scholarly journals Transmissibility of COVID-19 among Vaccinated Individuals: A Rapid Literature Review

2021 ◽  
Author(s):  
Oluwaseun Egunsola ◽  
Liza Mastikhina ◽  
Laura Dowsett ◽  
Brenlea Farkas ◽  
Mark Hofmeister ◽  
...  
Keyword(s):  
Viral Load ◽  
General Population ◽  
Observational Studies ◽  
Animal Studies ◽  
Asymptomatic Infection ◽  
Controlled Trials ◽  
Lower Viral Load ◽  
Full Dose ◽  
Cycle Threshold ◽  
Household Transmission

Objectives: This is an update of a previous report that examined literature published up to March 11th, 2021. Sixteen additional studies have been included in this update. The objective of this report is to identify comparative observational studies and randomized controlled trials (RCTs) evaluating the efficacy and effectiveness of COVID-19 vaccination in reducing forward transmission from vaccinated people, and studies examining the biological plausibility of vaccination-induced transmission reduction. Method: A search of databases, MEDLINE, Embase, L-OVE and the Cochrane Central Register of Controlled Trials was conducted to identify RCTs or comparative observational studies evaluating the efficacy and effectiveness of COVID-19 vaccination in the prevention of transmission, asymptomatic infections and transmissibility of COVID-19 among vaccinated persons. An additional search of grey literature was conducted. This search is current to May 4th, 2021. Results: In this update, 16 additional studies, including 9 human and 7 animal studies, were included. Therefore, this review examines a total of 33 included studies: 21 human studies and 12 preclinical animal studies. Evidence from two large household surveillance studies from the UK suggests that a single or full dose of AstraZeneca (AZ) and Pfizer-BioNtech (PfBnT) vaccines may prevent household transmission of COVID-19 after 14 days of vaccination by up to 54%. The AZ vaccine trials in the general population suggest that an initial low dose followed by a standard dose may provide up to 59% protection against asymptomatic or unknown infection, although efficacy against these outcomes was not demonstrated following two standard doses. PfBnT vaccine observational studies in the general population suggest up to 90% effectiveness against asymptomatic infection after seven or more days of full dose vaccination. Up to 75% effectiveness against asymptomatic infection was reported after full-dose in healthcare workers. Across RCTs examining asymptomatic infection in the general population, one dose of Moderna was shown to provide an efficacy of 61.4% against asymptomatic infection 21 days after the first dose; in another trial, the J&J vaccine had an efficacy of 74% 28 days after the first dose. Lastly, seven of eight studies found significantly increased cycle threshold, suggestive of lower viral load, in PfBnT or AZ vaccinated individuals compared with those who were unvaccinated. Conclusion: The AZ and PfBnT vaccines may prevent household transmission of COVID-19 after 14 days of vaccination. More studies have found the vaccines to significantly reduce the risk of asymptomatic infection and significantly increase cycle threshold, suggestive of lower viral load. Further research is needed to evaluate post-vaccination infectivity and transmission of both the wild type COVID-19 virus and the variants of concern from other jurisdictions.

scholarly journals Inferring SARS-CoV-2 variant within-host kinetics

2021 ◽  
Author(s):  
Baptiste Elie ◽  
Emmanuel Lecorche ◽  
Mircea T. Sofonea ◽  
Sabine Trombert ◽  
Vincent Foulogne ◽  
...  
Keyword(s):  
Viral Load ◽  
General Population ◽  
Host Population ◽  
Screening Tests ◽  
Infectious Period ◽  
Wild Type ◽  
Cycle Threshold ◽  
Transmission Data ◽  
Peak Viral Load ◽  
Period Duration

SARS-CoV-2 variants are causing epidemic rebounds in many countries. By analyzing longitudinal cycle threshold (Ct) values from screening tests in the general population and hospitals, we find that infections caused by variant lineages have higher peak viral load than wild type lineages and, for the B.1.1.7 lineage, have a longer infectious period duration. Linking within-host kinetics to transmission data suggests that infections caused by variants have higher transmission potentials and that their epidemiological fitness may depend on the demography of the host population.

