COCOS trial: COrticosteroids for COVID-19-induced loss of Smell-protocol for a single-centred, double-blind, randomised, placebo-controlled trial

Introduction
Hyposmia and anosmia are common in COVID-19. Most patients regain normal smell within 4 weeks, but severe loss of smell persists roughly in 20% after 2 months and may last up to a year or longer. These persistent smell disorders greatly influence daily life. It is hypothesised that COVID-19 induces inflammation around the olfactory nerve and in the olfactory pathway, leading to smell disorders. Corticosteroids might reduce this local inflammatory response and improve smell.

Methods and analysis
We will conduct a single-centre, randomised, placebo-controlled trial to determine the efficacy of a short high-dose treatment of oral prednisolone for persistent loss of smell after COVID-19 in the early phase. We will include 116 patients with persistent ( >4 weeks) loss of smell within 12 weeks of COVID-19 diagnosis, based on a positive PCR/antigen test. One group receives 40 mg of prednisolone for 10 days and the other group receives matching placebo treatment. In addition, all patients will perform smell training for 12 weeks. The primary outcome is objective olfactory function measured by means of sniffin’ sticks test. Secondary outcomes are objective gustatory function by means of taste strips test and subjective taste and smell ability, trigeminal sensations, quality of life and nasal symptoms, measured by three questionnaires. These outcomes will be measured at inclusion before treatment and 12 weeks later.

Ethics and dissemination
The Institutional Review Board of the University Medical Center Utrecht approved the research protocol (21-635/G-D, October 2021). The trial results will be shared in peer-reviewed medical journals and scientific conferences.

Trial registration number
NL9635. EUCTR2021-004021-71-NL.

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Agosto 2022

Long-term outcomes following antenatal exposure to low-dose aspirin: study protocol for the 4-year follow-up of the APRIL randomised controlled trial

Introduction
The use of low-dose aspirin by pregnant women to prevent preterm pre-eclampsia is gradually increasing. The administration of aspirin during pregnancy improves perinatal outcome, which could translate into improved child outcome in the long term. However, antenatal exposure to aspirin could have adverse effects on child development that may manifest later in life. The aim of this follow-up study is to assess the long-term effects of antenatal exposure to low-dose aspirin compared with placebo on survival, (neuro)development, behaviour and general health at 4 years corrected age.

Methods and analysis
This is a follow-up study of the Dutch double-blind randomised controlled APRIL trial which assessed the effectiveness of treatment with aspirin (80 mg daily) compared with placebo for the prevention of preterm birth in women with a previous spontaneous preterm birth. Treatment was initiated before 16 weeks of gestation and continued until 36 weeks or birth. We aim to follow-up all 379 children born to women who participated in the APRIL trial and survived the neonatal period, at the corrected age of 4 years. The main outcomes are (neuro)development as assessed by the Ages and Stages Questionnaire, and behaviour as assessed by the Strength and Difficulties Questionnaire. Additional outcomes include mortality, growth and general health from birth up to 4 years, and a composite outcome including mortality, abnormal (neuro)development and problem behaviour. Analyses will be performed by intention-to-treat using a superiority design.

Ethics and dissemination
Institutional Review Board approval was obtained from the Medical Research Ethics Committee from Amsterdam Medical Center (no. W20 289#20.325). The results will be published in a peer-reviewed journal and presented at conferences.

Trial registration number
The APRIL trial (NTR5675, NL5553; EudraCT number 2015-003220-31) and the APRIL follow-up study (NL8950) are registered in the Dutch trial register. The study is funded by the Amsterdam Reproduction & Development research institute.

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Agosto 2022

Severe COVID-19 outcomes among patients with autoimmune rheumatic diseases or transplantation: a population-based matched cohort study

Objectives
To assess the risk of severe COVID-19 outcomes in patients with autoimmune rheumatic diseases (ARDs) and transplant recipients compared with matched general population comparators.

Design
Population-based matched cohort study using administrative health data sets.

Setting
British Columbia, Canada.

Participants
All adults with test-positive SARS-CoV-2 infections. SARS-CoV-2-positive patients with ARDs and those with transplantation were matched to SARS-CoV-2-positive general population comparators on age (±5 years), sex, month/year of initial positive SARS-CoV-2 test and health authority.

Outcome measures
COVID-19-related hospitalisations, intensive care unit (ICU) admissions, invasive ventilation and COVID-19-specific mortality. We performed multivariable conditional logistic regression models adjusting for socioeconomic status, Charlson Comorbidity Index, hypertension, rural address and number of previous COVID-19 PCR tests.

