Andrew Copas's research while affiliated with UCL Eastman Dental Institute and other places

Publications (395)

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Background Cluster-randomized trials (CRTs) involve randomizing groups of individuals (e.g. hospitals, schools or villages) to different interventions. Various approaches exist for analysing CRTs but there has been little discussion around the treatment effects (estimands) targeted by each. Methods We describe the different estimands that can be a...
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Background Older age and frailty are risk factors for poor clinical outcomes following SARS-CoV-2 infection. As such, COVID-19 vaccination has been prioritised for individuals with these factors, but there is concern that immune responses might be impaired due to age-related immune dysregulation and comorbidity. We aimed to study humoral and cellul...
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Background Residents and staff in long-term care facilities have been prioritised for vaccination against SARS-CoV-2, but data on potential waning of vaccine effectiveness and the effect of booster doses in this vulnerable population are scarce. We aimed to evaluate effectiveness of one, two, and three vaccine doses against infection and severe cli...
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Background: Antenatal detection and management of small for gestational age (SGA) is a strategy to reduce stillbirth. Large observational studies provide conflicting results on the effect of the Growth Assessment Protocol (GAP) in relation to detection of SGA and reduction of stillbirth; to the best of our knowledge, there are no reported randomis...
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The observed epidemiology of SARS-CoV-2 in sub-Saharan Africa has varied greatly from that in Europe and the United States, with much lower reported incidence. Population-based studies are needed to estimate true cumulative incidence of SARS-CoV-2 to inform public health interventions. This study estimated SARS-CoV-2 seroprevalence in four selected...
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We studied humoral and cellular immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 152 long-term care facility staff and 124 residents over a prospective 4-month period shortly after the first wave of infection in England. We show that residents of long-term care facilities developed high and stable levels of antibodie...
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Background: The National Surveys of Sexual Attitudes and Lifestyles COVID study (Natsal-COVID) was designed to understand the impact of COVID-19 on Britain’s sexual and reproductive health (SRH). Natsal-COVID Wave 1 survey and qualitative follow-up interviews were conducted in 2020. The Wave 2 survey was designed to capture one-year prevalence esti...
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Introduction Dans un essai randomisé en cluster en « stepped-wedge » (ERC-SW), la randomisation ne détermine pas l'intervention reçue par le cluster mais la séquence selon laquelle l'intervention sera implémentée au sein des clusters participants. A la fin de l'essai, tous les clusters reçoivent l'intervention ce qui constitue le principal atout de...
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Background The SARS-CoV-2 omicron variant (B.1.1.529) is highly transmissible, but disease severity appears to be reduced compared with previous variants such as alpha and delta. We investigated the risk of severe outcomes following infection in residents of long-term care facilities. Methods We did a prospective cohort study in residents of long-...
Preprint
Objectives To investigate how differential access to key interventions to reduce sexually transmitted infections (STI), HIV, and their sequelae changed during the COVID-19 pandemic. Methods British participants (18-59y) completed a cross-sectional web survey one year (March to April 2021) after the initial lockdown in Britain. Quota-based sampling...
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Introduction residents of long-term care facilities (LTCFs) are at high risk of adverse outcomes from SARS-CoV-2. We aimed to estimate the vaccine effectiveness (VE) of one and two doses of BNT162b2 and ChAdOx-1 against SARS CoV-2 infection and COVID-19-related death in residents of LTCFs. Methods this observational study used testing, vaccination...
Preprint
Third dose COVID-19 vaccines are being deployed widely but their efficacy has not been assessed adequately in vulnerable elderly people who exhibit suboptimal responses after primary series vaccination. We studied spike-specific immune responses in 341 staff and residents in long-term care facilities (LTCF) who received an mRNA vaccine following du...
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General population studies have shown strong humoral response following SARS-CoV-2 vaccination with subsequent waning of anti-spike antibody levels. Vaccine-induced immune responses are often attenuated in frail and older populations, but published data are scarce. We measured SARS-CoV-2 anti-spike antibody levels in Long-Term Care Facility residen...
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Introduction: Globally, tuberculosis (TB) is a leading cause of death in women of reproductive age and there is high risk of reactivation of latent tuberculosis infection (LTBI) in pregnancy. The uptake of routine screening of migrants for LTBI in the UK in primary care is low. Antenatal care is a novel setting which could improve uptake and can l...
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Objectives Nosocomial transmission of SARS-CoV-2 has been a significant cause of mortality in National Health Service (NHS) hospitals during the COVID-19 pandemic. The COG-UK Consortium Hospital-Onset COVID-19 Infections (COG-UK HOCI) study aims to evaluate whether the use of rapid whole-genome sequencing of SARS-CoV-2, supported by a novel probabi...
