Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 142.792
Filter
1.
Talanta ; 252: 123809, 2023 Jan 15.
Article in English | MEDLINE | ID: mdl-35985192

ABSTRACT

Nucleic acid amplification tests (NAATs) such as quantitative real-time reverse transcriptase PCR (qRT-PCR) or isothermal NAATs (iNAATs) such as loop-mediated isothermal amplification (LAMP) require pure nucleic acid free of any polymerase inhibitors as its substrate. This in turn, warrants the use of spin-column mediated extraction with centralized high-speed centrifuges. Additionally, the utilization of centralized real-time fluorescence readout and TaqMan-like molecular probes in qRT-PCR and real-time LAMP add cost and restrict their deployment. To circumvent these disadvantages, we report a novel sample-to-answer workflow comprising an indirect sequence-specific magneto-extraction (also referred to as magnetocapture, magneto-preconcentration, or magneto-enrichment) for detecting SARS-CoV-2 nucleic acid. It was followed by in situ fluorescence or electrochemical LAMP. After in silico validation of the approach's sequence selectivity against SARS-CoV-2 variants of concern, the comparative performance of indirect and direct magnetocapture in detecting SARS-CoV-2 nucleic acid in the presence of excess host nucleic acid or serum was probed. After proven superior, the sensitivity of the indirect sequence-specific magnetocapture in conjunction with electrochemical LAMP was investigated. In each case, its sensitivity was assessed through the detection of clinically relevant 102 and 103 copies of target nucleic acid. Overall, a highly specific nucleic acid detection method was established that can be accommodated for either centralized real-time SYBR-based fluorescence LAMP or portable electrochemical LAMP.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , Sensitivity and Specificity , Nucleic Acid Amplification Techniques/methods , RNA, Viral/genetics
2.
Article in English | MEDLINE | ID: mdl-36396447

ABSTRACT

BACKGROUND AND OBJECTIVES: Some disease-modifying treatments impair response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in multiple sclerosis (MS), potentially increasing the risk of breakthrough infections. We aimed to investigate longitudinal SARS-CoV-2 antibody dynamics and memory B cells after 2 and 3 messenger RNA (mRNA) vaccine doses and their association with the risk of COVID-19 in patients with MS on different treatments over 1 year. METHODS: Prospective observational cohort study in patients with MS undergoing SARS-CoV-2 mRNA vaccinations. Antispike (anti-S) immunoglobulin G (IgG) titers were measured by chemiluminescence microparticle immunoassay. Frequencies of spike-specific memory B cells were measured on polyclonal stimulation of peripheral blood mononuclear cells and screening of secreted antibodies by ELISA. RESULTS: We recruited 120 patients with MS (58 on anti-CD20 antibodies, 9 on sphingosine 1-phosphate (S1P) receptor modulators, 15 on cladribine, 24 on teriflunomide (TFL), and 14 untreated) and collected 392 samples up to 10.8 months after 2 vaccine doses. When compared with untreated patients, anti-CD20 antibodies (ß = -2.07, p < 0.001) and S1P modulators (ß = -2.02, p < 0.001) were associated with lower anti-S IgG, while TFL and cladribine were not. Anti-S IgG decreased with months since vaccine (ß = -0.14, p < 0.001), independently of treatments. Within anti-CD20 patients, anti-S IgG remained higher in those with greater baseline B-cell counts and were not influenced by postvaccine anti-CD20 infusions. Anti-S IgG increase after a 3rd vaccine was mild on anti-CD20 and S1P modulators. Spike-specific memory B-cell responses were weaker on S1P modulators and anti-CD20 than on TFL and influenced by postvaccine anti-CD20 infusions. The frequency of breakthrough infections was comparable between DMTs, but the risk of COVID-19 was predicted by the last measured anti-S IgG titer before infection (OR = 0.56, 95% CI = 0.37-0.86, p = 0.008). DISCUSSION: Postvaccine anti-S IgG titers decrease over time regardless of MS treatment and are associated with breakthrough COVID-19. Both humoral and specific memory B-cell responses are diminished on S1P modulators. Within anti-CD20-treated patients, B-cell count at first vaccine determines anti-S IgG production, whereas postvaccine anti-CD20 infusions negatively affect spike-specific memory B cells.


