Comparative effectiveness of contact tracing interventions in the context of the COVID-19 pandemic: a systematic review

Contact tracing is a non-pharmaceutical intervention (NPI) widely used in the control of the COVID-19 pandemic. Its effectiveness may depend on a number of factors including the proportion of contacts traced, delays in tracing, the mode of contact tracing (e.g. forward, backward or bidirectional contact training), the types of contacts who are traced (e.g. contacts of index cases or contacts of contacts of index cases), or the setting where contacts are traced (e.g. the household or the workplace). We performed a systematic review of the evidence regarding the comparative effectiveness of contact tracing interventions. 78 studies were included in the review, 12 observational (ten ecological studies, one retrospective cohort study and one pre-post study with two patient cohorts) and 66 mathematical modelling studies. Based on the results from six of the 12 observational studies, contact tracing can be effective at controlling COVID-19. Two high quality ecological studies showed the incremental effectiveness of adding digital contact tracing to manual contact tracing. One ecological study of intermediate quality showed that increases in contact tracing were associated with a drop in COVID-19 mortality, and a pre-post study of acceptable quality showed that prompt contact tracing of contacts of COVID-19 case clusters / symptomatic individuals led to a reduction in the reproduction number R. Within the seven observational studies exploring the effectiveness of contact tracing in the context of the implementation of other non-pharmaceutical interventions, contact tracing was found to have an effect on COVID-19 epidemic control in two studies and not in the remaining five studies. However, a limitation in many of these studies is the lack of description of the extent of implementation of contact tracing interventions. Based on the results from the mathematical modelling studies, we identified the following highly effective policies: (1) manual contact tracing with high tracing coverage and either medium-term immunity, highly efficacious isolation/quarantine and/ or physical distancing (2) hybrid manual and digital contact tracing with high app adoption with highly effective isolation/ quarantine and social distancing, (3) secondary contact tracing, (4) eliminating contact tracing delays, (5) bidirectional contact tracing, (6) contact tracing with high coverage in reopening educational institutions. We also highlighted the role of social distancing to enhance the effectiveness of some of these interventions in the context of 2020 lockdown reopening. While limited, the evidence from observational studies shows a role for manual and digital contact tracing in controlling the COVID-19 epidemic. More empirical studies accounting for the extent of contact tracing implementation are required.Peer Reviewe

Seroprevalence and risk factors of COVID-19 in healthcare workers from 11 African countries: a scoping review and appraisal of existing evidence.

A better understanding of serological data and risk factors for coronavirus disease 2019 (COVID-19) infection in healthcare workers (HCWs) is especially important in African countries where human resources and health services are more constrained. We reviewed and appraised the evidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence and its risk factors in HCWs in Africa to inform response and preparedness strategies during the SARS-CoV-2 pandemic. We followed the Preferred Reporting Items for systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines in this scoping review. Databases including PubMed, Embase and preprint servers were searched accordingly from the start of the COVID-19 pandemic to 19 April 2021. Our search yielded 12 peer-reviewed and four pre-print articles comprising data on 9223 HCWs from 11 countries in Africa. Seroprevalence varied widely and ranged from 0% to 45.1%. Seropositivity was associated with older age, lower education, working as a nurse/non-clinical HCW or in gynaecology, emergency, outpatient or surgery departments. Asymptomatic rates were high and half of the studies recommended routine testing of HCWs. This scoping review found a varying but often high SARS-CoV-2 seroprevalence in HCWs in 11 African countries and identified certain risk factors. COVID-19 public health strategies for policy and planning should consider these risk factors and the potential for high seroprevalence among HCWs when prioritizing infection prevention and control measures and vaccine deployment

De-escalation strategies for non-pharmaceutical interventions following infectious disease outbreaks: a rapid review and a proposed dynamic de-escalation framework

