A rapid review of measures to support people in isolation or quarantine during the Covid-19 pandemic and the effectiveness of such measures.

This rapid review aimed to identify measures available to support those in isolation or quarantine during the coronavirus disease 2019 (Covid-19) pandemic, and determine their effectiveness in improving adherence to these recommendations and or reducing transmission. The rapid review consisted of two elements, the first was a review of guidance published by national and international agencies relating to measures to support those in isolation (due to case status) or quarantine (due to close contact status) during the Covid-19 pandemic. Five categories of support measures were identified in the international guidance, they were: Psychological, addiction and safety supports, Essential supplies, Financial aid, Information provision and Enforcement. The second element was a rapid literature review of the effectiveness of measures used to support individuals in isolation or quarantine during any pandemic or epidemic setting, due to respiratory pathogens. A systematic search of published peer-reviewed articles and nonpeer-reviewed pre-prints was undertaken from 1 January 2000 to 26 January 2021. Two Australian publications met the inclusion criteria, both based on data from a survey undertaken during the 2009 H1N1 pandemic. The first reported that 55% of households were fully compliant with quarantine recommendations, and that there was increased compliance reported in households that understood what they were meant to do compared with those who reported that they did not (odds ratio [OR]: 2.27, 95% confidence interval [CI]: 1.35-3.80). The second reported that access to paid sick and or carer's leave did not predict compliance with quarantine recommendations (OR: 2.07, 95% CI: 0.82-5.23). Neither reported on reduction in transmission.

Immune response following infection with SARS-CoV-2 and other coronaviruses: A rapid review.

In this review, we systematically searched and summarized the evidence on the immune response and reinfection rate following SARS-CoV-2 infection. We also retrieved studies on SARS-CoV and MERS-CoV to assess the long-term duration of antibody responses. A protocol based on Cochrane rapid review methodology was adhered to and databases were searched from 1/1/2000 until 26/5/2020. Of 4744 citations retrieved, 102 studies met our inclusion criteria. Seventy-four studies were retrieved on SARS-CoV-2. While the rate and timing of IgM and IgG seroconversion were inconsistent across studies, most seroconverted for IgG within 2 weeks and 100% (N = 62) within 4 weeks. IgG was still detected at the end of follow-up (49-65 days) in all patients (N = 24). Neutralizing antibodies were detected in 92%-100% of patients (up to 53 days). It is not clear if reinfection with SARS-CoV-2 is possible, with studies more suggestive of intermittent detection of residual RNA. Twenty-five studies were retrieved on SARS-CoV. In general, SARS-CoV-specific IgG was maintained for 1-2 years post-infection and declined thereafter, although one study detected IgG up to 12 years post-infection. Neutralizing antibodies were detected up to 17 years in another study. Three studies on MERS-CoV reported that IgG may be detected up to 2 years. In conclusion, limited early data suggest that most patients seroconvert for SARS-CoV-2-specific IgG within 2 weeks. While the long-term duration of antibody responses is unknown, evidence from SARS-CoV studies suggest SARS-CoV-specific IgG is sustained for 1-2 years and declines thereafter.

Alternative clinical specimens for the detection of SARS-CoV-2: A rapid review.

The collection of nasopharyngeal swabs to test for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an invasive technique with implications for patients and clinicians. Alternative clinical specimens from the upper respiratory tract may offer benefits in terms of collection, comfort and infection risk. The objective of this review was to synthesise the evidence for detection of SARS-CoV-2 ribonucleic acid (RNA) using reverse transcription polymerase chain reaction (RT-PCR) tested saliva or nasal specimens compared with RT-PCR tested nasopharyngeal specimens. Searches were conducted in PubMed, Embase, Europe PMC and NHS evidence from December 2019 to 20 July 2020. Eighteen studies were identified; 12 for saliva, four for nasal and two included both specimen types. For saliva-based studies, the proportion of saliva samples testing positive relative to all positive samples in each study ranged from 82.9% to 100%; detection in nasopharyngeal specimens ranged from 76.7% to 100%; positive agreement between specimens for overall detection ranged from 65.4% to 100%. For nasal-based studies, the proportion of nasal swabs testing positive relative to all positive samples in each study ranged from 81.9% to 100%; detection in nasopharyngeal specimens ranged from 70% to 100%; positive agreement between specimens for overall detection ranged from 62.3% to 100%. The results indicate an inconsistency in the detection of SARS-CoV-2 RNA in the specimen types included, often with neither the index nor the reference of interest detecting all known cases. Depending on the test environment, these clinical specimens may offer a viable alternative to standard. However, at present the evidence is limited, of variable quality, and relatively inconsistent.

