LFT versus RT-qPCR, excluding void tests, was 40∙0% (95% CI: 28∙5 to 52∙4;28/70). The specificity was 99∙9% (99∙8 to 99∙99;5431/5434), positive predictive value was 90∙3% (74∙2 to 98∙0;28/31) and negative predictive value was 99∙2% (99∙0 to 99∙4;5431/5473). For cases with RT-qPCR cycle threshold CT <18∙3 (approximate viral loads > 10 6 RNA copies/ml), sensitivity was 90∙9% (58∙7 to 99∙8;10/11), for CT <24∙4 (viral load > 10 4 RNA copies/ml), sensitivity was 69∙4% (51∙9 to 83∙7;25/36), and for CT >24∙4 (viral load <10 4 RNA copies/ml), sensitivity was 9∙7% (1∙9 to 23∙7;3/34).Interpretation: Innova LFT is a helpful tool for identifying infections among people who declare no symptoms of COVID-19, particularly those with high viral load and so more likely to infect others. The number of cases with lower CT (indicating higher viral load) missed by LFT, although small, should be considered, with due caution over using single LFT in high-consequence settings. Clear and accurate communication with the public about how to interpret test results is important. Further research is needed to understand how infectiousness is reflected in the viral antigen shedding detected by LFT versus the viral loads approximated by RT-qPCR.Funding: This evaluation was commissioned by the UK Department of Health and Social Care.Declaration of Interests: This evaluation was commissioned by the UK Department of Health and Social Care. IEB, MGF, MGS, DMH, GB and CPC received grant funding from the UK Department of Health and Social Care to evaluate LFT in the Liverpool pilot discussed in this article. IEB reports fees from AstraZeneca as chief data scientist adviser via Liverpool University and a senior investigator grant from the National Institute for Health Research (NIHR) outside the submitted work. MGS is Chair of the Infectious Disease Scientific Advisory Board and a minority shareholder in Integrum Scientific LLC, Greensboro, NC, USA, a company that has interests in COVID-19 testing but not with lateral flow technology, and reports grants from the NIHR, the Medical Research Council, and the Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool.Ethics Approval Statement: The University of Liverpool provided secondary data analysis as part of a UK national service evaluation with data collection by the UK Department of Health and Social Care (DHSC;Sponsor) As per the National Health Service (NHS) Research Authority guidelines, this work did not require ethical approval.

8.
J Public Health (Oxf) ; 2022 Feb 04.
Article in English | MEDLINE | ID: covidwho-1684779

ABSTRACT

BACKGROUND: Twice weekly lateral flow tests (LFTs) for secondary school children was UK Government policy from 8 March 2021. We evaluate use of LFTs (both supervised at test centres, and home test kits) in school-aged children in Cheshire and Merseyside. METHODS: We report (i) number of LFT positives (ii) proportion of LFT positive with confirmatory reverse transcription polymerase chain reaction (PCR) test within 2 days, and (iii) agreement between LFT-positive and confirmatory PCR, and dependence of (i-iii) on COVID-19 prevalence. FINDINGS: 1 248 468 LFTs were taken by 211 255 12-18 years old, and 163 914 by 52 116 5-11 years old between 6 November 2020 and 31 July 2021. Five thousand three hundred and fourteen (2.5%) 12-18 years old and 1996 (3.8%) 5-11 years old returned LFT positives, with 3829 (72.1%) and 1535 (76.9%) confirmatory PCRs, and 3357 (87.7%) and 1383 (90.1%) confirmatory PCR-positives, respectively.Monthly proportions of LFT positive with PCR negative varied between 4.7% and 35.3% in 12-18 years old (corresponding proportion of all tests positive: 9.7% and 0.3%).Deprivation and non-White ethnicity were associated with reduced uptake of confirmatory PCR. INTERPRETATION: Substantial inequalities in confirmatory testing need more attention to avoid further disadvantage through education loss. When prevalence is low additional measures, including confirmatory testing, are needed. Local Directors of Public Health taking more control over schools testing may be needed. FUNDING: DHSC, MRC, NIHR, EPSRC.

9.
The Lancet ; 398, 2021.
Article in English | ProQuest Central | ID: covidwho-1537173

ABSTRACT

Background In 2020, a second wave of COVID-19 cases unevenly affected places in England, and different levels of tiered restrictions were introduced in different parts of the country. Previous research has examined the impact of national lockdowns on transmission. We aimed to examine the differences in the effect of localised restrictions on COVID-19 cases and how these differences varied by deprivation. Methods We examined the transmission impact of tier 3 restrictions using data on weekly reported COVID-19 cases, adjusted for case-detection rates for 7201 neighbourhoods in England. We identified areas that entered tier 3 restrictions in October and December, 2020, constructed a synthetic control group of places under tier 2 restrictions, and compared changes in weekly infections over a 4-week period. Sufficiently granular data on deaths were not available to investigate excess mortality. We analysed whether this effect varied by level of deprivation and the prevalence of a new variant (B.1.1.7), by stratifying the synthetic control weighting by subgroups and then including an interaction term between subgroup and intervention in the regression model. We used the English Indices of Multiple Deprivation and its tertiles in the stratification to measure deprivation. We tested the spatial spillover effects excluding tier 2 areas within 20 km of tier 3 areas. Ethics approval was not needed. Findings The introduction of tier 3 restrictions was associated with a reduction in infections of 14% (95% CI 10–19) in October and of 20% (13–29) in December, or with a reduction in absolute number of total infections of 3536 (95% CI 2880–4192) in October and of 92 732 (49 776–135 688) in December, compared with what would have been expected under tier 2 restrictions. The effects were similar across levels of deprivation and by the prevalence of the new variant. We found smaller effects with high non-significant p values when excluding boundary areas. Interpretation Compared to tier 2 restrictions, restrictions on hospitality and meeting outdoors in tier 3 areas had a moderate effect on transmission and these restrictions did not appear to increase inequalities in COVID-19 cases. Limitations include a lack of specificity as to which of the main restrictions contributed to this effect, potentially biases from the crude measure of case-detection rates applied, and the lack of controls for individual or household characteristics in this ecological analysis. Funding National Institute for Health Research (NIHR).

10.
Thorax ; 2021 Nov 22.
Article in English | MEDLINE | ID: covidwho-1528562

ABSTRACT

PURPOSE: To prospectively validate two risk scores to predict mortality (4C Mortality) and in-hospital deterioration (4C Deterioration) among adults hospitalised with COVID-19. METHODS: Prospective observational cohort study of adults (age ≥18 years) with confirmed or highly suspected COVID-19 recruited into the International Severe Acute Respiratory and emerging Infections Consortium (ISARIC) WHO Clinical Characterisation Protocol UK (CCP-UK) study in 306 hospitals across England, Scotland and Wales. Patients were recruited between 27 August 2020 and 17 February 2021, with at least 4 weeks follow-up before final data extraction. The main outcome measures were discrimination and calibration of models for in-hospital deterioration (defined as any requirement of ventilatory support or critical care, or death) and mortality, incorporating predefined subgroups. RESULTS: 76 588 participants were included, of whom 27 352 (37.4%) deteriorated and 12 581 (17.4%) died. Both the 4C Mortality (0.78 (0.77 to 0.78)) and 4C Deterioration scores (pooled C-statistic 0.76 (95% CI 0.75 to 0.77)) demonstrated consistent discrimination across all nine National Health Service regions, with similar performance metrics to the original validation cohorts. Calibration remained stable (4C Mortality: pooled slope 1.09, pooled calibration-in-the-large 0.12; 4C Deterioration: 1.00, -0.04), with no need for temporal recalibration during the second UK pandemic wave of hospital admissions. CONCLUSION: Both 4C risk stratification models demonstrate consistent performance to predict clinical deterioration and mortality in a large prospective second wave validation cohort of UK patients. Despite recent advances in the treatment and management of adults hospitalised with COVID-19, both scores can continue to inform clinical decision making. TRIAL REGISTRATION NUMBER: ISRCTN66726260.