257-OR: High Glucose Levels and Risk of Vascular Diseases—Observational Studies and Mendelian Randomization Studies of the General Population

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 257-OR
Author(s):  
FRIDA EMANUELSSON ◽  
SARAH MAROTT ◽  
ANNE TYBJAERG-HANSEN ◽  
BØRGE GRØNNE NORDESTGAARD ◽  
MARIANNE BENN
Keyword(s):  
General Population ◽  
High Glucose ◽  
Observational Studies ◽  
Mendelian Randomization ◽  
Vascular Diseases ◽  
Glucose Levels

scholarly journals Beta-blocker therapy in patients with COPD: a systematic literature review and meta-analysis with multiple treatment comparison

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Claudia Gulea ◽  
Rosita Zakeri ◽  
Vanessa Alderman ◽  
Alexander Morgan ◽  
Jack Ross ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Beta Blocker ◽  
Observational Studies ◽  
Beta Blockers ◽  
Meta Analysis ◽  
Controlled Trials ◽  
Life Outcomes ◽  
Blocker Therapy ◽  
Beta Blocker Therapy

Abstract Background Beta-blockers are associated with reduced mortality in patients with cardiovascular disease but are often under prescribed in those with concomitant COPD, due to concerns regarding respiratory side-effects. We investigated the effects of beta-blockers on outcomes in patients with COPD and explored within-class differences between different agents. Methods We searched the Cochrane Central Register of Controlled Trials, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Medline for observational studies and randomized controlled trials (RCTs) investigating the effects of beta-blocker exposure versus no exposure or placebo, in patients with COPD, with and without cardiovascular indications. A meta-analysis was performed to assess the association of beta-blocker therapy with acute exacerbations of COPD (AECOPD), and a network meta-analysis was conducted to investigate the effects of individual beta-blockers on FEV1. Mortality, all-cause hospitalization, and quality of life outcomes were narratively synthesized. Results We included 23 observational studies and 14 RCTs. In pooled observational data, beta-blocker therapy was associated with an overall reduced risk of AECOPD versus no therapy (HR 0.77, 95%CI 0.70 to 0.85). Among individual beta-blockers, only propranolol was associated with a relative reduction in FEV1 versus placebo, among 199 patients evaluated in RCTs. Narrative syntheses on mortality, all-cause hospitalization and quality of life outcomes indicated a high degree of heterogeneity in study design and patient characteristics but suggested no detrimental effects of beta-blocker therapy on these outcomes. Conclusion The class effect of beta-blockers remains generally positive in patients with COPD. Reduced rates of AECOPD, mortality, and improved quality of life were identified in observational studies, while propranolol was the only agent associated with a deterioration of lung function in RCTs.

scholarly journals Incidence of thrombotic complications in COVID-19

2021 ◽  
Author(s):  
William J. Jenner ◽  
Diana A. Gorog
Keyword(s):  
Intensive Care Unit ◽  
Observational Studies ◽  
Severity Of Illness ◽  
Controlled Trials ◽  
Thrombotic Risk ◽  
Randomized Controlled ◽  
Hospitalised Patients ◽  
High Incidence ◽  
Thrombotic Complications ◽  
Asymptomatic Individuals

AbstractA high incidence of thrombosis in hospitalised patients with COVID-19 was identified early during the pandemic. Accurately quantifying thrombotic risk may assist prognosis and guide appropriate thromboprophylaxis. Observational studies have estimated the rate of thrombosis in both hospitalised and non-hospitalised patients with COVID-19, and how this corresponds to the severity of illness. In this review, we provide an overview of the incidence and prevalence of arterial and venous thrombotic events in patients with COVID-19 and highlight the limitations in the studies to date. Asymptomatic individuals with COVID-19 and those with mild symptoms are at very low risk of thrombotic complications. However, rates of thrombosis are substantially increased in hospitalised patients, and are strikingly high in those patients who are critically-ill requiring treatment on the intensive care unit and especially those requiring extracorporeal membrane oxygenation. Clinicians managing such patients need to be aware of these risks and take appropriate steps with respect to thromboprophylaxis and heightened clinical vigilance. Large prospective observational studies will more accurately quantify thrombotic rate, and randomized controlled trials are currently investigating optimal thromboprophylactic strategies.