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Objective To explore challenges in recruitment and intervention implementation in recent stepped-wedge cluster randomized trials (SW-CRTs). Study design and setting We searched PubMed to identify primary reports of SW-CRTs (2019–2020). Two reviewers independently screened studies and extracted data from each report. Recruitment challenge was defin...
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Background: Britain’s National Surveys of Sexual Attitudes and Lifestyles (Natsal) have been undertaken decennially since 1990 and provide a key data source underpinning sexual and reproductive health (SRH) policy. The COVID-19 pandemic disrupted many aspects of sexual lifestyles, triggering an urgent need for population-level data on sexual behavi...
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Effective decision making from randomised controlled clinical trials relies on robust interpretation of the numerical results. However, the language we use to describe clinical trials can cause confusion in both trial design and in comparing results across trials. Acceptability curve estimation (ACE) aids comparison between trials (even where of di...
Preprint
Effective decision making from randomised controlled clinical trials relies on robust interpretation of the numerical results. However, the language we use to describe clinical trials can cause confusion in both trial design and in comparing results across trials. Acceptability curve estimation (ACE) aids comparison between trials (even where of di...
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Intimate relationships are ubiquitous and exert a strong influence on health. Widespread disruption to them may impact wellbeing at a population level. We investigated the extent to which the first COVID-19 lockdown (March 2020) affected steady relationships in Britain. In total, 6,654 participants aged 18-59 years completed a web-panel survey (Jul...
Preprint
Background Long-term care facilities (LTCF) have been prioritised for vaccination, but data on potential waning of vaccine effectiveness (VE) and the impact of booster doses in this vulnerable population remains scarce. Methods We included residents and staff from 331 LTCFs enrolled in VIVALDI ( ISRCTN 14447421 ), who underwent routine PCR testing...
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There is limited evidence on the cost and cost-effectiveness of cash transfer programmes to improve maternal and child health in Kenya and other sub-Saharan African countries. This article presents the economic evaluation results of the Afya trial, assessing the costs, cost-effectiveness and equity impact of a demand-side financing intervention tha...
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Background Antiretroviral therapy (ART) through universal test and treat (UTT) and HIV pre-exposure prophylaxis (PrEP) substantially reduces HIV-related mortality, morbidity and incidence. Effective individual-level prevention modalities have not translated into population-level impact in southern Africa due to sub-optimal coverage among adolescent...
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Background: Anaemia in pregnancy remains prevalent in Nepal and causes severe adverse health outcomes. Methods: This non-blinded cluster-randomised controlled trial in the plains of Nepal has two study arms: (1) Control: routine antenatal care (ANC); (2) Home visiting, iron supplementation, Participatory Learning and Action (PLA) groups, plus ro...
Preprint
Introduction Viral sequencing of SARS-CoV-2 has been used for outbreak investigation, but there is limited evidence supporting routine use for infection prevention and control (IPC) within hospital settings. Methods We conducted a prospective non-randomised trial of sequencing at 14 acute UK hospital trusts. Sites each had a 4-week baseline data-c...
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Objectives Physical distancing as a non-pharmaceutical intervention aims to reduce interactions between people to prevent SARS-CoV-2 transmission. Intimate physical contact outside the household (IPCOH) may expand transmission networks by connecting households. We aimed to explore whether intimacy needs impacted adherence to physical distancing fol...
Preprint
Background General population studies have shown strong humoral response following SARS-CoV-2 vaccination with subsequent waning of anti-spike antibody levels. Vaccine-induced immune responses are often attenuated in frail and older populations such as Long-Term Care Facility (LTCF) residents but published data are scarce. Methods VIVALDI is a pro...
Preprint
Background Recently there has been a rapid, global increase in SARS-CoV-2 infections associated with the Omicron variant (B.1.1.529). Although severity of Omicron cases may be reduced, the scale of infection suggests hospital admissions and deaths may be substantial. Definitive conclusions about disease severity require evidence from populations wi...
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Objectives Given high maternal and child mortality rates, we assessed the impact of conditional cash transfers (CCTs) to retain women in the continuum of care (antenatal care (ANC), delivery at facility, postnatal care (PNC) and child immunisation). Design We conducted an unblinded 1:1 cluster-randomised controlled trial. Setting 48 health facili...
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Background The COVID-19 pandemic has affected sexual and reproductive health (SRH) service use and unmet need, but the impact is unknown. We aimed to determine the proportion of participants reporting sexual risk behaviours, SRH service use and unmet need, and to assess remote sexually transmitted infection (STI) testing service use after the first...