BACKGROUND: The severity of COVID-19, as well as the speed and scale of its spread, has posed a global challenge. Countries around the world have implemented stringent non-pharmaceutical interventions (NPI) to control transmission and prevent health systems from being overwhelmed. These NPI have had profound negative social and economic impacts. With the timeline to worldwide vaccine roll-out being uncertain, governments need to consider to what extent they need to implement and how to de-escalate these NPI. This rapid review collates de-escalation criteria reported in the literature to provide a guide to criteria that could be used as part of de-escalation strategies globally. METHODS: We reviewed literature published since 2000 relating to pandemics and infectious disease outbreaks. The searches included Embase.com (includes Embase and Medline), LitCovid, grey literature searching, reference harvesting and citation tracking. Over 1,700 documents were reviewed, with 39 documents reporting de-escalation criteria included in the final analysis. Concepts retrieved through a thematic analysis of the included documents were interlinked to build a conceptual dynamic de-escalation framework. RESULTS: We identified 52 de-escalation criteria, the most common of which were clustered under surveillance (cited by 43 documents, 10 criteria e.g. ability to actively monitor confirmed cases and contact tracing), health system capacity (cited by 30 documents, 11 criteria, e.g. ability to treat all patients within normal capacity) and epidemiology (cited by 28 documents, 7 criteria, e.g. number or changes in case numbers). De-escalation is a gradual and bi-directional process, and resurgence of infections or emergence of variants of concerns can lead to partial or full re-escalation(s) of response and control measures in place. Hence, it is crucial to rely on a robust public health surveillance system. CONCLUSIONS: This rapid review focusing on de-escalation within the context of COVID-19 provides a conceptual framework and a guide to criteria that countries can use to formulate de-escalation plans

Mixed methods study evaluating the implementation of the WHO hand hygiene strategy focusing on alcohol based handrub and training among health care workers in Faranah, Guinea

Introduction The most frequent adverse health events in healthcare worldwide are healthcare-associated infection. Despite ongoing implementation of the WHO multimodal Hand Hygiene (HH) Improvement Strategy, healthcare-associated infection rate continues to be twofold higher in low- than in high-income countries. This study focused on continued evaluation of HH compliance and knowledge. The mixed method approach, with inclusion of patients and care-givers, provided insight into challenges and facilitators of the WHO HH Improvement Strategy, and highlighted improvement points. Methods An uncontrolled, before-and–after intervention, mixed methods study in Faranah Regional Hospital was conducted from December 2017 to August 2019. The intervention implemented the WHO HH Strategy including HH training for healthcare workers (HCWs), and the relaunch of the local production of alcohol-based handrub (ABHR). A baseline assessment of HH knowledge, perception and compliance of HCWs was done prior to the intervention and compared to two follow-up assessments. The second follow-up assessment was complemented by a qualitative component. Results Overall compliance six months post-intervention was 45.1% and significantly higher than baseline but significantly lower than in first follow-up. Knowledge showed similar patterns of improvement and waning. The perception survey demonstrated high appreciation of the intervention, such as local production of ABHR. HCW’s were concerned about overconsuming of ABHR, however simultaneous quantitative measurements showed that consumption in fact was 36% of the estimated amount needed for sufficient HH compliance. Potential fields for improvement identified by HCWs to enhance sustainability were permanent ABHR availability, having a dedicated person with ownership over continuous simulation HH trainings including simulations to improve technique. Conclusion The study shows that the WHO multimodal HH strategy has a positive effect on HCW compliance and knowledge. Improvement points identified by local staff like sensitization on appropriate ABHR amount per HH action should be considered for sustainable HH improvement.Peer Reviewe

Effectiveness and sustainability of the WHO multimodal hand hygiene improvement strategy in the University Hospital Bouaké, Republic of Côte d'Ivoire in the context of the COVID-19 pandemic

Introduction: The most frequent adverse events in healthcare are healthcare-associated infections, whose burden is highest in resource-limited settings. In addition, low resource settings often lack Hand Hygiene (HH) knowledge and reliable supply to disinfectant, a necessity emphasized by the past West African Ebola Epidemic and the ongoing COVID-19 pandemic. PASQUALE aims to increase patient safety by introducing the WHO multimodal HH strategy in the University Hospital Bouaké, Côte d’Ivoire. Methods: Assessment of HH knowledge, perception and compliance was performed 12 months before, right after the intervention and at a ten months interval using questionnaires for knowledge and perception and direct observation for compliance. The intervention consisted of a HH training and the introduction of local production of alcohol-based hand-rub. In the absence of a control group, the effectiveness of the intervention was assessed by a before-and-after study. Results: Baseline knowledge score was 14/25, increased significantly to 17/25 (p < 0.001) upon first and decreased to 13/25 in second follow-up. Compliance showed a significant increase from 12.7% to 36.8% (p < 0.001) in first and remained at 36.4% in second follow-up. Alcohol-based hand-rub production and consumption almost doubled after first confirmed COVID-19 case in Côte d’Ivoire. Conclusion: The WHO HH improvement strategy is an effective and pandemic-adaptable method to increase long-term HH compliance. This study emphasizes that the implementation of the strategy to build a robust system is of utmost importance.Peer Reviewe

Plasmacytoid Dendritic Cell Infection and Sensing Capacity during Pathogenic and Nonpathogenic Simian Immunodeficiency Virus Infection.