Results
Among 6279 patients with ARDs and 222 transplant recipients, all SARS-CoV-2 test positive, risk of hospitalisation was significantly increased among patients with ARDs (overall ARDs (adjusted OR (aOR) 1.30; 95% CI 1.19 to 1.43)); highest within ARDs: adult systemic vasculitides (aOR 2.18; 95% CI 1.17 to 4.05) and transplantation (aOR 10.56; 95% CI 6.88 to 16.22). Odds of ICU admission were significantly increased among patients with ARDs (overall ARDs (aOR 1.30; 95% CI 1.11 to 1.51)); highest within ARDs: ankylosing spondylitis (aOR 2.03; 95% CI 1.18 to 3.50) and transplantation (aOR 8.13; 95% CI 4.76 to 13.91). Odds of invasive ventilation were significantly increased among patients with ARDs (overall ARDs (aOR 1.60; 95% CI 1.27 to 2.01)); highest within ARDs: ankylosing spondylitis (aOR 2.63; 95% CI 1.14 to 6.06) and transplantation (aOR 8.64; 95% CI 3.81 to 19.61). Risk of COVID-19-specific mortality was increased among patients with ARDs (overall ARDs (aOR 1.24; 95% CI 1.05 to 1.47)); highest within ARDs: ankylosing spondylitis (aOR 2.15; 95% CI 1.02 to 4.55) and transplantation (aOR 5.48; 95% CI 2.82 to 10.63).

Conclusions
The risk of severe COVID-19 outcomes is increased in certain patient groups with ARDs or transplantation, although the magnitude differs across individual diseases. Strategies to mitigate risk, such as booster vaccination, prompt diagnosis and early intervention with available therapies, should be prioritised in these groups according to risk.

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Agosto 2022

Long-term effectiveness of rehabilitation services delivery for Wenchuan earthquake survivors with impairments over a 4-year period: a prospective cohort study

Objective
To examine long-term effectiveness of rehabilitation services on physical function, pain severity and post-traumatic stress disorder (PTSD) in earthquake survivors over a 4-year period.

Design
Prospective cohort study with early and late intervention and geographical control group.

Setting
Three counties of Sichuan Province, China.

Participants
591 survivors of the 2008 Wenchuan earthquake were followed-up over a 4-year period ranging from 2008 to 2012.

Interventions
In Mianzhu county, a comprehensive hospital-based and community-based rehabilitation programme was implemented in September 2008; in Anxian county, the same programme was implemented 1 year later; in Shifang county, the programme was not implemented and survivors from this county served as a control group.

Outcomes
Physical function was measured using Modified Barthel Index (MBI), pain severity with Visual Analogue Scale and PTSD with the PTSD Checklist-Civilian Version. All outcomes were assessed at three time points (baseline from 2008 to 2009, 2010 and 2012) and analysed with mixed effects regression.

Results
400 patients completed all assessments. In all groups, physical function and pain severity improved over time. MBI improvement per month as compared with control was greater in the late rehabilitation (b=1.69, 95% CI 1.20 to 2.19) than the early rehabilitation group (b=0.96, 95% CI 0.68 to 1.24). This rehabilitation effect was however marginally decreasing over time. Superior improvement as compared with control with regard to pain was only found in the early rehabilitation group (b=–0.05, 95% CI –0.09 to –0.02). PTSD symptoms decreased over time, but the observed differences could not be specifically linked to the rehabilitation intervention.

Conclusion
Physical rehabilitation of earthquake survivors appears to be effective in improving physical function and, if delivered early, pain. Effects on mental health are less clear and need further examination using more consistent and frequent assessments of relevant outcomes and determinants.

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Agosto 2022

Healthcare workers compliance with COVID-19 preventive measures, and associated factors, in Ethiopia: A systematic review and meta-analysis

Objective
Compliance with COVID-19 prevention measures limits infection occurrence and spread in healthcare settings. According to research conducted in Ethiopia, compliance with COVID-19 preventative strategies is inconsistent among healthcare providers. This systematic review and meta-analysis aimed to estimate the national pooled proportion of healthcare workers (HCWs) who adhere to COVID-19 preventive measures and associated factors with good compliance.

Design
A systematic review and meta-analysis of all identified studies with cross-sectional study design.

Data sources
A comprehensive search was conducted in PubMed/MEDLINE, POPLINE, HINARI, Science Direct, Cochrane Library databases and Google Scholar search engines from January 2020 to September 2021.