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Objectives Physical restrictions imposed to combat COVID-19 dramatically altered sexual lifestyles but the specific impacts on sexual behaviour are still emerging. We investigated physical and virtual sexual activities, sexual frequency and satisfaction in the 4 months following lockdown in Britain in March 2020 and compared with pre-lockdown. Met...
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Background: Long-term care facilities (LTCFs) have reported high SARS-CoV-2 infection rates and related mortality, but the proportion of infected people among those who have survived, and duration of the antibody response to natural infection, is unknown. We determined the prevalence and stability of nucleocapsid antibodies (the standard assay for...
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We describe the impact of changing epidemiology and vaccine introduction on characteristics of COVID-19 outbreaks in 330 long-term care facilities (LTCF) in England between November 2020 and June 2021. As vaccine coverage in LTCF increased and national incidence declined, the total number of outbreaks and outbreak severity decreased across the LTCF...
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Introduction The WHO recommends community mobilisation with women’s groups practising participatory learning and action (PLA) to improve neonatal survival in high-mortality settings. This intervention has not been evaluated at scale with government frontline workers. Methods We did a pragmatic cluster non-randomised controlled trial of women’s gro...
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Background The UK's National Surveys of Sexual Attitudes and Lifestyles (Natsal) have been done every 10 years since 1990, and provide a key data source to underpin sexual and reproductive health policy. The COVID-19 pandemic disrupted many lifestyle aspects, triggering an urgent need for population-level data on sexual behaviour, relationships, an...
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Using data from the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3) we examined associations between salivary testosterone (Sal-T) and sexual function and behavior. Single morning saliva samples were self-collected from a subsample of participants aged 18-74 years and analyzed using mass spectrometry. 1,599 men and 2,123...
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Background Sharing trial results with participants is an ethical imperative but often does not happen. We tested an Enhanced Webpage versus a Basic Webpage, Mailed Printed Summary versus no Mailed Printed Summary, and Email List Invitation versus no Email List Invitation to see which approach resulted in the highest patient satisfaction with how th...
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Objectives : Recently emerging SARS-CoV-2 variants have been associated with an increased rate of transmission within the community. We sought to determine whether this also resulted in increased transmission within hospitals. Methods : We collected viral sequences and epidemiological data of patients with community and healthcare associated SARS-...
Preprint
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Background Long Term Care Facilities (LTCF) have reported high SARS-CoV-2 infection rates and related mortality, but the proportion infected amongst survivors and duration of the antibody response to natural infection is unknown. We determined the prevalence and stability of nucleocapsid antibodies - the standard assay for detection of prior infect...
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Background SARS-CoV-2 lineage B.1.1.7 has been associated with an increased rate of transmission and disease severity among subjects testing positive in the community. Its impact on hospitalised patients is less well documented. Methods We collected viral sequences and clinical data of patients admitted with SARS-CoV-2 and hospital-onset COVID-19...
Preprint
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Long term care facilities (LTCF) provide residential and/or nursing care support for frail and elderly people and many have suffered from a high prevalence of SARS-CoV-2 infection. Although mortality rates have been high in LTCF residents there is little information regarding the features of SARS-CoV-2-specific immunity after infection in this sett...
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Background: Britain’s National Surveys of Sexual Attitudes and Lifestyles (Natsal) have been undertaken decennially since 1990 and provide a key data source underpinning sexual and reproductive health (SRH) policy. The COVID-19 pandemic disrupted many aspects of sexual lifestyles, triggering an urgent need for population-level data on sexual behavi...
Article
Background: Britain’s National Surveys of Sexual Attitudes and Lifestyles (Natsal) have been undertaken decennially since 1990 and provide a key data source underpinning sexual and reproductive health (SRH) policy. The COVID-19 pandemic disrupted many aspects of sexual lifestyles, triggering an urgent need for population-level data on sexual behavi...
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Full-text available
Reports suggest an increased risk of tuberculosis (TB) in people with chronic airway diseases (CADs) such as chronic obstructive pulmonary disease (COPD), but evidence has not been systematically reviewed. We performed a systematic review by searching MEDLINE and Embase for studies published from 1 January 1993 to 15 January 2021 reporting the asso...
Preprint
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Objective: To assess accelerated partner therapy (APT) as a contact tracing intervention for people with chlamydia. Design: Cross-over cluster-randomised controlled trial. Setting: 17 sexual health clinics (clusters) in the United Kingdom, 2018-2019. Participants: Heterosexual people aged over 16 years with a positive Chlamydia trachomatis test res...