A cost-effectiveness and budget impact analysis of C-reactive protein point-of-care testing to guide antibiotic prescribing for acute respiratory tract infections in primary care settings in Ireland: a decision-analytic model.

BACKGROUND: Approximately 60% of antibiotics issued in primary care are for acute respiratory tract infections (RTIs), which are largely self-limiting and do not require antibiotics. Point-of-care testing (POCT) devices that measure C-reactive protein (CRP)-a biomarker for infection-can be used to guide prescribing decisions. OBJECTIVE: We evaluated the cost-effectiveness and budget impact of a national CRP POCT program to guide antibiotic prescribing for acute RTIs in primary care in Ireland. METHODS: We compared CRP POCT with and without enhanced communication skills training of general practitioners against usual care. A probabilistic decision tree was used to investigate cost-effectiveness from the perspective of the healthcare system. The model considered outcomes for the Irish population over a 5-year time horizon. Inputs were synthesized from published studies. Cost-effectiveness was estimated using an incremental cost per prescription avoided. RESULTS: CRP POCT with and without communication training were more costly but more effective than usual care over 5 years. CRP POCT alone was dominated, while the combined intervention had a cost per prescription avoided of €111 (95% CI: €45-243) versus usual care. The budget impact was costly over 5 years, but potential budget savings were available depending on the implementation scenario. The findings were largely robust to sensitivity analyses. CONCLUSIONS: CRP POCT reduces antibiotic prescribing, but increases healthcare costs. The most cost-effective program of CRP POCT includes enhanced communication skills training. Further research on the impact of CRP POCT beyond 5 years is warranted, as well as the potential impact on antimicrobial resistance.

Transmission of SARS-CoV-2 by children: a rapid review, 30 December 2019 to 10 August 2020.

BackgroundThe role of children in the transmission of SARS-CoV-2 during the early pandemic was unclear.AimWe aimed to review studies on the transmission of SARS-CoV-2 by children during the early pandemic.MethodsWe searched MEDLINE, Embase, the Cochrane Library, Europe PubMed Central and the preprint servers medRxiv and bioRxiv from 30 December 2019 to 10 August 2020. We assessed the quality of included studies using a series of questions adapted from related tools. We provide a narrative synthesis of the results.ResultsWe identified 28 studies from 17 countries. Ten of 19 studies on household and close contact transmission reported low rates of child-to-adult or child-to-child transmission. Six studies investigated transmission of SARS-CoV-2 in educational settings, with three studies reporting 183 cases from 14,003 close contacts who may have contracted COVID-19 from children index cases at their schools. Three mathematical modelling studies estimated that children were less likely to infect others than adults. All studies were of low to moderate quality.ConclusionsDuring the early pandemic, it appeared that children were not substantially contributing to household transmission of SARS-CoV-2. School-based studies indicated that transmission rates in this setting were low. Large-scale studies of transmission chains using data collected from contact tracing and serological studies detecting past evidence of infection would be needed to verify our findings.

Antiviral agents for infectious mononucleosis (glandular fever).