Data extraction and synthesis
This review included all observational studies conducted in Ethiopia that reported the proportion of compliance with COVID-19 preventive measures and associated factors among HCWs. Two independent authors assessed the methodological quality of studies using Joanna Briggs Institute’s meta-analysis of statistical assessment and review instrument. The effect estimates for pooled proportion and pooled OR (POR) were determined.

Results
From retrieved 611 original studies, 21 studies were included in the meta-analysis with a total of n=7933 HCWs. The pooled proportion of good compliance with COVID-19 preventive measures among HCWs was 49.7% (95% CI: 42.3% to 57.1%). Being male (POR=2.21, 95% CI: 1.52 to 3.21), service years ( >3 years) (POR=2.65, 95% CI: 1.94 to 3.64), training (POR=2.30, 95% CI: 1.78 to 2.98), positive attitude (POR=3.14, 95% CI: 1.66 to 5.94) and good knowledge (POR=2.36, 95% CI: 1.92 to 2.89) were factors significantly associated with good compliance towards COVID-19 preventive measures.

Conclusion
Our study indicated that approximately one in every two HCWs had good compliance with COVID-19 preventive measures. There must be more emphasis on providing further training sessions for the HCWs to improve their compliance with COVID-19 preventative measures.

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Agosto 2022

Exploring COVID-19 circuit breaker (CB) restrictions at a migrant worker dormitory in Singapore: a case study and nested mixed-method analysis of stress management and mental health

Introduction
Measures to mitigate the COVID-19 outbreak in the migrant worker dormitories in Singapore included lockdown and isolation of residents for prolonged periods. In this paper, we explore efforts to ease tensions and support mental health under these conditions.

Methods
Case study of dormitory residents under lockdown from April to August 2020 comprises a nested mixed-method approach using an online questionnaire (n=175) and semistructured interviews (n=23) of migrant workers sampled from the survey (August to September 2020). Logistic regression models were used to analyse survey data. Semistructured interviews were analysed using applied thematic analysis.

Results
Survey and interview data showed that mental health was largely protected despite initial rising tensions over restrictions during lockdown. Sources of tension negatively affecting low stress responses included job related worries, OR=0.07 (95% CI 0.03 to 0.18, p

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Agosto 2022

Prognostic associations of ECG tracings in hospitalised patients with COVID-19: a systematic review and meta-analysis protocol

Introduction
COVID-19 is a global pandemic caused by the SARS-CoV-2 virus. Although most COVID-19 cases are asymptomatic or mild, a significant number of patients experienced adverse outcomes. In addition, studies have shown that cardiac abnormalities are associated with increased mortality in hospitalised patients with COVID-19. This finding sets a precedent for the potential use of ECG tracing as an indicator of patient mortality and morbidity. This study aims to determine associations between the 12-lead ECG findings and various clinical outcomes of hospitalised patients with COVID-19, measured as incidence of endotracheal intubation, intensive care unit (ICU) admission and mortality rate.

Methods and analysis
An electronic literature search will identify all potentially relevant articles using specific databases and websites. The search will be limited to studies published from December 2019 to May 2021. In addition, studies will include hospitalised patients with COVID-19 with normal and abnormal 12-lead ECG findings assessed for clinical outcomes, including the incidence of endotracheal intubation, ICU admission and mortality rate. The risk of bias in individual studies will be evaluated using the Quality in Prognostic Studies tool or the Cochrane risk of bias tool. A meta-analysis will be conducted if at least two studies indicate a prognostic factor’s effect. Moreover, subgroup and sensitivity analyses will be performed accordingly to address heterogeneity. Reporting the review results will comply with the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. The quality of evidence generated will be assessed using the Grades of Recommendation, Assessment, Development and Evaluation system.

Ethics and dissemination
This study has been exempted from ethics review. There will be no patient or public involvement in this study. Furthermore, the findings will be disseminated via conferences, seminars, symposia and congresses on top of peer-reviewed journals.

PROSPERO registration number
CRD42021257155.

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Agosto 2022

Estimating the health workforce requirements and costing to reach 70% COVID-19 vaccination coverage by mid-2022: a modelling study and global estimates

Objectives
The implementation of COVID-19 vaccination globally poses unprecedented stress to health systems particularly for countries with persisting health workforce shortages prior the pandemic. The present paper estimates the workforce requirement to reach 70% COVID-19 vaccination coverage in all countries by mid-2022 using service target–based estimation.