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Background Residents of long-term care facilities (LTCFs) have been prioritised for COVID-19 vaccination because of the high COVID-19 mortality in this population. Several countries have implemented an extended interval of up to 12 weeks between the first and second vaccine doses to increase population coverage of single-dose vaccination. We aimed...
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Overstating the impact of interventions through incomplete or inaccurate reporting can lead to inappropriate scale-up of interventions with low impact. Accurate reporting of the impact of interventions is of great importance in global health research to protect scarce resources. In global health, the cluster randomised trial design is commonly used...
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There are sometimes cost, scientific, or logistical reasons to allocate individuals unequally in an individually randomized trial. In cluster randomized trials we can allocate clusters unequally and/or allow different cluster size between trial arms. We consider parallel group designs with a continuous outcome, and optimal designs that require the...
Preprint
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Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) lineage B.1.1.7 has been associated with an increased rate of transmission and disease severity among subjects testing positive in the community. Its impact on hospitalised patients is less well documented. Methods We collected viral sequences and clinical data of patients admi...
Preprint
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Objectives: Men who have sex with men (MSM) are disproportionately affected by sexually transmitted infections (STIs). Partner notification (PN) to identify, test and treat sex partners of MSM with bacterial STIs is challenging because MSM often report larger numbers of sex partners and a higher proportion of one-off partners who may be difficult t...
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Background SARS-CoV-2 infection represents a major challenge for long-term care facilities (LTCFs) and many residents and staff are seropositive following persistent outbreaks. We aimed to investigate the association between the SARS-CoV-2 antibody status at baseline and subsequent infection in this population. Methods We did a prospective cohort...
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Background The effectiveness of SARS-CoV-2 vaccines in older adults living in long-term care facilities is uncertain. We investigated the protective effect of the first dose of the Oxford-AstraZeneca non-replicating viral-vectored vaccine (ChAdOx1 nCoV-19; AZD1222) and the Pfizer-BioNTech mRNA-based vaccine (BNT162b2) in residents of long-term care...
Preprint
Full-text available
Background Anaemia in pregnancy remains prevalent in Nepal and causes severe adverse health outcomes. Methods This non-blinded cluster-randomized controlled trial in the plains of Nepal has two study arms: 1) Control: routine antenatal care (ANC); 2) Home visiting, iron supplementation, Participatory Learning and Action (PLA) groups, plus routine A...
Preprint
Introduction Nosocomial transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been a significant cause of mortality in National Health Service (NHS) hospitals during the coronavirus disease 2019 (COVID-19) pandemic. The aim of this study is to evaluate the impact of rapid whole genome sequencing of SARS-CoV-2, supported b...
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Background An estimated 463 million people globally have diabetes, with the prevalence growing in low-and middle-income settings, such as Bangladesh. Given the need for context-appropriate interventions to prevent type 2 diabetes mellitus (T2DM), the ‘Diabetes: Community-led Awareness, Response and Evaluation’ (D:Clare) trial will rigorously evalua...
Preprint
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Background The effectiveness of SARS-CoV-2 vaccines in frail older adults living in Long-Term Care Facilities (LTCFs) is uncertain. We estimated protective effects of the first dose of ChAdOx1 and BNT162b2 vaccines against infection in this population. Methods Cohort study comparing vaccinated and unvaccinated LTCF residents in England, undergoing...
Preprint
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Background SARS-CoV-2 infection represents a major challenge for Long Term Care Facilities (LTCFs) and many residents and staff are now sero-positive following persistent outbreaks. We investigated the relationship between the presence of SARS-CoV-2 specific antibodies and subsequent infection in this population. Methods Prospective cohort study of...
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Background The use of electronic patient records for assessing outcomes in clinical trials is a methodological strategy intended to drive faster and more cost-efficient acquisition of results. The aim of this manuscript was to outline the data collection and management considerations of a maternity and perinatal clinical trial using data from elect...
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Background Cluster randomised trials, like individually randomised trials, may benefit from a baseline period of data collection. We consider trials in which clusters prospectively recruit or identify participants as a continuous process over a given calendar period, and ask whether and for how long investigators should collect baseline data as par...
Preprint
Full-text available
Background The use of electronic patient records for assessing outcomes in clinical trials is a methodological strategy intended to drive faster and more cost-efficient acquisition of results. The aim of this manuscript was to outline the data collection and management considerations of a maternity and perinatal clinical trial using data from elect...
Article
Global infection and mortality rates from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are disproportionately high in certain populations, including amongst older people. Care home residents are frequently exposed to infection due to contact with staff and other residents, and are highly susceptible to infection due to their age and...