BACKGROUND: Infectious mononucleosis (IM) is a clinical syndrome, usually caused by the Epstein Barr virus (EPV), characterised by lymphadenopathy, fever and sore throat. Most cases of symptomatic IM occur in older teenagers or young adults. Usually IM is a benign self-limiting illness and requires only symptomatic treatment. However, occasionally the disease course can be complicated or prolonged and lead to decreased productivity in terms of school or work. Antiviral medications have been used to treat IM, but the use of antivirals for IM is controversial. They may be effective by preventing viral replication which helps to keep the virus inactive. However, there are no guidelines for antivirals in IM. OBJECTIVES: To assess the effects of antiviral therapy for infectious mononucleosis (IM). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, March 2016), which contains the Cochrane Acute Respiratory Infections (ARI) Group's Specialised Register, MEDLINE (1946 to 15 April 2016), Embase (1974 to 15 April 2016), CINAHL (1981 to 15 April 2016), LILACS (1982 to 15 April 2016) and Web of Science (1955 to 15 April 2016). We searched the World Health Organization (WHO) International Clinical Trials Registry Platform and ClinicalTrials.gov for completed and ongoing trials. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing antivirals versus placebo or no treatment in IM. We included trials of immunocompetent participants of any age or sex with clinical and laboratory-confirmed diagnosis of IM, who had symptoms for up to 14 days. Our primary outcomes were time to clinical recovery and adverse events and side effects of medication. Secondary outcomes included duration of abnormal clinical examination, complications, viral shedding, health-related quality of life, days missing from school or work and economic outcomes. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, assessed the included studies' risk of bias and extracted data using a customised data extraction sheet. We used the GRADE criteria to rate the quality of the evidence. We pooled heterogeneous data where possible, and presented the results narratively where we could not statistically combine data. MAIN RESULTS: We included seven RCTs with a total of 333 participants in our review. Three trials studied hospitalised patients, two trials were conducted in an outpatient setting, while the trial setting was unclear in two studies. Participants' ages ranged from two years to young adults. The type of antiviral, administration route, and treatment duration varied between the trials. The antivirals in the included studies were acyclovir, valomaciclovir and valacyclovir. Follow-up varied from 20 days to six months. The diagnosis of IM was based on clinical symptoms and laboratory parameters.The risk of bias for all included studies was either unclear or high risk of bias. The quality of evidence was graded as very low for all outcomes and so the results should be interpreted with caution. There were statistically significant improvements in the treatment group for two of the 12 outcomes. These improvements may be of limited clinical significance.There was a mean reduction in 'time to clinical recovery as assessed by physician' of five days in the treatment group but with wide confidence intervals (CIs) (95% CI -8.04 to -1.08; two studies, 87 participants). Prospective studies indicate that clinical signs and symptoms may take one month or more to resolve and that fatigue may be persistent in approximately 10% of patients at six-month follow-up, so this may not be a clinically meaningful result.Trial results for the outcome 'adverse events and side effects of medication' were reported narratively in only five studies. In some reports authors were unsure whether an adverse event was related to medication or complication of disease. These results could not be pooled due to the potential for double counting results but overall, the majority of trials reporting this outcome did not find any significant difference between treatment and control groups.There was a mean reduction in 'duration of lymphadenopathy' of nine days (95% CI -11.75 to -6.14, two studies, 61 participants) in favour of the treatment group.In terms of viral shedding, the overall effect from six studies was that viral shedding was suppressed while on antiviral treatment, but this effect was not sustained when treatment stopped.For all other outcomes there was no statistically significant difference between antiviral treatment and control groups. AUTHORS' CONCLUSIONS: The effectiveness of antiviral agents (acyclovir, valomaciclovir and valacyclovir) in acute IM is uncertain. The quality of the evidence is very low. The majority of included studies were at unclear or high risk of bias and so questions remain about the effectiveness of this intervention. Although two of the 12 outcomes have results that favour treatment over control, the quality of the evidence of these results is very low and may not be clinically meaningful. Alongside the lack of evidence of effectiveness, decision makers need to consider the potential adverse events and possible associated costs, and antiviral resistance. Further research in this area is warranted.

Prevalence of prescribing in pregnancy using the Irish primary care research network: a pilot study.

BACKGROUND: To establish the prevalence and patterns of prescribing to pregnant women in an Irish primary care setting. METHODS: We reviewed electronic healthcare records routinely collected in primary care, of pregnant women attending nine Dublin-based General Practices affiliated to the Irish Primary Care Research Network (IPCRN) for antenatal care between January 2007 and October 2013 (n = 2,361 pregnancies). RESULTS: Excluding folic acid, 46.8% (n = 1,104) of pregnant women were prescribed at least one medication. Amoxicillin (11.1%, n = 263) and co-amoxiclav (8.0%, n = 190) were the most commonly prescribed medication followed by topical clotrimazole (4.9%, n = 117), salbutamol inhalers (4.1%, n = 96) and paracetamol (4.0%, n = 95). General Medical Services (GMS) patients were more likely to receive a prescription than private patients (OR 2.81; 95%CI (2.28, 3.47)). We applied the US FDA pregnancy-risk categories as a proxy measure of prescribing appropriateness, with FDA Category D and X medications considered inappropriate. FDA Category D drugs were prescribed in 5.9% (n = 140) of pregnancies. FDA Category X drugs were prescribed in 4.9% (n = 116) of pregnancies but after exclusion of oral contraceptives, progestogens, infertility treatments Category X medications were prescribed in 0.6% (n = 13) of pregnancies. After the initial antenatal consultation the prescribing prevalence of FDA Category D medications reduced to 4.7% (n = 110) and Category X to 3.1% (n = 72). CONCLUSIONS: The overall prevalence of prescribing to pregnant women in our cohort is low compared to studies internationally, however similar levels of prescribing for FDA Category D and X were found. Following the initial antenatal consultation levels of prescribing of the FDA Category D and X medications reduced, however there is potential to further reduce their use in early pregnancy. The IPCRN database has provided valuable information on the current practice of antenatal prescribing within this pilot group of practices however it is limited by the absence of morbidity and pregnancy outcome data.

Health and use of health services of people who are homeless and at risk of homelessness who receive free primary health care in Dublin.

BACKGROUND: Homeless populations experience poorer physical and mental health, and more barriers to accessing adequate healthcare. This study investigates the health of this population, following the provision of a free to access primary care service for homeless people in Dublin (Safetynet). The health of this group will be compared to previous studies on homelessness conducted in Dublin prior to the establishment of this service (in 1997 and 2005). METHODS: Participants were recruited through Safetynet clinics. A 133-item questionnaire was administered to determine participants' physical and mental well-being, use of health services and healthcare needs. Prescription data was extracted from participants' electronic health records. RESULTS: A total of 105 participants were recruited. The majority were < 45 years of age (69%), male (75%), single (52%), Irish (74%) and had children (52%). Multimorbidity was common; with 5.3 ± 2.7 (mean ± SD) physical conditions reported per person. A large proportion of participants had at some point received a formal diagnosis of a mental health condition (70%; 73/105), including depression (50%; 52/105), addiction disorder (39%), anxiety (36%; 38/105), schizophrenia (13%; 14/105) and bipolar disorder (6%; 6/105). With regards to illicit drug use, 60% (63/105) of participants reported ever using drugs, while 33% (35/105) reported being active drug users. Based on AUDIT C criteria, 53% had an alcohol problem. Compared to previous studies, participants reported more positive ratings of health (70% vs. 57% in 1997 and 46% in 2005). The proportion of participants on one or more prescription medication was higher than in previous studies (81% vs. 32% in 1997 and 49% in 2005) and there was a decrease in attendance at outpatients departments (17% vs. 27% in 2005) and a trend towards a decrease in attendance at Accident and Emergency departments (A & E) (29% vs. 37% in 2005). CONCLUSIONS: This vulnerable population has many physical and mental health problems. Use of drugs, alcohol and smoking is common. Following the establishment of Safetynet, self-reported health was rated more positively, there was also a decrease in the use of A & E and outpatient services and an increase in prescription medicines.

Developing an international register of clinical prediction rules for use in primary care: a descriptive analysis.

PURPOSE: We describe the methodology used to create a register of clinical prediction rules relevant to primary care. We also summarize the rules included in the register according to various characteristics. METHODS: To identify relevant articles, we searched the MEDLINE database (PubMed) for the years 1980 to 2009 and supplemented the results with searches of secondary sources (books on clinical prediction rules) and personal resources (eg, experts in the field). The rules described in relevant articles were classified according to their clinical domain, the stage of development, and the clinical setting in which they were studied. RESULTS: Our search identified clinical prediction rules reported between 1965 and 2009. The largest share of rules (37.2%) were retrieved from PubMed. The number of published rules increased substantially over the study decades. We included 745 articles in the register; many contained more than 1 clinical prediction rule study (eg, both a derivation study and a validation study), resulting in 989 individual studies. In all, 434 unique rules had gone through derivation; however, only 54.8% had been validated and merely 2.8% had undergone analysis of their impact on either the process or outcome of clinical care. The rules most commonly pertained to cardiovascular disease, respiratory, and musculoskeletal conditions. They had most often been studied in the primary care or emergency department settings. CONCLUSIONS: Many clinical prediction rules have been derived, but only about half have been validated and few have been assessed for clinical impact. This lack of thorough evaluation for many rules makes it difficult to retrieve and identify those that are ready for use at the point of patient care. We plan to develop an international web-based register of clinical prediction rules and computer-based clinical decision support systems.

The former annotated human pseudogene dihydrofolate reductase-like 1 (DHFRL1) is expressed and functional.

Human dihydrofolate reductase (DHFR) was previously thought to be the only enzyme capable of the reduction of dihydrofolate to tetrahydrofolate; an essential reaction necessary to ensure a continuous supply of biologically active folate. DHFR has been studied extensively from a number of perspectives because of its role in health and disease. Although the presence of a number of intronless DHFR pseudogenes has been known since the 1980s, it was assumed that none of these were expressed or functional. We show that humans do have a second dihydrofolate reductase enzyme encoded by the former pseudogene DHFRP4, located on chromosome 3. We demonstrate that the DHFRP4, or dihydrofolate reductase-like 1 (DHFRL1), gene is expressed and shares some commonalities with DHFR. Recombinant DHFRL1 can complement a DHFR-negative phenotype in bacterial and mammalian cells but has a lower specific activity than DHFR. The K(m) for NADPH is similar for both enzymes but DHFRL1 has a higher K(m) for dihydrofolate when compared to DHFR. The need for a second reductase with lowered affinity for its substrate may fulfill a specific cellular requirement. The localization of DHFRL1 to the mitochondria, as demonstrated by confocal microscopy, indicates that mitochondrial dihydrofolate reductase activity may be optimal with a lowered affinity for dihydrofolate. We also found that DHFRL1 is capable of the same translational autoregulation as DHFR by binding to its own mRNA; with each enzyme also capable of replacing the other. The identification of DHFRL1 will have implications for previous research involving DHFR.

Diagnostic Accuracy of 18F-Prostate Specific Membrane Antigen (PSMA) PET/CT Radiotracers in Staging and Restaging of Patients With High-Risk Prostate Cancer or Biochemical Recurrence: An Overview of Reviews.

The aim of this overview was to consolidate existing evidence syntheses and provide a comprehensive overview of the evidence for 18F-prostate specific membrane antigen (PSMA) PET/CT in the staging of high-risk prostate cancer and restaging after biochemical recurrence. An overview of reviews was performed and reported in line with the preferred reporting items for overview of reviews (PRIOR) statement and synthesis without meta-analysis (SWiM) reporting guidelines. A comprehensive database and grey literature search were conducted up to July 18, 2023. Systematic reviews were assessed using the risk of bias in systematic reviews (ROBIS) tool. The certainty of the evidence was assessed using grading of recommendations, assessment, development and evaluations (GRADE). 11 systematic reviews were identified; 10 were at high or unclear risk of bias. Evidence reported on a per-patient, per-lymph node, and per-lesion basis for sensitivity, specificity and overall accuracy was identified. There was a lack of data on dose, adverse events and evidence directly comparing 18F-PSMA PET/CT to other imaging modalities. Evidence with moderate to very low certainty indicated high sensitivity, specificity and accuracy of 18F-PSMA PET/CT in patients with high-risk prostate cancer and biochemical recurrence. There was considerably lower certainty evidence and greater variability in effect estimates for outcomes for the combined intermediate/high-risk cohort. While evidence gaps remain for some outcomes, and most systematic reviews were at high or unclear risk of bias, the current evidence base is broadly supportive of 18F-PSMA PET/CT imaging in the staging and restaging of patients with high-risk prostate cancer and biochemical recurrence.

Diagnostic accuracy of 18F Prostate Specific Membrane Antigen (PSMA) PET-CT radiotracers in staging and restaging of high-risk prostate cancer patients and patients with biochemical recurrence: protocol for an overview of reviews.

Background: Correct staging and risk stratification is essential in ensuring prostate cancer patients are offered the most appropriate treatment. Interest has been growing in the use of radiotracers targeting prostate specific membrane antigen (PSMA), including the use of 18F-PSMA PET-CT, as part of the primary staging or restaging of prostate cancer. Preliminary scoping identified a number of relevant systematic reviews and meta-analyses; however, individually, these each appear to look at only part of the picture. An overview of reviews aims to systematically identify, appraise and synthesise multiple systematic reviews, related to a relevant research question or questions. We present a protocol for an overview of reviews, which aims to collate existing evidence syntheses exploring the diagnostic accuracy of 18F-PSMA in staging and restaging of prostate cancer. It also aims to highlight evidence gaps in prostate cancer staging or restaging. Methods: This protocol is reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for systematic review protocols (PRISMA-P). The search strategy will be designed in consultation with a librarian. Searches will be performed in Medline (EBSCO), Embase (Ovid), Google Scholar and the Cochrane Database for Systematic Reviews, supplemented by a targeted grey literature search, forward citation searching and searching reference lists of included reviews. No language or date restrictions will be applied to the eligibility criteria or the search strategy. Title & abstract and full text screening will be performed independently by two reviewers. Data will be extracted by one reviewer and checked in full by a second reviewer. Quality appraisal will be performed using the Risk of Bias in Systematic Reviews (ROBIS) tool independently by two reviewers, and results will be narratively synthesised. Conclusions: This overview of reviews may be of interest to healthcare professionals, academics and health policy decision-makers. Registration: OSF (September 7, 2023).

Evaluating the Association Between Low-Density Lipoprotein Cholesterol Reduction and Relative and Absolute Effects of Statin Treatment: A Systematic Review and Meta-analysis.