Methods
Health workforce data from National Health Workforce Accounts and vaccination coverage reported to WHO as of January 2022 were used. Workload parameters were used to estimate the number of health workers needed with a service target–based approach, the gap and the scale-up required partially accounting for countries’ challenges, as well as the associated costs in human resources.

Results
As of 1 January 2022, only 34 countries achieved 70% COVID-19 vaccination coverage and 61 countries covered less than a quarter of their population. This analysis showed that 1 831 000 health workers working full time would be needed to reach a global coverage of 70% COVID-19 vaccination by mid-2022. To avoid severe disruptions to health system, 744 000 additional health workers should be added to domestic resources mostly (77%) in low-income countries. In a sensitivity analysis, allowing for vaccination over 12 months instead of 6 months would decrease the scale-up to 476 000 health workers. The costing for the employment of these 744 000 additional health workers is estimated to be US$2.5 billion. In addition to such a massive scale-up, it is estimated that 29 countries would have needed to redeploy more than 20% of their domestic workforce, placing them at serious risk of not achieving the mid-year target.

Conclusion
Reaching 70% global coverage with COVID-19 vaccination by mid-2022 requires extraordinary efforts not before witnessed in the history of immunisation programmes. COVID-19 vaccination programmes should receive rapid and sustainable investment in health workforce.

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Agosto 2022

Ku-gaa-gii pimitizi-win, the COVID-19 cohort study of people experiencing homelessness in Toronto, Canada: a study protocol

Introduction
Initial reports suggest people experiencing homelessness (PEH) are at high risk for SARS-CoV-2 infection and associated morbidity and mortality. However, there have been few longitudinal evaluations of the spread and impact of COVID-19 among PEH. This study will estimate the prevalence and incidence of COVID-19 infections in a cohort of PEH followed prospectively in Toronto, Canada. It will also examine associations between individual-level and shelter-level characteristics with COVID-19 infection, adverse health outcomes related to infection and vaccination. Finally, the data will be used to develop and parameterise a mathematical model to characterise SARS-CoV-2 transmission dynamics, and the transmission impact of interventions serving PEH.

Design, methods and analysis
Ku-gaa-gii pimitizi-win will follow a random sample of PEH from across Toronto (Canada) for 12 months. 736 participants were enrolled between June and September 2021, and will be followed up at 3-month intervals. At each interval, specimens (saliva, capillary blood) will be collected to determine active SARS-CoV-2 infection and serologic evidence of past infection and/or vaccination, and a detailed survey will gather self-reported information, including a detailed housing history. To examine the association between individual-level and shelter-level characteristics on COVID-19-related infection, adverse outcomes, and vaccination, shelter and healthcare administrative data will be linked to participant study data. Healthcare administrative data will also be used to examine long-term (up to 5 years) COVID-19-related outcomes among participants.

Ethics and dissemination
Ethical approval was obtained from the Unity Health Toronto and University of Toronto Health Sciences Research Ethics Boards (# 20-272). Ku-gaa-gii pimitizi-win was designed in collaboration with community and service provider partners and people having lived experience of homelessness. Findings will be reported to groups supporting Ku-gaa-gii pimitizi-win, Indigenous and other community partners and service providers, funding bodies, public health agencies and all levels of government to inform policy and public health programs.

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Agosto 2022

Global impact of COVID-19 on surgeons and team members (GlobalCOST): a cross-sectional study

Objectives
To investigate the impact of COVID-19 on the well-being of surgeons and allied health professionals as well as the support provided by their institutions.

Design
This cross-sectional study involved distributing an online survey through medical organisations, social media platforms and collaborators.

Setting
It included all staff based in an operating theatre environment around the world.

Participants
1590 complete responses were received from 54 countries between 15 July and 15 December 2020. The average age of participants was 30–40 years old, 64.9% were men and 32.5% of a white ethnic background. 79.5% were surgeons with the remainder being nurses, assistants, anaesthetists, operating department practitioners or classified other.

Main outcome measures
Participants that had experienced any physical illness, changes in mental health, salary or time with family since the start of the pandemic as well as support available based on published recommendations.