328 Insomnia in older HIV patients: a systematic review

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A131-A131
Author(s):  
Igor Freire ◽  
Miguel Meira e Cruz ◽  
Cristina Salles
Keyword(s):  
Systematic Review ◽  
General Population ◽  
Animal Studies ◽  
Advanced Age ◽  
Cochrane Library ◽  
Hiv Positive ◽  
Sleep Difficulty ◽  
Cross Sectional ◽  
Previous Diagnosis ◽  
Worse Prognosis

Abstract Introduction Insomnia is a common sleep disorder in elderly. Although the HIV-positive population have a similar life expectancy when compared to the general population, some factors may interact with immunity conditions and therefore contribute to a worse prognosis. Little is known however, about the frequency of insomnia in older HIV-positive patients. OBJECTIVE: To systematic review the prevalence of insomnia in older HIV-positive patients. Methods Systematic Review. Several databases were consulted (MEDLINE-PubMed, Embase, Cochrane Library, CINAHL, Web of Science, Scopus, SciELO, LILACS, and VHL) and manual searches were performed. The terms used for the search were related to prevalence, HIV, insomnia, and advanced age. The inclusion criteria were: cross-sectional, cohort, and longitudinal studies. The accepted data were in patients with the previous diagnosis of HIV in advanced age, those over 50 years; studies that report the frequency of insomnia or insomnia symptoms (accepted symptoms: difficulty in starting sleep, difficulty in maintaining sleep, multiple awakenings during sleep and early awakening). The criteria for exclusion were: clinical trials, animal studies, letters, abstracts, conference proceedings, studies with other sleep scales that did not include insomnia. Results There were 2805 publications found in the database and a further 10 articles were included manually. Of this total, four were included in this review, resulting in a total of 2,227 participants. The prevalence of insomnia in HIV-positive patients over 50 years varied from 12.5% to 76.5%. Conclusion The frequency of insomnia was higher in the profile of the population studied than in the general population. This should be clinically relevant in order to adequately treat and impact on the prognosis of those patient. Support (if any):

scholarly journals Analysis of Immunity to Febrile Malaria in Children That Distinguishes Immunity from Lack of Exposure

2009 ◽  
Vol 77 (5) ◽  
pp. 1917-1923 ◽  
Author(s):  
Philip Bejon ◽  
George Warimwe ◽  
Claire L. Mackintosh ◽  
Margaret J. Mackinnon ◽  
Sam M. Kinyanjui ◽  
...  
Keyword(s):  
Cell Surface ◽  
Antibody Response ◽  
Observational Studies ◽  
Asymptomatic Infection ◽  
Bed Nets ◽  
Bed Net ◽  
Red Cell ◽  
Vaccine Trials ◽  
Net Use ◽  
Malaria Episodes

ABSTRACT In studies of immunity to malaria, the absence of febrile malaria is commonly considered evidence of “protection.” However, apparent “protection” may be due to a lack of exposure to infective mosquito bites or due to immunity. We studied a cohort that was given curative antimalarials before monitoring began and documented newly acquired asymptomatic parasitemia and febrile malaria episodes during 3 months of surveillance. With increasing age, there was a shift away from febrile malaria to acquiring asymptomatic parasitemia, with no change in the overall incidence of infection. Antibodies to the infected red cell surface were associated with acquiring asymptomatic infection rather than febrile malaria or remaining uninfected. Bed net use was associated with remaining uninfected rather than acquiring asymptomatic infection or febrile malaria. These observations suggest that most uninfected children were unexposed rather than “immune.” Had they been immune, we would have expected the proportion of uninfected children to rise with age and that the uninfected children would have been distinguished from children with febrile malaria by the protective antibody response. We show that removing the less exposed children from conventional analyses clarifies the effects of immunity, transmission intensity, bed nets, and age. Observational studies and vaccine trials will have increased power if they differentiate between unexposed and immune children.