Subject(s)
COVID-19 , Multiple Sclerosis , Humans , SARS-CoV-2 , COVID-19/prevention & control , Immunoglobulin G , Cladribine , Leukocytes, Mononuclear , Prospective Studies , Antigens, CD20 , RNA, Messenger
3.
J Exp Med ; 220(2)2023 Feb 06.
Article in English | MEDLINE | ID: mdl-36378226

ABSTRACT

CTL-mediated killing of virally infected or malignant cells is orchestrated at the immune synapse (IS). We hypothesized that SARS-CoV-2 may target lytic IS assembly to escape elimination. We show that human CD8+ T cells upregulate the expression of ACE2, the Spike receptor, during differentiation to CTLs. CTL preincubation with the Wuhan or Omicron Spike variants inhibits IS assembly and function, as shown by defective synaptic accumulation of TCRs and tyrosine phosphoproteins as well as defective centrosome and lytic granule polarization to the IS, resulting in impaired target cell killing and cytokine production. These defects were reversed by anti-Spike antibodies interfering with ACE2 binding and reproduced by ACE2 engagement by angiotensin II or anti-ACE2 antibodies, but not by the ACE2 product Ang (1-7). IS defects were also observed ex vivo in CTLs from COVID-19 patients. These results highlight a new strategy of immune evasion by SARS-CoV-2 based on the Spike-dependent, ACE2-mediated targeting of the lytic IS to prevent elimination of infected cells.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Humans , Angiotensin-Converting Enzyme 2 , SARS-CoV-2 , Peptidyl-Dipeptidase A/metabolism , Synapses/metabolism , Protein Binding
4.
Article in English | MEDLINE | ID: mdl-36411077

ABSTRACT

BACKGROUND AND OBJECTIVES: Acute inflammatory CNS diseases include neuromyelitis optica spectrum disorders (NMOSDs) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Both MOGAD and acute disseminated encephalomyelitis (ADEM) have been reported after vaccination. Consequently, the mass SARS-CoV-2 vaccination program could result in increased rates of these conditions. We described the features of patients presenting with new acute CNS demyelination resembling NMOSDs or MOGAD within 8 weeks of SARS-CoV-2 vaccination. METHODS: The study included a prospective case series of patients referred to highly specialized NMOSD services in the UK from the introduction of SARS-CoV-2 vaccination program up to May 2022. Twenty-five patients presented with new optic neuritis (ON) and/or transverse myelitis (TM) ± other CNS inflammation within 8 weeks of vaccination with either AstraZeneca (ChAdOx1S) or Pfizer (BNT162b2) vaccines. Their clinical records and paraclinical investigations including MRI scans were reviewed. Serologic testing for antibodies to myelin oligodendrocyte glycoprotein (MOG) and aquaporin 4 (AQP4) was performed using live cell-based assays. Patients' outcomes were graded good, moderate, or poor based on the last clinical assessment. RESULTS: Of 25 patients identified (median age 38 years, 14 female), 12 (48%) had MOG antibodies (MOGIgG+), 2 (8%) had aquaporin 4 antibodies (AQP4IgG+), and 11 (44%) had neither. Twelve of 14 (86%) antibody-positive patients received the ChAdOx1S vaccine. MOGIgG+ patients presented most commonly with TM (10/12, 83%), frequently in combination with ADEM-like brain/brainstem lesions (6/12, 50%). Transverse myelitis was longitudinally extensive in 7 of the 10 patients. A peak in new MOGAD cases in Spring 2021 was attributable to postvaccine cases. Both AQP4IgG+ patients presented with brain lesions and TM. Four of 6 (67%) seronegative ChAdOx1S recipients experienced longitudinally extensive TM (LETM) compared with 1 of 5 (20%) of the BNT162b2 group, and facial nerve inflammation was reported only in ChAdOx1S recipients (2/5, 40%). Guillain-Barre syndrome was confirmed in 1 seronegative ChAdOx1S recipient and suspected in another. DISCUSSION: ChAdOx1S was associated with 12/14 antibody-positive cases, the majority MOGAD. MOGAD patients presented atypically, only 2 with isolated ON (1 after BNT162b2 vaccine) but with frequent ADEM-like brain lesions and LETM. Within the seronegative group, phenotypic differences were observed between ChAdOx1S and BNT162b2 recipients. These observations might support a causative role of the ChAdOx1S vaccine in inflammatory CNS disease and particularly MOGAD. Further study of this cohort could provide insights into vaccine-associated immunopathology.


Subject(s)
COVID-19 , Encephalomyelitis, Acute Disseminated , Myelitis, Transverse , Neuromyelitis Optica , Optic Neuritis , Female , Humans , Myelin-Oligodendrocyte Glycoprotein , Aquaporin 4 , Myelitis, Transverse/etiology , COVID-19 Vaccines/adverse effects , SARS-CoV-2 , BNT162 Vaccine , COVID-19/prevention & control , Central Nervous System , Encephalomyelitis, Acute Disseminated/etiology , Vaccination/adverse effects , Inflammation
5.
J Environ Sci (China) ; 125: 843-850, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36375966