Importance: The association between statin-induced reduction in low-density lipoprotein cholesterol (LDL-C) levels and the absolute risk reduction of individual, rather than composite, outcomes, such as all-cause mortality, myocardial infarction, or stroke, is unclear. Objective: To assess the association between absolute reductions in LDL-C levels with treatment with statin therapy and all-cause mortality, myocardial infarction, and stroke to facilitate shared decision-making between clinicians and patients and inform clinical guidelines and policy. Data Sources: PubMed and Embase were searched to identify eligible trials from January 1987 to June 2021. Study Selection: Large randomized clinical trials that examined the effectiveness of statins in reducing total mortality and cardiovascular outcomes with a planned duration of 2 or more years and that reported absolute changes in LDL-C levels. Interventions were treatment with statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) vs placebo or usual care. Participants were men and women older than 18 years. Data Extraction and Synthesis: Three independent reviewers extracted data and/or assessed the methodological quality and certainty of the evidence using the risk of bias 2 tool and Grading of Recommendations, Assessment, Development and Evaluation. Any differences in opinion were resolved by consensus. Meta-analyses and a meta-regression were undertaken. Main Outcomes and Measures: Primary outcome: all-cause mortality. Secondary outcomes: myocardial infarction, stroke. Findings: Twenty-one trials were included in the analysis. Meta-analyses showed reductions in the absolute risk of 0.8% (95% CI, 0.4%-1.2%) for all-cause mortality, 1.3% (95% CI, 0.9%-1.7%) for myocardial infarction, and 0.4% (95% CI, 0.2%-0.6%) for stroke in those randomized to treatment with statins, with associated relative risk reductions of 9% (95% CI, 5%-14%), 29% (95% CI, 22%-34%), and 14% (95% CI, 5%-22%) respectively. A meta-regression exploring the potential mediating association of the magnitude of statin-induced LDL-C reduction with outcomes was inconclusive. Conclusions and Relevance: The results of this meta-analysis suggest that the absolute risk reductions of treatment with statins in terms of all-cause mortality, myocardial infarction, and stroke are modest compared with the relative risk reductions, and the presence of significant heterogeneity reduces the certainty of the evidence. A conclusive association between absolute reductions in LDL-C levels and individual clinical outcomes was not established, and these findings underscore the importance of discussing absolute risk reductions when making informed clinical decisions with individual patients.

The Alvarado score for predicting acute appendicitis: a systematic review.

BACKGROUND: The Alvarado score can be used to stratify patients with symptoms of suspected appendicitis; the validity of the score in certain patient groups and at different cut points is still unclear. The aim of this study was to assess the discrimination (diagnostic accuracy) and calibration performance of the Alvarado score. METHODS: A systematic search of validation studies in Medline, Embase, DARE and The Cochrane library was performed up to April 2011. We assessed the diagnostic accuracy of the score at the two cut-off points: score of 5 (1 to 4 vs. 5 to 10) and score of 7 (1 to 6 vs. 7 to 10). Calibration was analysed across low (1 to 4), intermediate (5 to 6) and high (7 to 10) risk strata. The analysis focused on three sub-groups: men, women and children. RESULTS: Forty-two studies were included in the review. In terms of diagnostic accuracy, the cut-point of 5 was good at 'ruling out' admission for appendicitis (sensitivity 99% overall, 96% men, 99% woman, 99% children). At the cut-point of 7, recommended for 'ruling in' appendicitis and progression to surgery, the score performed poorly in each subgroup (specificity overall 81%, men 57%, woman 73%, children 76%). The Alvarado score is well calibrated in men across all risk strata (low RR 1.06, 95% CI 0.87 to 1.28; intermediate 1.09, 0.86 to 1.37 and high 1.02, 0.97 to 1.08). The score over-predicts the probability of appendicitis in children in the intermediate and high risk groups and in women across all risk strata. CONCLUSIONS: The Alvarado score is a useful diagnostic 'rule out' score at a cut point of 5 for all patient groups. The score is well calibrated in men, inconsistent in children and over-predicts the probability of appendicitis in women across all strata of risk.

Predicting streptococcal pharyngitis in adults in primary care: a systematic review of the diagnostic accuracy of symptoms and signs and validation of the Centor score.