Results
32.0% reported becoming physically ill. This was more likely in those with reduced access to personal protective equipment (OR 4.62; CI 2.82 to 7.56; p

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Agosto 2022

Clinical practice guidelines and expert consensus statements on rehabilitation for patients with COVID-19: protocol for a systematic review

Introduction
COVID-19 is a highly infectious disease, characterised by respiratory, physical and psychological dysfunctions. Rehabilitation could effectively alleviate the symptoms and promote recovery of the physical and mental health of patients with COVID-19. Recently, rehabilitation medical institutions have issued clinical practice guidelines (CPGs) and expert consensus statements involving recommendations for rehabilitation assessments and rehabilitation therapies for COVID-19. This systematic review aims to assess the methodological quality and reporting quality of the guidance documents, evaluate the heterogeneity of the recommendations and summarise the recommendations with respect to rehabilitation assessments and rehabilitation therapies for COVID-19 to provide a quick reference for front-line clinicians, therapists and patients as well as reasonable suggestions for future guidelines.

Methods and analysis
The electronic databases including PubMed, Embase, Chinese Biomedical Literature Database (CBM), Chinese Science and Technology Periodical Database (VIP), Wanfang Database and China National Knowledge Infrastructure (CNKI) and websites of governments or organisations (eg, National Guideline Clearinghouse, Guidelines International Network, National Institute for Health and Clinical Excellence, Scottish Intercollegiate Guidelines Network and WHO) will be searched for eligible CPGs and expert consensus statements from inception to August 2022. CPGs and expert consensus statements published in Chinese or English and presenting recommendations for modern functional rehabilitation techniques and/or traditional Chinese medicine rehabilitation techniques for COVID-19 will be included. Reviews, interpretations, old versions of CPGs and expert consensus statements and those for the management of other diseases during the pandemic will be excluded. Two reviewers will independently review each article, extract data, appraise the methodological quality following the Appraisal of Guidelines for Research & Evaluation II tool and assess the reporting quality with the Reporting Items for Practice Guidelines in Healthcare statement. The Measurement Scale of Rate of Agreement will be used to evaluate the heterogeneity of the recommendations in different CPGs and expert consensus statements. Agreement between reviewers will be calculated using the intraclass correlation coefficient. We will also summarise the recommendations for rehabilitation in patients with COVID-19. The results will be narratively described and presented as tables or figures.

Ethics and dissemination
Ethics approval is not needed for this systematic review because information from published documents will be used. The findings will be submitted for publication in a peer-reviewed journal and reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

PROSPERO registration number
CRD42020190761.

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Agosto 2022

COVID-19 pandemic and vitamin D: rising trends in status and in daily amounts of vitamin D provided by supplements

Objectives
Since the onset of the COVID-19 pandemic in 2020, there have been plausible suggestions about the need to augment vitamin D intake by supplementation in order to prevent SARS-CoV2 infection and reduce mortality. Some groups have advocated supplementation for all adults, but governmental agencies have advocated targeted supplementation. We sought to explore the effect of the COVID-19 pandemic on both vitamin D status and on the dose of new-to-market vitamin D supplements.

Setting
University hospital, Dublin, Ireland.

Participants
Laboratory-based samples of circulating 25-hydroxyvitamin D (25OHD) (n=100 505).

Primary and secondary outcome measures
Primary outcomes: comparing yearly average 25OHD prior to the pandemic (April 2019 to March 2020) with during the pandemic (April 2020 to March 2021) and comparing the dose of new-to-market vitamin D supplements between 2017 and 2021 (n=2689). Secondary outcome: comparing prevalence of vitamin D deficiency and vitamin D excess during the two time periods.

Results
The average yearly serum 25OHD measurement increased by 2.8 nmol/L (61.4, 95% CI 61.5 to 61.7 vs 58.6, 95% CI 58.4 to 58.9, p

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Agosto 2022

Long-term and serious harms of medical cannabis and cannabinoids for chronic pain: a systematic review of non-randomised studies

Objective
To establish the prevalence of long-term and serious harms of medical cannabis for chronic pain.

Design
Systematic review and meta-analysis.

Data sources
MEDLINE, EMBASE, PsycINFO and CENTRAL from inception to 1 April 2020.

Study selection
Non-randomised studies reporting on harms of medical cannabis or cannabinoids in adults or children living with chronic pain with ≥4 weeks of follow-up.

Data extraction and synthesis
A parallel guideline panel provided input on the design and interpretation of the systematic review, including selection of adverse events for consideration. Two reviewers, working independently and in duplicate, screened the search results, extracted data and assessed risk of bias. We used random-effects models for all meta-analyses and the Grades of Recommendations, Assessment, Development and Evaluation approach to evaluate the certainty of evidence.