ABSTRACT

With a unique and large size of testing results of 1,842 samples collected from 12 wastewater treatment plants (WWTP) for 14 months through from low to high prevalence of COVID-19, the sensitivity of RT-qPCR detection of SARS-CoV-2 RNA in wastewater that correspond to the communities was computed by using Probit analysis. This study determined the number of new COVID-19 cases per 100,000 population required to detect SARS-CoV-2 RNA in wastewater at defined probabilities and provided an evidence-based framework of wastewater-based epidemiology surveillance (WBE). Input data were positive and negative test results of SARS-CoV-2 RNA in wastewater samples and the corresponding new COVID-19 case rates per 100,000 population served by each WWTP. The analyses determined that RT-qPCR-based SARS-CoV-2 RNA detection threshold at 50%, 80% and 99% probability required a median of 8 (range: 4-19), 18 (9-43), and 38 (17-97) of new COVID-19 cases /100,000, respectively. Namely, the positive detection rate at 50%, 80% and 99% probability were 0.01%, 0.02%, and 0.04% averagely for new cases in the population. This study improves understanding of the performance of WBE SARS-CoV-2 RNA detection using the large datasets and prolonged study period. Estimated COVID-19 burden at a community level that would result in a positive detection of SARS-CoV-2 in wastewater is critical to support WBE application as a supplementary warning/monitoring system for COVID-19 prevention and control.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2/genetics , Waste Water/analysis , RNA, Viral/genetics , RNA, Viral/analysis , Alberta/epidemiology
7.
Ann Ig ; 35(1): 49-60, 2023.
Article in English | MEDLINE | ID: mdl-35195240

ABSTRACT

Background: Co-infection rates increase in patients admitted to the Intensive Care Units. The aim of this study was to examine the Healthcare Associated Infections in critically ill adult patients infected with SARS-CoV-2. Methods: A retrospective observational study in adults with confirmed SARS-CoV-2 infection requiring intensive care unit admission was performed. From February 2020 to September 2021, healthcare records from a total of 118 patients were evaluated. Results: In the study period, 39 patients were diagnosed with at least 1 Healthcare Associated Infection (33.1%). The co-infection/co-colonisation rate >48 hours after admission was 29.0 per 1,000 person/days (95 % CI 19.1-33.9). A total of 94 isolates were identified, the most common being Klebsiella spp, Clostridium difficile, Acinetobacter baumanii and Enterococcus spp. Associated outcomes for Healthcare Associated Infections have been identified: age >64 years (p= .003), length of Intensive Care Unit stay> 7 days (p= .002), Type 2 Diabetes mellitus (p= .019), cardiovascular disease (p= .021), inserted central venous catheter (p= .014), intubation (p< .001), APACHE II score >25 (p< .001), mechanical ventilation 48 hours (p= .003), and inserted urinary catheter (p= .002). The overall fatality rate of patients included in the study was 41.5% (n= 49), and it was found to be significantly higher in patients who acquired a Healthcare Associated Infection (n=26/39, 66.7%) compared to those who did not acquire it (n= 23/79, 29.1%) (OR= 4.87; 95% CI = 2.14-11.10; p< .001). Conclusions: Our study showed high rates of Healthcare Associated Infections in critically ill adults with COVID-19. Associated factors for Healthcare Associated Infections acquisition and fatality in Intensive Care Units patients were identified as a good reason for a revision of existing infection control policies.


Subject(s)
COVID-19 , Coinfection , Cross Infection , Diabetes Mellitus, Type 2 , Adult , Humans , Middle Aged , COVID-19/epidemiology , Retrospective Studies , Critical Illness , SARS-CoV-2 , Coinfection/epidemiology , Intensive Care Units , Cross Infection/epidemiology
8.
Ann Ig ; 35(1): 39-48, 2023.
Article in English | MEDLINE | ID: mdl-35442385

ABSTRACT

Introduction: Healthcare workers on duty at the hospital are at high risk of COVID-19 infection. However, despite the introduction of risk-lowering practices in the hospital setting, there have been many cases of SARS-COV-2 infection among Health Care Workers. Fast and efficient contact tracing and Sars-CoV-2 PCR-based testing of the close contacts of Health Care Workers with confirmed infections are essential steps to limit nosocomial outbreaks. Methods: This cross-sectional study was conducted at Bari Policlinico General University-Hospital (Apulia, Italy) and describes the management of a cluster of SARS-COV-2 infections in three Operative Units. The contact tracing activities and the measures implemented to control the outbreak are described. Results: Among the 186 Health Care Workers active in the cluster setting, there were 9 (4.8%) confirmed cases, including the index case. Due to the outbreak, three Operative Units were closed to limit virus circulation. Health Care Workers with confirmed infections tested negative after a mean of 28.0±6.6 days (range: 13-37) and none required hospitalization. Conclusions: Protection of the health of Health Care Workers during the COVID-19 pandemic should be a public health priority. However, despite recent recommendations and the implementation of protective measures, SARS-COV-2 infections of Health Care Workers remain at a high rate, indicative of the continued high risk of cluster onset in the nosocomial setting.