scholarly journals Measurement of long-term outcomes in observational and randomised controlled trials

2007 ◽  
Vol 191 (S50) ◽  
pp. s78-s84 ◽  
Author(s):  
Richard Hodgson ◽  
Chris Bushe ◽  
Robert Hunter
Keyword(s):  
Gold Standard ◽  
Observational Studies ◽  
Randomised Controlled Trials ◽  
Face Validity ◽  
Controlled Trials ◽  
Experimental Paradigm ◽  
Pragmatic Trials ◽  
Long Term Outcomes ◽  
Randomised Controlled

BackgroundRandomised controlled trials (RCTs) are the gold standard for evaluating treatment efficacy. However, the outcomes of RCTs often lackclinical utility and usually do not address real-world effectivenessAimsTo review how traditional RCTs may be triangulatedwith other methodologies such as observational studies and pragmatic trials by highlighting recently reported studies, outcomes used and their respective meritsMethodLiterature review focusing on drug treatmentResultsRecently reported observational and some pragmatic studies show a degree of consistency in reported results and use outcomes that have face validity for cliniciansConclusionsNo single experimental paradigm or outcome provides the necessary data to optimise treatment of mental illness in the clinical setting

scholarly journals Differential Kinetics of Cycle Threshold Values during Admission by Symptoms among Patients with Mild COVID-19: A Prospective Cohort Study

2021 ◽  
Vol 18 (15) ◽  
pp. 8181
Author(s):  
Teppei Sakano ◽  
Mitsuyoshi Urashima ◽  
Hiroyuki Takao ◽  
Kohei Takeshita ◽  
Hiroe Kobashi ◽  
...  
Keyword(s):  
Cohort Study ◽  
Viral Load ◽  
Prospective Cohort Study ◽  
Prospective Cohort ◽  
Polymerase Chain Reaction Test ◽  
Cycle Threshold ◽  
Viral Loads ◽  
Asymptomatic Patients ◽  
Asymptomatic Individuals ◽  
Chain Reaction Test

In the coronavirus disease 2019 (COVID-19) pandemic, more than half of the cases of transmission may occur via asymptomatic individuals, which makes it difficult to contain. However, whether viral load in the throat during admission is different between asymptomatic and symptomatic patients is not well known. By conducting a prospective cohort study of patients with asymptomatic or mild COVID-19, cycle threshold (Ct) values of the polymerase chain reaction test for COVID-19 were examined every other day during admission. The Ct values during admission increased more steadily in symptomatic patients and febrile patients than in asymptomatic patients, with significance (p = 0.01 and p = 0.004, respectively), although the Ct values as a whole were not significantly different between the two groups. Moreover, the Ct values as a whole were higher in patients with dysosmia/dysgeusia than in those without it (p = 0.02), whereas they were lower in patients with a headache than those without (p = 0.01). Patients who were IgG-positive at discharge maintained higher Ct values, e.g., more than 35, during admission than those with IgG-negative (p = 0.03). Assuming that viral load and Ct values are negatively associated, the viral loads as a whole and their changes by time may be different by symptoms and immune reaction, i.e., IgG-positive at discharge.

scholarly journals High-cited favorable studies for COVID-19 treatments ineffective in large trials

2022 ◽  
Author(s):  
John P.A. Ioannidis
Keyword(s):  
Clinical Trials ◽  
Randomized Controlled Trials ◽  
Clinical Studies ◽  
Observational Studies ◽  
Randomized Trials ◽  
Controlled Trials ◽  
Randomized Controlled ◽  
Wide Dissemination ◽  
Highly Cited Articles ◽  
Highly Cited