Results
We identified 39 eligible studies that enrolled 12 143 adult patients with chronic pain. Very low certainty evidence suggests that adverse events are common (prevalence: 26.0%; 95% CI 13.2% to 41.2%) among users of medical cannabis for chronic pain, particularly any psychiatric adverse events (prevalence: 13.5%; 95% CI 2.6% to 30.6%). Very low certainty evidence, however, indicates serious adverse events, adverse events leading to discontinuation, cognitive adverse events, accidents and injuries, and dependence and withdrawal syndrome are less common and each typically occur in fewer than 1 in 20 patients. We compared studies with

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Agosto 2022

Development and validation of an early warning score to identify COVID-19 in the emergency department based on routine laboratory tests: a multicentre case-control study

Objectives
Identifying patients with a possible SARS-CoV-2 infection in the emergency department (ED) is challenging. Symptoms differ, incidence rates vary and test capacity may be limited. As PCR-testing all ED patients is neither feasible nor effective in most centres, a rapid, objective, low-cost early warning score to triage ED patients for a possible infection is developed.

Design
Case–control study.

Setting
Secondary and tertiary hospitals in the Netherlands.

Participants
The study included patients presenting to the ED with venous blood sampling from July 2019 to July 2020 (n=10 417, 279 SARS-CoV-2-positive). The temporal validation cohort covered the period from July 2020 to October 2021 (n=14 080, 1093 SARS-CoV-2-positive). The external validation cohort consisted of patients presenting to the ED of three hospitals in the Netherlands (n=12 061, 652 SARS-CoV-2-positive).

Primary outcome measures
The primary outcome was one or more positive SARS-CoV-2 PCR test results within 1 day prior to or 1 week after ED presentation.

Results
The resulting ‘CoLab-score’ consists of 10 routine laboratory measurements and age. The score showed good discriminative ability (AUC: 0.930, 95% CI 0.909 to 0.945). The lowest CoLab-score had high sensitivity for COVID-19 (0.984, 95% CI 0.970 to 0.991; specificity: 0.411, 95% CI 0.285 to 0.520). Conversely, the highest score had high specificity (0.978, 95% CI 0.973 to 0.983; sensitivity: 0.608, 95% CI 0.522 to 0.685). The results were confirmed in temporal and external validation.

Conclusions
The CoLab-score is based on routine laboratory measurements and is available within 1 hour after presentation. Depending on the prevalence, COVID-19 may be safely ruled out in over one-third of ED presentations. Highly suspect cases can be identified regardless of presenting symptoms. The CoLab-score is continuous, in contrast to the binary outcome of lateral flow testing, and can guide PCR testing and triage ED patients.

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Agosto 2022

Effectiveness of mRNA COVID-19 vaccines against Omicron and Delta variants in a matched test-negative case-control study among US veterans

Objective
To estimate the effectiveness of messenger RNA (mRNA) booster doses during the period of Delta and Omicron variant dominance.

Design
We conducted a matched test-negative case–control study to estimate the vaccine effectiveness (VE) of three and two doses of mRNA vaccines against infection (regardless of symptoms) and against COVID-19-related hospitalisation and death.

Setting
Veterans Health Administration.

Participants
We used electronic health record data from 114 640 veterans who had a SARS-CoV-2 test during November 2021–January 2022. Patients were largely 65 years or older (52%), male (88%) and non-Hispanic white (59%).

Main outcome measures
First positive result for a SARS-CoV-2 PCR or antigen test.

Results
Against infection, booster doses had higher estimated VE (64%, 95% CI 63 to 65) than two-dose vaccination (12%, 95% CI 10 to 15) during the Omicron period. For the Delta period, the VE against infection was 90% (95% CI 88 to 92) among boosted vaccinees, higher than the VE among two-dose vaccinees (54%, 95% CI 50 to 57). Against hospitalisation, booster dose VE was 89% (95% CI 88 to 91) during Omicron and 94% (95% CI 90 to 96) during Delta; two-dose VE was 63% (95% CI 58 to 67) during Omicron and 75% (95% CI 69 to 80) during Delta. Against death, the VE with a booster dose was 94% (95% CI 90 to 96) during Omicron and 96% (95% CI 87 to 99) during Delta.

Conclusions
Among an older, mostly male, population with comorbidities, we found that an mRNA vaccine booster was highly effective against infection, hospitalisation and death. Although the effectiveness of booster vaccination against infection was moderately higher against Delta than against the Omicron SARS-CoV-2 variant, effectiveness against severe disease and death was similarly high against both variants.

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Agosto 2022