Subject(s)
COVID-19 , Cross Infection , Humans , COVID-19/epidemiology , SARS-CoV-2 , Pandemics/prevention & control , Cross Infection/epidemiology , Cross Infection/prevention & control , Cross-Sectional Studies , Social Network Analysis , Health Personnel , Hospitals, University
9.
Ann Ig ; 35(1): 34-38, 2023.
Article in English | MEDLINE | ID: mdl-35452071

ABSTRACT

Background: As other indoor sports facilities, swimming pools were closed in Italy from March to May 2020 and from October 2020 to July 2021 due to the outbreak of the COVID-19 pandemic; access to these facilities was restricted to athletes of national relevance. This decision was based on "precautionary principles" and without evidence of a high risk of SARS-COV-2 circulation among swimming pools' attendants. The aim of this paper is to describe the pattern of SARS-COV-2 circulation among swimming athletes in Apulia (Southern Italy). Study design: The study aims to investigate the hypothesis that attending a pool increases the risk of SARS-COV-2 infection. The outcome measure is the incidence of SARS-COV-2 infection among swimming athletes compared with the general population. Methods: This is a retrospective cross-sectional study carried out in Apulia, Southern Italy. The study was performed through the analysis of both the database of the Italian Swimming Federation and the SARS-COV-2 infections in Apulia Region, from July 2020 to August 2021. Results: Among 2,939 federally licensed athletes, 221 had an history of SARS-COV-2 infection from July 2020 to August 2021, with an incidence of 75.2 /1,000. In the general Apulian population, during the same time span, the incidence of SARS-COV-2 infection was 67.3/1,000 and - considering the incidence rate ratio - there is no difference between the two populations (IRR=1.1; 95% CI=0.9-1.3; p>0.05). Conclusions: The incidence of SARS-COV-2 infection in Apulian swimmers showed no significant differences with the general population.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2 , Pandemics , Incidence , Swimming , Cross-Sectional Studies , Retrospective Studies , Italy/epidemiology , Athletes
10.
Ann Ig ; 35(1): 75-83, 2023.
Article in English | MEDLINE | ID: mdl-35532052

ABSTRACT

Background: Vaccination has saved millions of lives through the protection of individuals and populations from communicable diseases. Vaccine hesitancy, defined as the delay in acceptance or refusal of vaccines despite the availability of vaccination services, has become a growing global concern. The objective of this study was to investigate parents'/caregivers' hesitancy toward childhood vaccination and its predictors in Albania. Study design: A cross-sectional survey was conducted. Methods: The data comes from a survey conducted on a sample of parents/caregivers (89.6% mothers) of children aged 6 months to 8 years at health care vaccination centers in seven Albanian cities from December 2020 to February 2021. Parents/caregivers (one per child) were interviewed by trained healthcare staff using a standardized questionnaire on six main content domains, including immunization behavior, beliefs about vaccine safety and efficacy, attitudes about vaccines, vaccination confidence, estimation of vaccine delay, and the intention to immunize children against SARS-CoV-2, and a self-reported hesitancy. The Albanian Ministry of Health approved the questionnaire, after it was translated, validated and adapted to the local setting. Statistical analyses included independent sample t-tests (p<0.05) and a logistic regression (OR; 95% C.I.). Results: A total of 475 parents/caregivers of children aged from 6 months to 8 years, attending childhood vaccination in public health services, were interviewed. To the question "how hesitant you are about childhood vaccination", a high number of parents/caregivers (46%) responded that they do not feel hesitant at all, and 32% were not hesitant, a small number of parents/caregivers said they are very hesitant (5%) or somewhat hesitant (12%). A binary logistic model was fitted to the data to test the hypothesis regarding the relationship between parental vaccine hesitancy and possible predictors. A lower parental attitude toward childhood vaccines (OR = 3.7; 95% C.I. 1.102-12.421), a health center with a high vaccine delay (OR = 2.878; C.I. 95% 1.735-4.773), and low confidence in health staff information (OR = 2.042; 95% C.I. 1.156-3.605) were all independent predictors of parental vaccine hesitancy. Regarding intention to vaccinate children against COVID-19, when available, nearly 75% of parents/caregivers showed hesitancy. Conclusions: Our results highlighted the role of positive parents'/caregivers' attitudes toward childhood vaccines followed by high staff confidence and good health center organization in order to deal with vaccine hesitancy, particularly for traditional and well-known childhood vaccines. Nevertheless, the hesitancy can be a critical barrier for childhood vaccination when we have to introduce a new vaccine, as is demonstrated in the recent vaccination campaign against the ongoing pandemic of SARS-CoV2.