International audienceHuman immunodeficiency virus (HIV) in humans and simian immunodeficiency virus (SIV) in macaques (MAC) lead to chronic inflammation and AIDS. Natural hosts, such as African green monkeys (AGM) and sooty mangabeys (SM), are protected against SIV-induced chronic inflammation and AIDS. Here, we report that AGM plasmacytoid dendritic cells (pDC) express extremely low levels of CD4, unlike MAC and human pDC. Despite this, AGM pDC efficiently sensed SIVagm, but not heterologous HIV/SIV isolates, indicating a virus-host adaptation. Moreover, both AGM and SM pDC were found to be, in contrast to MAC pDC, predominantly negative for CCR5. Despite such limited CD4 and CCR5 expression, lymphoid tissue pDC were infected to a degree similar to that seen with CD4(+) T cells in both MAC and AGM. Altogether, our finding of efficient pDC infection by SIV in vivo identifies pDC as a potential viral reservoir in lymphoid tissues. We discovered low expression of CD4 on AGM pDC, which did not preclude efficient sensing of host-adapted viruses. Therefore, pDC infection and efficient sensing are not prerequisites for chronic inflammation. The high level of pDC infection by SIVagm suggests that if CCR5 paucity on immune cells is important for nonpathogenesis of natural hosts, it is possibly not due to its role as a coreceptor. The ability of certain key immune cell subsets to resist infection might contribute to the asymptomatic nature of simian immunodeficiency virus (SIV) infection in its natural hosts, such as African green monkeys (AGM) and sooty mangabeys (SM). This relative resistance to infection has been correlated with reduced expression of CD4 and/or CCR5. We show that plasmacytoid dendritic cells (pDC) of natural hosts display reduced CD4 and/or CCR5 expression, unlike macaque pDC. Surprisingly, this did not protect AGM pDC, as infection levels were similar to those found in MAC pDC. Furthermore, we show that AGM pDC did not consistently produce type I interferon (IFN-I) upon heterologous SIVmac/HIV type 1 (HIV-1) encounter, while they sensed autologous SIVagm isolates. Pseudotyping SIVmac/HIV-1 overcame this deficiency, suggesting that reduced uptake of heterologous viral strains underlays this lack of sensing. The distinct IFN-I responses depending on host species and HIV/SIV isolates reveal the host/virus species specificity of pDC sensing

Prevalence and risk factors for long COVID and post-COVID-19 condition in Africa: a systematic review

Summary Background An improved estimation of the clinical sequelae of SARS-CoV-2 infection is crucial in African countries, where the subject has received little attention despite more than 12 million reported cases and evidence that many more people were infected. We reviewed the evidence on prevalence, associated risk factors for long COVID, and systemic or sociocultural determinants of reporting long COVID. Methods We conducted a systematic review, searching PubMed, the Living OVerview of Evidence platform, and grey literature sources for publications from Dec 1, 2019, to Nov 23, 2022. We included articles published in English, French, Spanish, or Portuguese that reported on any study type in Africa with participants of any age who had symptoms for 4 weeks or more after an acute SARS-CoV-2 infection. We excluded secondary research, comments, and correspondence. Screening and data extraction were performed by two reviewers. Summary estimates were extracted, including sociodemographic factors, medical history, prevalence of persistent symptoms, and symptoms and associated factors. Results were analysed descriptively. The study was registered on the Open Science Framework platform. Findings Our search yielded 294 articles, of which 24 peer-reviewed manuscripts were included, reporting on 9712 patients from eight African countries. Only one study exclusively recruited children, and one other study included children as part of their study population. Studies indicated moderate to low risk of bias. Prevalence of long COVID varied widely, from 2% in Ghana to 86% in Egypt. Long COVID was positively associated with female sex, older age, non-Black ethnicity, low level of education, and the severity of acute infection and underlying comorbidity. HIV and tuberculosis were not identified as risk factors. Factors influencing reporting included absence of awareness, inadequate clinical data and diagnostics, and little access to health-care services. Interpretation In Africa, research on long COVID is scarce, particularly among children, who represent the majority of the population. However, existing studies show a substantial prevalence across settings, emphasising the importance of vaccination and other prevention strategies to avert the effects of long COVID on individual wellbeing, the increased strain on health systems, and the potential negative effects on economically vulnerable populations. At a global level, including African countries, tools for research on long COVID need to be harmonised to maximise the usefulness of the data collected. Funding NonePeer Reviewe

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies