The prevalence of adaptive immunity to COVID-19 and reinfection after recovery - a comprehensive systematic review and meta-analysis.

This study aims to estimate the prevalence and longevity of detectable SARS-CoV-2 antibodies and T and B memory cells after recovery. In addition, the prevalence of COVID-19 reinfection and the preventive efficacy of previous infection with SARS-CoV-2 were investigated. A synthesis of existing research was conducted. The Cochrane Library, the China Academic Journals Full Text Database, PubMed, and Scopus, and preprint servers were searched for studies conducted between 1 January 2020 to 1 April 2021. Included studies were assessed for methodological quality and pooled estimates of relevant outcomes were obtained in a meta-analysis using a bias adjusted synthesis method. Proportions were synthesized with the Freeman-Tukey double arcsine transformation and binary outcomes using the odds ratio (OR). Heterogeneity was assessed using the I2 and Cochran's Q statistics and publication bias was assessed using Doi plots. Fifty-four studies from 18 countries, with around 12,000,000 individuals, followed up to 8 months after recovery, were included. At 6-8 months after recovery, the prevalence of SARS-CoV-2 specific immunological memory remained high; IgG - 90.4% (95%CI 72.2-99.9, I2 = 89.0%), CD4+ - 91.7% (95%CI 78.2-97.1y), and memory B cells 80.6% (95%CI 65.0-90.2) and the pooled prevalence of reinfection was 0.2% (95%CI 0.0-0.7, I2 = 98.8). Individuals previously infected with SARS-CoV-2 had an 81% reduction in odds of a reinfection (OR 0.19, 95% CI 0.1-0.3, I2 = 90.5%). Around 90% of recovered individuals had evidence of immunological memory to SARS-CoV-2, at 6-8 months after recovery and had a low risk of reinfection.RegistrationPROSPERO: CRD42020201234.

The delivery of obesity interventions to children and adolescents with physical disabilities: a systematic review.

BACKGROUND: To examine the process and mechanisms of delivering obesity interventions to physically disabled children/adolescents. METHODS: PubMed, Medline, CINAHL Plus, Embase, Cochrane Library, Google Scholar, ClinicalTrials.gov, Science Direct were systematically and manually searched for studies conducted in physically disabled children/adolescents (0-18 years). Included interventions were physical activity, diet and obesity prevention education. Included outcomes were body mass index (BMI)/weight and obesity prevention knowledge. The Mixed Methods Appraisal Tool aided methodological quality assessments. Data were extracted and delivery models were synthesized and narratively summarized using the social ecological model. RESULTS: Seven studies of low (n = 4) and moderate (n = 3) scoring on methodological quality were eligible for inclusion. Study duration was 5 months or less (n = 5), 8 months (n = 1) and 2 years (n = 1). Interventions were delivered at home, school, hospital and rehabilitation centre through the internet, face-to-face and parents. No intervention was delivered at three or more levels of individual, interpersonal, institutional or community levels. No study reported significant outcomes on reduction in BMI/weight, or increase in obesity prevention knowledge. CONCLUSIONS: Evidence reviewed in this study shows that obesity interventions for physically disabled children/adolescents lack both in delivery and design. Gaps revealed should be considered when developing interventions for this special population.

The diagnostic accuracy of HbA1c , compared to the oral glucose tolerance test, for screening for type 2 diabetes mellitus in Africa-A systematic review and meta-analysis.

OBJECTIVE: To assess the diagnostic accuracy of glycated haemoglobin A1c (HbA1c ), compared to fasting plasma glucose (FPG) and the oral glucose tolerance test (OGTT), in screening for type 2 diabetes (T2D) in Africa. METHODS: We systematically searched databases for studies that compared the HbA1c to either the OGTT, or the FPG for T2D diagnosis were included. The QUADAS 2 tool was used for assessing the quality of included studies. We used the split component synthesis (SCS) method for the meta-analysis of diagnostic accuracy studies to pool the studies for meta-analysis of sensitivity and specificity, primarily at the HbA1c ≥48 mmol/mol (6.5%) cut-off and at other cut-offs. We assessed heterogeneity using the I2  statistic and publication bias using Doi plots. RESULTS: Eleven studies, from seven African countries, with 12,925 participants, were included. Against the OGTT, HbA1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 57.7% (95% confidence interval [CI] 43.4-70.9) and specificity of 92.3% (95% CI 83.9-96.5). Against the FPG, HbA1c ≥48 mmol/mol (6.5%) had a pooled sensitivity of 64.5% (95% CI 50.5-76.4) and specificity of 94.3% (95% CI 87.9-97.5). The highest sensitivity for HbA1c , against the OGTT, was at the 42 mmol/mol (6.0%) cut-off. CONCLUSION: In Africa, the HbA1c ≥48 mmol/mol (6.5%) cut-off may miss almost half of the individuals with T2D based on blood glucose measures.

Efficacy of chloroquine and hydroxychloroquine in treating COVID-19 infection: A meta-review of systematic reviews and an updated meta-analysis.

OBJECTIVE: To synthesize findings from systematic reviews and meta-analyses on the efficacy and safety of chloroquine (CQ) and hydroxychloroquine (HCQ) with or without Azithromycin for treating COVID-19, and to update the evidence using a meta-analysis. METHODS: A comprehensive search was carried out in electronic databases for systematic reviews, meta-analyses and experimental studies which investigated the efficacy and safety of CQ, HCQ with or without Azithromycin to treat COVID-19. Findings from the reviews were synthesised using tables and forest plots and the quality effect model was used for the updated meta-analysis. The main outcomes were mortality, the need for intensive care services, disease exacerbation, viral clearance and occurrence of adverse events. RESULTS: Thirteen reviews with 40 primary studies were included. Two meta-analyses reported a high risk of mortality, with ORs of 2.2 and 3.0, and the two others found no association between HCQ and mortality. Findings from two meta-analyses showed that HCQ with Azithromycin increased the risk of mortality, with similar ORs of 2.5. The updated meta-analysis of experimental studies showed that the drugs were not effective in reducing mortality (RR 1.1, 95%CI 1.0-1.3, I2 = 0.0%), need for intensive care services (OR 1.1, 95%CI 0.9-1.4, I2 = 0.0%), virological cure (OR 1.5, 95%CI 0.5-4.4, I2 = 39.6%) or disease exacerbation (OR 1.2, 95%CI 0.3-5.9, I2 = 31.9%) but increased the odds of adverse events (OR 12,3, 95%CI 2.5-59.9, I2 = 76.6%). CONCLUSION: There is conclusive evidence that CQ and HCQ, with or without Azithromycin are not effective in treating COVID-19 or its exacerbation. REGISTRATION: PROSPERO: CRD42020191353.