Subject(s)
COVID-19 , Vaccines , Child , Female , Humans , Caregivers , Cross-Sectional Studies , Vaccination Hesitancy , Albania , RNA, Viral , Health Knowledge, Attitudes, Practice , COVID-19/prevention & control , SARS-CoV-2 , Parents , Vaccination
11.
Ann Ig ; 35(1): 112-120, 2023.
Article in English | MEDLINE | ID: mdl-36222607

ABSTRACT

Background: The COVID-19 emergency has highlighted the importance of prevention systems and environ-mental microbiological monitoring as fundamental elements in the response to epidemics and other such threats to individual and collective health. The use of automated "No-touch" room disinfection systems eliminates or reduces the dependence on operators, thus allowing an improvement in the effectiveness of terminal disinfection. Study design: In the present study, we focused on possible SARS-CoV-2 contamination of surfaces of com-mercial services, and the effectiveness of ozone treatment on the virus. Methods: Analyses were conducted on 4-7 October and 27-30 December 2021 in four supermarkets in an Apulian city; supermarkets A and B were equipped with an ozonisation system, while C and D were without any environmental remediation. Results: SARS-CoV-2 RNA was detected by real-time RT-PCR only in December, in 6% of the surfaces tested, and all examined samples were found to be negative after viral culture, since no cytopathic effect was observed. A statistically significant difference emerged from the comparison of October vs. December (p = 0.0289), but no statistically significant difference (p = 0.6777) emerged from the comparison between supermarkets with and without the ozonisation system. Conclusions: Although no important changes were observed by treating the environments with ozonisation systems, further studies are needed to validate the effectiveness of environmental treatments with airborne disinfectants.


Subject(s)
COVID-19 , Ozone , Humans , SARS-CoV-2 , RNA, Viral , Disinfection , Ozone/pharmacology
12.
Life Sci Alliance ; 6(1)2023 Jan.
Article in English | MEDLINE | ID: mdl-36347544

ABSTRACT

Understanding the molecular mechanism underlying the rampant mutation of SARS-CoV-2 would help us control the COVID-19 pandemic. The APOBEC-mediated C-to-U deamination is a major mutation type in the SARS-CoV-2 genome. However, it is unclear whether the novel mutation rate u is higher for C-to-U than for other mutation types, and what the detailed driving force is. By analyzing the time course SARS-CoV-2 global population data, we found that C-to-U has the highest novel mutation rate u among all mutation types and that this u is still increasing with time (du/dt > 0). Novel C-to-U events, rather than other mutation types, have a preference over particular genomic regions. A less local RNA structure is correlated with a high novel C-to-U mutation rate. A cascade model nicely explains the du/dt > 0 for C-to-U deamination. In SARS-CoV-2, the RNA structure serves as the molecular basis of the extremely high and continuously accelerating C-to-U deamination rate. This mechanism is the driving force of the mutation, adaptation, and evolution of SARS-CoV-2. Our findings help us understand the dynamic evolution of the virus mutation rate.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Pandemics , Deamination , Genome, Viral/genetics , RNA
13.
Med Educ Online ; 28(1): 2143307, 2023 Dec.
Article in English | MEDLINE | ID: mdl-36369921

ABSTRACT

The COVID-19 pandemic transformed the final year of undergraduate medical education for thousands of medical students across the globe. Out of concern for spreading SARS-CoV-2 and conserving personal protective equipment, many students experienced declines in bedside clinical exposures. The perceived competency of this class within the context of the pandemic is unclear. We designed and distributed a survey to measure the degree to which recent medical school graduates from the USA felt clinically prepared on 13 core clinical skills. Of the 1283 graduates who matched at HCA Healthcare facilities, 90% (1156) completed the survey. In this national survey, most participants felt they were competent in their clinical skills. However, approximately one out of four soon-to-be residents felt they were clinically below where they should be with regard to calling consultations, performing procedures, and performing pelvic and rectal exams. One in five felt they were below where they should be with regard to safely transitioning care. These perceived deficits in important skill sets suggest the need for evaluation and revised educational approaches in these areas, especially when traditional in-person practical skills teaching and practice are disrupted.