BACKGROUND: Stratifying patients with a sore throat into the probability of having an underlying bacterial or viral cause may be helpful in targeting antibiotic treatment. We sought to assess the diagnostic accuracy of signs and symptoms and validate a clinical prediction rule (CPR), the Centor score, for predicting group A ß-haemolytic streptococcal (GABHS) pharyngitis in adults (> 14 years of age) presenting with sore throat symptoms. METHODS: A systematic literature search was performed up to July 2010. Studies that assessed the diagnostic accuracy of signs and symptoms and/or validated the Centor score were included. For the analysis of the diagnostic accuracy of signs and symptoms and the Centor score, studies were combined using a bivariate random effects model, while for the calibration analysis of the Centor score, a random effects model was used. RESULTS: A total of 21 studies incorporating 4,839 patients were included in the meta-analysis on diagnostic accuracy of signs and symptoms. The results were heterogeneous and suggest that individual signs and symptoms generate only small shifts in post-test probability (range positive likelihood ratio (+LR) 1.45-2.33, -LR 0.54-0.72). As a decision rule for considering antibiotic prescribing (score ≥ 3), the Centor score has reasonable specificity (0.82, 95% CI 0.72 to 0.88) and a post-test probability of 12% to 40% based on a prior prevalence of 5% to 20%. Pooled calibration shows no significant difference between the numbers of patients predicted and observed to have GABHS pharyngitis across strata of Centor score (0-1 risk ratio (RR) 0.72, 95% CI 0.49 to 1.06; 2-3 RR 0.93, 95% CI 0.73 to 1.17; 4 RR 1.14, 95% CI 0.95 to 1.37). CONCLUSIONS: Individual signs and symptoms are not powerful enough to discriminate GABHS pharyngitis from other types of sore throat. The Centor score is a well calibrated CPR for estimating the probability of GABHS pharyngitis. The Centor score can enhance appropriate prescribing of antibiotics, but should be used with caution in low prevalence settings of GABHS pharyngitis such as primary care.

The relationship between procedural volume and patient outcomes for percutaneous coronary interventions: a systematic review and meta-analysis.

BACKGROUND: The relationship between procedural volume and outcomes for percutaneous coronary interventions (PCI) is contentious, with previous reviews suggesting an inverse volume-outcome relationship. The aim of this study was to systematically review contemporary evidence to re-examine this relationship. METHODS: A systematic review and meta-analysis was undertaken to examine the relationship between PCI procedural volume (both at hospital- and operator-levels) and outcomes in adults. The primary outcome was mortality. The secondary outcomes were complications, healthcare utilisation and process outcomes. Searches were conducted from 1 January 2008 to 28 May 2019. Certainty of the evidence was assessed using 'Grading of Recommendations, Assessment, Development and Evaluations' (GRADE). Screening, data extraction, quality appraisal and GRADE assessments were conducted independently by two reviewers. RESULTS: Of 1,154 unique records retrieved, 22 observational studies with 6,432,265 patients were included. No significant association was found between total PCI hospital volume and mortality (odds ratio [OR]: 0.84, 95% confidence interval [CI]: 0.69-1.03, I 2 = 86%). A temporal trend from significant to non-significant pooled effect estimates was observed. The pooled effect estimate for mortality was found to be significantly in favour of high-volume operators for total PCI procedures (OR: 0.77, 95% CI: 0.63-0.94, I 2 = 93%), and for high-volume hospitals for primary PCI procedures (OR: 0.77, 95% CI: 0.62-0.94, I 2 = 78%). Overall, GRADE certainty of evidence was 'very low'. There were mixed findings for secondary outcomes. CONCLUSIONS: A volume-outcome relationship may exist in certain situations, although this relationship appears to be attenuating with time, and there is 'very low' certainty of evidence. While volume might be important, it should not be the only standard used to define an acceptable PCI service and a broader evaluation of quality metrics should be considered that encompass patient experience and clinical outcomes. Systematic review registration: PROSPERO, CRD42019125288.

Presymptomatic transmission of SARS-CoV-2 infection: a secondary analysis using published data.

OBJECTIVE: To estimate the proportion of presymptomatic transmission of SARS-CoV-2 infection that can occur, and the timing of transmission relative to symptom onset. SETTING/DESIGN: Secondary analysis of international published data. DATA SOURCES: Meta-analysis of COVID-19 incubation period and a rapid review of serial interval and generation time, which are published separately. PARTICIPANTS: Data from China, the Islamic Republic of Iran, Italy, Republic of Korea, Singapore and Vietnam from December 2019 to May 2020. METHODS: Simulations were generated of incubation period and of serial interval or generation time. From these, transmission times relative to symptom onset, and the proportion of presymptomatic transmission, were estimated. OUTCOME MEASURES: Transmission time of SARS-CoV-2 relative to symptom onset and proportion of presymptomatic transmission. RESULTS: Based on 18 serial interval/generation time estimates from 15 papers, mean transmission time relative to symptom onset ranged from -2.6 (95% CI -3.0 to -2.1) days before infector symptom onset to 1.4 (95% CI 1.0 to 1.8) days after symptom onset. The proportion of presymptomatic transmission ranged from 45.9% (95% CI 42.9% to 49.0%) to 69.1% (95% CI 66.2% to 71.9%). CONCLUSIONS: There is substantial potential for presymptomatic transmission of SARS-CoV-2 across a range of different contexts. This highlights the need for rapid case detection, contact tracing and quarantine. The transmission patterns that we report reflect the combination of biological infectiousness and transmission opportunities which vary according to context.