11.
PLoS One ; 16(9): e0257051, 2021.
Article in English | MEDLINE | ID: covidwho-1403310

ABSTRACT

It has been widely observed that adult men of all ages are at higher risk of developing serious complications from COVID-19 when compared with women. This study aimed to investigate the association of COVID-19 positivity and severity with estrogen exposure in women, in a population based matched cohort study of female users of the COVID Symptom Study application in the UK. Analyses included 152,637 women for menopausal status, 295,689 women for exogenous estrogen intake in the form of the combined oral contraceptive pill (COCP), and 151,193 menopausal women for hormone replacement therapy (HRT). Data were collected using the COVID Symptom Study in May-June 2020. Analyses investigated associations between predicted or tested COVID-19 status and menopausal status, COCP use, and HRT use, adjusting for age, smoking and BMI, with follow-up age sensitivity analysis, and validation in a subset of participants from the TwinsUK cohort. Menopausal women had higher rates of predicted COVID-19 (P = 0.003). COCP-users had lower rates of predicted COVID-19 (P = 8.03E-05), with reduction in hospital attendance (P = 0.023). Menopausal women using HRT or hormonal therapies did not exhibit consistent associations, including increased rates of predicted COVID-19 (P = 2.22E-05) for HRT users alone. The findings support a protective effect of estrogen exposure on COVID-19, based on positive association between predicted COVID-19 with menopausal status, and negative association with COCP use. HRT use was positively associated with COVID-19, but the results should be considered with caution due to lack of data on HRT type, route of administration, duration of treatment, and potential unaccounted for confounders and comorbidities.


Subject(s)
COVID-19/epidemiology , Estrogen Replacement Therapy , Estrogens/metabolism , Menopause/metabolism , Adult , Cohort Studies , Comorbidity , Female , Humans , Middle Aged , Risk Factors , United Kingdom
12.
Journal of Epidemiology and Community Health ; 75(Suppl 1):A3, 2021.
Article in English | ProQuest Central | ID: covidwho-1394144

ABSTRACT

BackgroundAsymptomatic transmission of SARS-CoV-2 poses a significant burden on managing the spread of COVID-19. Few studies have evaluated the impact of testing for asymptomatic COVID-19 among large populations or whole cities using empirical data. No study to our knowledge has considered if such interventions result in or exacerbate existing socioeconomic inequalities. The aim of our 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 in Liverpool between 6th November 2020 and 31st January 2021.MethodsLinked pseudonymised records for asymptomatic residents in Liverpool (UK) 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 (CIPHA) data resource. Bayesian Hierarchical Poisson Besag, York, and Mollié models were used to estimate ecological associations for uptake and positivity of testing.Results214 525 residents (43%) received a LFT identifying 5557 individuals as positive cases of COVID-19 (1.3%). 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 and repeat testing 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.ConclusionOur study provides the first substantial evidence on inequalities involved in large-scale asymptomatic rapid testing of populations for SARS-CoV-2. Large-scale voluntary asymptomatic community testing saw social, ethnic, and spatial inequalities in an ‘inverse care’ pattern, but with an added digital exclusion factor. While test uptake was popular, there was a disconnect between the populations accessing testing and those experiencing harms relating to COVID-19. 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.

13.
Journal of Epidemiology and Community Health ; 75(Suppl 1):A1, 2021.
Article in English | ProQuest Central | ID: covidwho-1394140

ABSTRACT

BackgroundIn 2020, a second wave of COVID-19 cases unevenly affected places in England leading to the introduction of a tiered system of controls with different geographical areas subject to different levels of restrictions. Whilst previous research has examined the impact of national lockdowns on transmission, there has been limited research examining the marginal effect of differences in localised restrictions or how these effects vary between socioeconomic contexts. We therefore examined how Tier 3 restrictions in England implemented between October-December 2020, which included additional restrictions on the hospitality sector and people meeting outdoors affected COVID-19 case rates, compared to Tier 2 restrictions, and how these effects varied by level of deprivation.MethodsWe used data on weekly reported COVID-19 cases for 7201 neighbourhoods in England and adjusted these for changing case-detection rates to provide an estimate of weekly SARS-CoV-2 infections in each neighbourhood. We identified those areas that entered Tier 3 restrictions at two time points in October and December, and constructed a synthetic control group of similar places that had entered Tier 2 restrictions, using calibration weights to match them on a wide range of covariates that may influence transmission. We then compared the change in weekly infections between those entering Tier 3 to the synthetic control group to estimate the proportional reduction of cases resulting from Tier 3 restrictions compared to Tier 2 restrictions, over a 4-week period. We further used interaction analysis to estimate whether this effect differed based on the level of socioeconomic deprivation in each neighbourhood and whether effects were modified by the prevalence of a new more infectious variant of SARS-CoV-2 (B.1.1.7) in each area.ResultsThe introduction of Tier 3 restrictions in October and December was associated with a 14% (95% CI 10% to 19%) and 20% (95% CI 13% to 29%) reduction in infections respectively, compared to the rates expected if only Tier 2 restrictions had been in place in those areas. We found that effects were similar across levels of deprivation and limited evidence that Tier 3 restrictions had a greater effect in areas where the new more infectious variant was more prevalent.DiscussionCompared to Tier 2 restrictions, additional restrictions on hospitality and meeting outdoors introduced in Tier 3 areas in England had a moderate effect on transmission and these restrictions did not appear to increase inequalities.

15.
Age Ageing ; 50(6): 1868-1875, 2021 11 10.
Article in English | MEDLINE | ID: covidwho-1316792

ABSTRACT

INTRODUCTION: Care homes have been severely affected by the SARS-CoV-2 pandemic. Rapid antigen testing could identify most SARS-CoV-2 infected staff and visitors before they enter homes. We explored implementation of staff and visitor testing protocols using lateral flow devices (LFDs). METHODS: An evaluation of a SARS-CoV-2 LFD-based testing protocol in 11 care homes in Liverpool, UK, including staff and visitor testing, plus a qualitative exploratory study in nine of these homes. The proportion of pilot homes with outbreaks, and outbreak size, were compared to non-pilot homes in Liverpool. Adherence to testing protocols was evaluated. Fifteen staff were interviewed, and transcript data were thematically coded using an iterative analysis to identify and categorize factors influencing testing implementation. RESULTS: In total, 1,638 LFD rapid tests were performed on 407 staff. Protocol adherence was poor with 8.6% of staff achieving >75% protocol adherence, and 25.3% achieving $\ge$50%. Six care homes had outbreaks during the study. Compared to non-pilot care homes, there was no evidence of significant difference in the proportion of homes with outbreaks, or the size of outbreaks. Qualitative data showed difficulty implementing testing strategies due to excessive work burden. Factors influencing adherence related to test integration and procedural factors, socio-economic factors, cognitive overload and the emotional value of testing. CONCLUSION: Implementation of staff and visitor care home LFD testing protocols was poorly adhered to and consequently did not reduce the number or scale of COVID-19 outbreaks. More focus is needed on the contextual and behavioural factors that influence protocol adherence.


Subject(s)
COVID-19 , COVID-19 Testing , Disease Outbreaks/prevention & control , Humans , Pandemics , SARS-CoV-2
16.
BMJ ; 374: n1637, 2021 07 06.
Article in English | MEDLINE | ID: covidwho-1299224

ABSTRACT

OBJECTIVE: To assess the performance of the SARS-CoV-2 antigen rapid lateral flow test (LFT) versus polymerase chain reaction testing in the asymptomatic general population attending testing centres. DESIGN: Observational cohort study. SETTING: Community LFT pilot at covid-19 testing sites in Liverpool, UK. PARTICIPANTS: 5869 asymptomatic adults (≥18 years) voluntarily attending one of 48 testing sites during 6-29 November 2020. INTERVENTIONS: Participants were tested using both an Innova LFT and a quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) test based on supervised self-administered swabbing at testing sites. MAIN OUTCOME MEASURES: Sensitivity, specificity, and predictive values of LFT compared with RT-qPCR in an epidemic steady state of covid-19 among adults with no classic symptoms of the disease. RESULTS: Of 5869 test results, 22 (0.4%) LFT results and 343 (5.8%) RT-qPCR results were void (that is, when the control line fails to appear within 30 minutes). Excluding the void results, the LFT versus RT-qPCR showed a sensitivity of 40.0% (95% confidence interval 28.5% to 52.4%; 28/70), specificity of 99.9% (99.8% to 99.99%; 5431/5434), positive predictive value of 90.3% (74.2% to 98.0%; 28/31), and negative predictive value of 99.2% (99.0% to 99.4%; 5431/5473). When the void samples were assumed to be negative, a sensitivity was observed for LFT of 37.8% (26.8% to 49.9%; 28/74), specificity of 99.6% (99.4% to 99.8%; 5431/5452), positive predictive value of 84.8% (68.1% to 94.9%; 28/33), and negative predictive value of 93.4% (92.7% to 94.0%; 5431/5814). The sensitivity in participants with an RT-qPCR cycle threshold (Ct) of <18.3 (approximate viral loads >106 RNA copies/mL) was 90.9% (58.7% to 99.8%; 10/11), a Ct of <24.4 (>104 RNA copies/mL) was 69.4% (51.9% to 83.7%; 25/36), and a Ct of >24.4 (<104 RNA copies/mL) was 9.7% (1.9% to 23.7%; 3/34). LFT is likely to detect at least three fifths and at most 998 in every 1000 people with a positive RT-qPCR test result with high viral load. CONCLUSIONS: The Innova LFT can be useful for identifying infections among adults who report no symptoms of covid-19, particularly those with high viral load who are more likely to infect others. The number of asymptomatic adults with lower Ct (indicating higher viral load) missed by LFT, although small, should be considered when using single LFT in high consequence settings. Clear and accurate communication with the public about how to interpret test results is important, given the chance of missing some cases, even at high viral loads. Further research is needed to understand how infectiousness is reflected in the viral antigen shedding detected by LFT versus the viral loads approximated by RT-qPCR.


Subject(s)
COVID-19 Nucleic Acid Testing , COVID-19 Serological Testing , COVID-19/diagnosis , Carrier State/diagnosis , Carrier State/virology , Adult , COVID-19/complications , Cohort Studies , Female , Humans , Male , Pilot Projects , Predictive Value of Tests , ROC Curve , Reverse Transcriptase Polymerase Chain Reaction , United Kingdom
18.
Age Ageing ; 50(5): 1442-1444, 2021 09 11.
Article in English | MEDLINE | ID: covidwho-1226520

ABSTRACT

COVID-19 has devastated care homes. Point-of-care tests (POCTs), mainly using lateral flow devices (LFDs), have been deployed hurriedly without much consideration of their usability or impact on care workflow. Even after the pandemic, POCTs, particularly multiplex tests, may be an important control against spread of SARS-CoV-2 and other respiratory infections in care homes by enabling identification of cases. They should not, however, replace other infection control measures such as barrier methods and quarantine. Adherence to LFDs as implemented among care home staff is suboptimal. Other tests-such as point-of-care polymerase chain reaction and automated antigen tests-would also need to be accommodated into care home workflows to improve adherence. The up-front costs of POCTs are straightforward but additional costs, including staffing preparation and reporting processes and the impacts of false positive and negative tests on absence rates and infection days, are more complex and as yet unquantified. A detailed appraisal is needed as the future of testing in care homes is considered.


Subject(s)
COVID-19 , Humans , Pandemics , Point-of-Care Testing , Policy , SARS-CoV-2
19.
Lancet Reg Health Eur ; 6: 100107, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1225323

ABSTRACT

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.

20.
Science ; 372(6542): 571-572, 2021 05 07.
Article in English | MEDLINE | ID: covidwho-1219275
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