Subject(s)
COVID-19 , Education, Medical , Internship and Residency , Physicians , Students, Medical , Humans , COVID-19/epidemiology , Pandemics , SARS-CoV-2
14.
J Theor Biol ; 557: 111334, 2023 Jan 21.
Article in English | MEDLINE | ID: mdl-36306828

ABSTRACT

The COVID-19 pandemic has underscored the need to understand the dynamics of SARS-CoV-2 respiratory infection and protection provided by the immune response. SARS-CoV-2 infections are characterized by a particularly high viral load, and further by the small number of inhaled virions sufficient to generate a high viral titer in the nasal passage a few days after exposure. SARS-CoV-2 specific antibodies (Ab), induced from vaccines, previous infection, or inhaled monoclonal Ab, have proven effective against SARS-CoV-2 infection. Our goal in this work is to model the protective mechanisms that Ab can provide and to assess the degree of protection from individual and combined mechanisms at different locations in the respiratory tract. Neutralization, in which Ab bind to virion spikes and inhibit them from binding to and infecting target cells, is one widely reported protective mechanism. A second mechanism of Ab protection is muco-trapping, in which Ab crosslink virions to domains on mucin polymers, effectively immobilizing them in the mucus layer. When muco-trapped, the continuous clearance of the mucus barrier by coordinated ciliary propulsion entrains the trapped viral load toward the esophagus to be swallowed. We model and simulate the protection provided by either and both mechanisms at different locations in the respiratory tract, parametrized by the Ab titer and binding-unbinding rates of Ab to viral spikes and mucin domains. Our results illustrate limits in the degree of protection by neutralizing Ab alone, the powerful protection afforded by muco-trapping Ab, and the potential for dual protection by muco-trapping and neutralizing Ab to arrest a SARS-CoV-2 infection. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Pandemics , Antibodies, Viral , Respiratory System , Mucins
15.
J Theor Biol ; 557: 111331, 2023 Jan 21.
Article in English | MEDLINE | ID: mdl-36309118

ABSTRACT

The emergence of SARS-CoV-2 saw severe detriments to public health being inflicted by COVID-19 disease throughout 2020. In the lead up to Christmas 2020, the UK Government sought an easement of social restrictions that would permit spending time with others over the Christmas period, whilst limiting the risk of spreading SARS-CoV-2. In November 2020, plans were published to allow individuals to socialise within 'Christmas bubbles' with friends and family. This policy involved a planned easing of restrictions in England between 23-27 December 2020, with Christmas bubbles allowing people from up to three households to meet throughout the holiday period. We estimated the epidemiological impact of both this and alternative bubble strategies that allowed extending contacts beyond the immediate household. We used a stochastic individual-based model for a synthetic population of 100,000 households, with demographic and SARS-CoV-2 epidemiological characteristics comparable to England as of November 2020. We evaluated five Christmas bubble scenarios for the period 23-27 December 2020, assuming our populations of households did not have symptomatic infection present and were not in isolation as the eased social restrictions began. Assessment comprised incidence and cumulative infection metrics. We tested the sensitivity of the results to a situation where it was possible for households to be in isolation at the beginning of the Christmas bubble period and also when there was lower adherence to testing, contact tracing and isolation interventions. We found that visiting family and friends over the holiday period for a shorter duration and in smaller groups was less risky than spending the entire five days together. The increases in infection from greater amounts of social mixing disproportionately impacted the eldest. We provide this account as an illustration of a real-time contribution of modelling insights to a scientific advisory group, the Scientific Pandemic Influenza Group on Modelling, Operational sub-group (SPI-M-O) for the Scientific Advisory Group for Emergencies (SAGE) in the UK, during the COVID-19 pandemic. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Pandemics , COVID-19/epidemiology , Contact Tracing/methods , Family Characteristics
16.
J Theor Biol ; 557: 111336, 2023 Jan 21.
Article in English | MEDLINE | ID: mdl-36323394

ABSTRACT

The COVID-19 epidemic has lasted for more than two years since the outbreak in late 2019. An urgent and challenging question is how to systematically evaluate epidemic developments in different countries, during different periods, and to determine which measures that could be implemented are key for successful epidemic prevention. In this study, SBD distance-based K-shape clustering and hierarchical clustering methods were used to analyse epidemics in Asian countries. For the hierarchical clustering, epidemic time series were divided into three periods (epidemics induced by the Original/Alpha, Delta and Omicron variants separately). Standard deviations, the Hurst index, mortality rates, peak value of confirmed cases per capita, average growth rates, and the control efficiency of each period were used to characterize the epidemics. In addition, the total numbers of cases in the different countries were analysed by correlation and regression in relation to 15 variables that could have impacts on COVID-19. Finally, some suggestions on prevention and control measures for each category of country are given. We found that the total numbers of cases per million of a population, total deaths per million and mortality rates were highly correlated with the proportion of people aged over 65 years, the prevalence of multiple diseases, and the national GDP. We also found significant associations between case numbers and vaccination rates, health expenditures, and stringency of control measures. Vaccinations have played a positive role in COVID-19, with a gradual decline in mortality rates in later periods, and are still playing protective roles against the Delta and Omicron strains. The stringency of control measures taken by a government is not an indicator of the appropriateness of a country's response to the outbreak, and a higher index does not necessarily mean more effective measures; a combination of factors such as national vaccination rates, the country's economic foundation and the availability of medical equipment is also needed. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".