Inferred duration of infectious period of SARS-CoV-2: rapid scoping review and analysis of available evidence for asymptomatic and symptomatic COVID-19 cases.

OBJECTIVES: Our objective was to review the literature on the inferred duration of the infectious period of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, and provide an overview of the variation depending on the methodological approach. DESIGN: Rapid scoping review. Literature review with fixed search terms, up to 1 April 2020. Central tendency and variation of the parameter estimates for infectious period in (A) asymptomatic and (B) symptomatic cases from (1) virological studies (repeated testing), (2) tracing studies and (3) modelling studies were gathered. Narrative review of viral dynamics. INFORMATION SOURCES: Search strategies developed and the following searched: PubMed, Google Scholar, MedRxiv and BioRxiv. Additionally, the Health Information Quality Authority (Ireland) viral load synthesis was used, which screened literature from PubMed, Embase, ScienceDirect, NHS evidence, Cochrane, medRxiv and bioRxiv, and HRB open databases. RESULTS: There was substantial variation in the estimates, and how infectious period was inferred. One study provided approximate median infectious period for asymptomatic cases of 6.5-9.5 days. Median presymptomatic infectious period across studies varied over <1-4 days. Estimated mean time from symptom onset to two negative RT-PCR tests was 13.4 days (95% CI 10.9 to 15.8) but was shorter when studies included children or less severe cases. Estimated mean duration from symptom onset to hospital discharge or death (potential maximal infectious period) was 18.1 days (95% CI 15.1 to 21.0); time to discharge was on average 4 days shorter than time to death. Viral dynamic data and model infectious parameters were often shorter than repeated diagnostic data. CONCLUSIONS: There are limitations of inferring infectiousness from repeated diagnosis, viral loads and viral replication data alone and also potential patient recall bias relevant to estimating exposure and symptom onset times. Despite this, available data provide a preliminary evidence base to inform models of central tendency for key parameters and variation for exploring parameter space and sensitivity analysis.

SARS-CoV-2 detection, viral load and infectivity over the course of an infection.

OBJECTIVES: To summarise the evidence on the detection pattern and viral load of SARS-CoV-2 over the course of an infection (including any asymptomatic or pre-symptomatic phase), and the duration of infectivity. METHODS: A systematic literature search was undertaken in PubMed, Europe PubMed Central and EMBASE from 30 December 2019 to 12 May 2020. RESULTS: We identified 113 studies conducted in 17 countries. The evidence from upper respiratory tract samples suggests that the viral load of SARS-CoV-2 peaks around symptom onset or a few days thereafter, and becomes undetectable about two weeks after symptom onset; however, viral loads from sputum samples may be higher, peak later and persist for longer. There is evidence of prolonged virus detection in stool samples, with unclear clinical significance. No study was found that definitively measured the duration of infectivity; however, patients may not be infectious for the entire duration of virus detection, as the presence of viral ribonucleic acid may not represent transmissible live virus. CONCLUSION: There is a relatively consistent trajectory of SARS-CoV-2 viral load over the course of COVID-19 from respiratory tract samples, however the duration of infectivity remains uncertain.

A common variant in MTHFD1L is associated with neural tube defects and mRNA splicing efficiency.

Polymorphisms in folate-related genes have emerged as important risk factors in a range of diseases including neural tube defects (NTDs), cancer, and coronary artery disease (CAD). Having previously identified a polymorphism within the cytoplasmic folate enzyme, MTHFD1, as a maternal risk factor for NTDs, we considered the more recently identified mitochondrial paralogue, MTHFD1L, as a candidate gene for NTD association. We identified a common deletion/insertion polymorphism, rs3832406, c.781-6823ATT(7-9), which influences splicing efficiency and is strongly associated with NTD risk. Three alleles of rs3832406 were detected in the Irish population with varying numbers of ATT repeats: Allele 1 consists of ATT(7), whereas Alleles 2 and 3 consist of ATT(8) and ATT(9), respectively. Allele 2 of this triallelic polymorphism showed a decreased case risk as demonstrated by case-control logistic regression (P=0.002) and by transmission disequilibrium test (TDT) (P=0.001), whereas Allele 1 showed an increased case risk. Allele 3 showed no influence on NTD risk and represents the lowest frequency allele (0.15). Additional single nucleotide polymorphism (SNP) genotyping in the same genomic region provides additional supportive evidence of an association. We demonstrate that two of the three alleles of rs3832406 are functionally different and influence the splicing efficiency of the alternate MTHFD1L mRNA transcripts.