Importance. COVID-19 has resulted in massive production, publication and wide dissemination of clinical studies trying to identify effective treatments. However, several widely touted treatments failed to show effectiveness in large well-done randomized controlled trials (RCTs). Objective. To evaluate for COVID-19 treatments that showed no benefits in subsequent large RCTs how many of their most-cited clinical studies had declared favorable results for these interventions. Methods. Scopus (last update December 23, 2021) identified articles on lopinavir-ritonavir, hydroxycholoroquine/azithromycin, remdesivir, convalescent plasma, colchicine or interferon (index interventions) that represented clinical trials and that had received >150 citations. Their conclusions were assessed and correlated with study design features. The ten most recent citations for the most-cited article on each index intervention were examined on whether they were critical to the highly-cited study. Altmetric scores were also obtained. Findings. 40 articles of clinical studies on these index interventions had received >150 citations (7 exceeded 1,000 citations). 20/40 (50%) had favorable conclusions and 4 were equivocal. Highly-cited articles with favorable conclusions were rarely RCTs while those without favorable conclusions were mostly RCTs (3/20 vs 15/20, p=0.0003). Only 1 RCT with favorable conclusions had sample size >160. Citation counts correlated strongly with Altmetric scores, in particular news items. Only 9 (15%) of 60 recent citations to the most highly-cited studies with favorable or equivocal conclusions were critical to the highly-cited study. Conclusion. Many clinical studies with favorable conclusions for largely ineffective COVID-19 treatments are uncritically heavily cited and disseminated. Early observational studies and small randomized trials may cause spurious claims of effectiveness that get perpetuated.

scholarly journals SGLT2 inhibitors and the risk of diabetic ketoacidosis among adults with Type 2 Diabetes: A systematic review and meta-analysis

2021 ◽  
Author(s):  
Michael Colacci ◽  
John Fralick ◽  
Ayodele Odutayo ◽  
Michael Fralick
Keyword(s):  
Diabetic Ketoacidosis ◽  
Observational Studies ◽  
Randomized Trials ◽  
Meta Analysis ◽  
Sglt2 Inhibitor ◽  
Sglt2 Inhibitors ◽  
Controlled Trials ◽  
Absolute Rate ◽  
Randomized Controlled

Importance: The risk of diabetic ketoacidosis (DKA) with sodium-glucose cotransporter-2 (SGLT2) inhibitors is unclear. Objective: To examine the risk of DKA with SGLT2 inhibitors in both observational studies and large clinical trials. Data Sources: Searches of PubMed, EMBASE and CENTRAL (inception to 15 April 2019) without language restrictions; conference proceedings; and reference lists. Study Selection: Randomized controlled trials and observational studies that quantified the rate of diabetic ketoacidosis with an SGLT2 inhibitor in comparison to another diabetes medication or placebo. Data Extraction and Synthesis: Two independent investigators abstracted study data and assessed the quality of evidence. Data were pooled using random effects models with the Hartung-Knapp-Sidik-Jonkman method. Main Outcome and Measures: Absolute event rates and hazard ratios for diabetic ketoacidosis were extracted from each study. Results: Seven randomized trials encompassing 42,375 participants and five cohort studies encompassing 318,636 participants were selected. Among the 7 randomized controlled trials, the absolute rate of DKA among patients randomized to an SGLT2 inhibitor ranged from 0.6 to 2.2 events per 1000 person years. Four randomized trials were included in the meta-analysis, and compared to placebo or comparator medication, SGLT2 inhibitors had a 2.4-fold higher risk of DKA (Relative Risk [RR] = 2.46 [95% CI, 1.16-5.21]; I2 = 0%; P = 0.54). Among the 5 observational studies, the absolute rate of DKA associated with SGLT2 inhibitor use ranged from 0.6 to 4.9 per 1000 person years and a 1.7-fold higher rate of DKA compared to another diabetes medication (RR = 1.74 [95% CI, 1.01-2.93]; I2 = 45%; P = 0.12). Conclusions and Relevance: In adults with type 2 diabetes, SGLT2 inhibitors increase the risk of DKA in both observational studies and large randomized clinical trials. Registration: CRD42019146855 Funding Source: None

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