Subject(s)
COVID-19 , Humans , Aged , COVID-19/epidemiology , SARS-CoV-2 , Pandemics , Asia/epidemiology
17.
J Theor Biol ; 557: 111335, 2023 Jan 21.
Article in English | MEDLINE | ID: mdl-36334850

ABSTRACT

Repeat asymptomatic testing in order to identify and quarantine infectious individuals has become a widely-used intervention to control SARS-CoV-2 transmission. In some workplaces, and in particular health and social care settings with vulnerable patients, regular asymptomatic testing has been deployed to staff to reduce the likelihood of workplace outbreaks. We have developed a model based on data available in the literature to predict the potential impact of repeat asymptomatic testing on SARS-CoV-2 transmission. The results highlight features that are important to consider when modelling testing interventions, including population heterogeneity of infectiousness and correlation with test-positive probability, as well as adherence behaviours in response to policy. Furthermore, the model based on the reduction in transmission potential presented here can be used to parameterise existing epidemiological models without them having to explicitly simulate the testing process. Overall, we find that even with different model paramterisations, in theory, regular asymptomatic testing is likely to be a highly effective measure to reduce transmission in workplaces, subject to adherence. This manuscript was submitted as part of a theme issue on "Modelling COVID-19 and Preparedness for Future Pandemics".


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/prevention & control , Policy , Disease Outbreaks , Quarantine
18.
Rev Med Inst Mex Seguro Soc ; 61(Suppl 1): 33-36, 2023 01 01.
Article in Spanish | MEDLINE | ID: mdl-36378084

ABSTRACT

Background: Since the beginning of the SARS-CoV-2 pandemic, identifying the COVID-19 pathophysiology not only has been addressed to applying diagnostic tests or preventing through vaccines, but also to the timely detection, especially of patients in risk groups such as those in transplants areas (renal, hematology, etcetera). In the case of these patients, using RT-PCR tests avoids putting them at risk by subjecting them to states of immunosuppression that could aggravate their situation if they were faced with an onset of a COVID-19 infection. Objective: To present the results of patients of a transplant unit tested for SARS-CoV-2. Material and methods: Descriptive, observational, cross-sectional, and retrolective study. Data of results of RT-PCR tests of patients who underwent transplantation from June 2021 to April 2022 in a third level hospital were collected. Results: 755 tests were done to patients who underwent transplantation. 384 (50.8%) were women. Out of all patients, only 73 (9.7%) were positive to SARS-CoV-2. Conclusions: Implementing RT-PCR tests as a transplant protocol to detect SARS-CoV-2 prevents fatal complications due to COVID infection to donors and receptors.


Introducción: desde que comenzó la pandemia por SARS-CoV-2, identificar la fisiopatología de la COVID-19 no solo se ha encaminado a aplicar pruebas diagnósticas o prevenir por medio de vacunas, sino también a la oportuna detección, sobre todo de pacientes de grupos de riesgo como los del área de trasplantes (renal, hematológico, etcétera). En el caso de estos pacientes, usar pruebas como la RT-PCR evita someterlos a estados de inmunosupresión que podrían agravar la situación en caso de que se encuentren ante un inicio de la infección por COVID-19. Objetivo: exponer los resultados de las pruebas de SARS-CoV-2 aplicadas a pacientes de una unidad de trasplantes. Material y métodos: estudio descriptivo, observacional, transversal y retrolectivo. Se recolectaron los datos de los resultados de las pruebas de RT-PCR para SARS-CoV-2 de pacientes sometidos a trasplante de junio de 2021 a abril de 2022 en un hospital de tercer nivel. Resultados: se hicieron 755 pruebas a los pacientes sometidos a trasplante; 384 (50.8%) fueron mujeres. De todos los pacientes, solo 73 (9.7%) fueron positivos a SARS-CoV-2. Conclusiones: implementar pruebas RT-PCR para detectar el SARS-CoV-2 como protocolo de trasplante previene complicaciones fatales derivadas de la infección por COVID a los donadores y a los receptores.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Female , Male , COVID-19/diagnosis , COVID-19/prevention & control , Cross-Sectional Studies , Pandemics/prevention & control , Polymerase Chain Reaction
19.
Rev Med Inst Mex Seguro Soc ; 61(Suppl 1): 28-32, 2023 01 01.
Article in Spanish | MEDLINE | ID: mdl-36378067

ABSTRACT

Background: COVID-19 pandemic spread around the world swiftly; there are several diagnostic strategies available. Health workers, especially medical residents (MR), are a high-risk population for acquiring this infection. Objective: To estimate the seroprevalence of antibodies against SARS-CoV-2 and the associated factors in MR of a third level hospital. Material and methods: 330 MR from different specialties were evaluated with a questionnaire and collection of blood samples for analysis by microparticle chemiluminescent immunoassay. The prevalence of previous infection was defined by seropositivity of these antibodies. Descriptive statistics and concordance between the RT-PCR tests and the presence of anti-SARS-CoV-2 IgG were used. Results: Of 330 MR, 84.5% actively participated in COVID patient care. One out of 3 reported symptoms of COVID-19; in 67.6% the possible site of infection was a hospital setting not associated with the COVID area. Out of 71 symptomatic subjects, 61.9% underwent RT-PCR against SARS-CoV-2; 20 were positive. In 15.8% of the total, the presence of anti-SARS-CoV-2 IgG antibodies was determined. Only 1 out of 3 subjects with a positive PCR had antibodies, and 11.3% of the cases, even with a positive RT-PCR test, did not develop humoral immunity. Conclusions: The seroprevalence was lower than that reported at the national level, potentially due to protection measures. The main risk factor was contact with the virus in areas of the hospital not related to COVID, making it imperative to reinforce security protocols in those spaces.


Introducción: la pandemia por COVID-19 se extendió rápidamente a nivel mundial; hay disponibles varias estrategias de diagnóstico. Los trabajadores de la salud, en especial los médicos residentes (MR), son una población de alto riesgo para adquirir dicha infección. Objetivo: estimar la seroprevalencia de anticuerpos contra el SARS-CoV-2 y los factores asociados en los MR de un hospital de tercer nivel. Material y métodos: se evaluaron 330 MR de diferentes especialidades con un cuestionario y recolección de muestras de sangre para análisis mediante un inmunoensayo quimioluminiscente de micropartículas. La prevalencia de infección previa se definió por seropositividad de estos anticuerpos. Se utilizó estadística descriptiva y concordancia entre las pruebas RT-PCR y presencia de IgG anti-SARS-CoV-2. Resultados: de los 330 MR, 84.5% participó activamente en atención de pacientes COVID. Uno de cada tres refirió síntomas de COVID-19; 67.6% tuvo posible sitio de contagio en ámbito hospitalario no asociado a Área COVID. De los 71 sujetos sintomáticos, 61.9% se realizaron RT-PCR; 20 fueron positivas. En 15.8% del total se determinó la presencia de anticuerpos IgG anti-SARS-CoV-2. Solo uno de cada tres sujetos con PCR positiva presentó anticuerpos y 11.3% de los casos, aun con RT-PCR positiva, no desarrolló inmunidad humoral. Conclusiones: la seroprevalencia fue menor que la reportada a nivel nacional, potencialmente por medidas de protección. El principal factor de riesgo fue el contacto con el virus en áreas del hospital no relacionadas a COVID, por lo que es imperativo reforzar los protocolos de seguridad en esos espacios.


Subject(s)
COVID-19 , Physicians , Humans , Seroepidemiologic Studies , SARS-CoV-2 , Pandemics , COVID-19/diagnosis , COVID-19/epidemiology , Antibodies, Viral , Immunoglobulin G , Health Personnel
20.
J Infect Chemother ; 29(1): 15-19, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36089257

ABSTRACT

INTRODUCTION: Anterior nasal sampling (AN) might be more convenient for patients than NP sampling to diagnose coronavirus disease. This study investigated the feasibility of rapid antigen tests for AN sampling, and the factors affecting the test accuracy. METHODS: This single-center prospective study evaluated one qualitative (ESP) and two quantitative (LUMI and LUMI-P) rapid antigen tests using AN and NP swabs. Symptomatic patients aged 20 years or older, who were considered eligible for reverse-transcription quantitative polymerase chain reaction using NP samples within 9 days of onset were recruited. Sensitivity, specificity, and positive and negative concordance rates between AN and NP samples were assessed for the rapid antigen tests. We investigated the characteristics that affected the concordance between AN and NP sampling results. RESULTS: A total of 128 cases were recruited, including 28 positive samples and 96 negative samples. The sensitivity and specificity of AN samples using ESP were 0.81 and 1.00, while those of NP samples were 0.94 and 1.00. The sensitivity of AN and NP samples was 0.91 and 0.97, respectively, and specificity was 1.00, for both LUMI and LUMI-P. The positive concordance rates of AN to NP sampling were 0.87, 0.94, and 0.85 for ESP, LUMI, and LUMI-P, respectively. No factor had a significant effect on the concordance between the sampling methods. CONCLUSIONS: ESP, LUMI, and LUMI-P showed practical diagnostic accuracy for AN sampling compared to NP sampling. There was no significant factor affecting the concordance between AN and NP sampling for these rapid antigen tests.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Prospective Studies , COVID-19/diagnosis , COVID-19 Testing , Sensitivity and Specificity , Nasopharynx
SELECTION OF CITATIONS
SEARCH DETAIL
...