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OBJECTIVES: To examine the differences in durability and its determinants of humoral immunity following 2- and 3-dose COVID-19 vaccination. METHODS: Throughout the pandemic, we evaluated the anti-spike IgG antibody titers of 2- and 3-dose mRNA vaccine recipients over time among the staff of a medical and research center in Tokyo. Linear mixed models were used to estimate trajectories of antibody titers from 14 to 180 days after the last immune-conferred event (vaccination or infection) and compare antibody waning rates across prior infection and vaccination status, and across background factors in infection-naïve participants. RESULTS: A total of 6901 measurements from 2964 participants (median age, 35 years; 30% male) were analyzed. Antibody waning rate (percentage per 30 days [95% CI]) was slower after 3 doses (25% [23-26]) than 2 doses (36% [35-37]). Participants with hybrid immunity (vaccination and infection) had further slower waning rates: 2-dose plus infection (16% [9-22]); 3-dose plus infection (21% [17-25]). Older age, male sex, obesity, coexisting diseases, immunosuppressant use, smoking, and alcohol drinking were associated with lower antibody titers, whereas these associations disappeared after 3 doses, except for sex (lower in female participants) and immunosuppressant use. Antibody waned slightly faster in older participants, females, and alcohol drinkers after 2 doses, whereas it did not differ after 3 doses across except sex. DISCUSSION: The 3-dose mRNA vaccine conferred higher durable antibody titers, and previous infection modestly enhanced its durability. The antibody levels at a given time point and waning speed after 2 doses differed across background factors; however, these differences mostly diminished after 3 doses.
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Purpose: The purpose of this study is to examine what makes some firms, but not others, see a crisis as an opportunity to become entrepreneurial. Specifically, it examines how two key capabilities for durability—(unabsorbed) slack resources and external market networks—influence small and medium-sized enterprises (SMEs)' "opportunity confidence”, a term recently coined to denote the subjective assessment of the extent to which a crisis is a good (bad) basis for entrepreneurial activities, such as the introduction of new products/services and new market entry. Methodology: Analysis of hand-collected survey data from 138 SMEs in Greece — a country hit hard by the 2008 economic crisis. Findings: The findings reveal that an SME's number of network contacts has a positive effect on opportunity confidence, whereas firm slack resources lack a direct effect. It is, in fact, at low levels of firm slack resources that network returns are higher, especially for older firms. An extension to the main analysis also shows that opportunity confidence is linked to firm sales growth. Practical implications: Understanding what makes some firms, but not others, see a crisis as an opportunity will help build an extensive and solid knowledge base and get ready for the next big (or small) crisis, which is inevitable to occur. Besides the grants and subsidies that policymakers often provide to SMEs in times of crisis, they may also need to consider organizing actions that support the extraversion and networking of SMEs—that can be done in a variety of ways due to the rise of teleworking and online collaboration platforms since the onset of the recent COVID-19 pandemic. Originality/value: This paper draws linkages between the "external enabler perspective” and the burgeoning resilience literature and illustrates empirically what makes some SMEs, but not others, view an economic crisis as a good basis for entrepreneurial activities—that is a manifestation of early-stage entrepreneurial behavior and a necessary condition before taking entrepreneurial action in times of crisis. By so doing, this study extends research on resilience that has explained the role of "capabilities for durability” as a means of surviving through a crisis by revealing that these capabilities do not necessarily translate into capabilities for renewal that will help firms to bounce forward in response to the crisis. It also points to the "dark side” of capabilities for durability and, by implication, of resilience. © 2023, Emerald Publishing Limited.
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Existing indoor closed ultraviolet-C (UVC) air purifiers (UVC in a box) have faced technological challenges during the COVID-19 breakout, owing to demands of low energy consumption, high flow rates, and high kill rates at the same time. A new conceptual design of a novel UVC-LED (light-emitting diode) air purifier for a low-cost solution to mitigate airborne diseases is proposed. The concept focuses on performance and robustness. It contains a dust-filter assembly, an innovative UVC chamber, and a fan. The low-cost dust filter aims to suppress dust accumulation in the UVC chamber to ensure durability and is conceptually shown to be easily replaced while mitigating any possible contamination. The chamber includes novel turbulence-generating grids and a novel LED arrangement. The turbulent generator promotes air mixing, while the LEDs inactivate the pathogens at a high flow rate and sufficient kill rate. The conceptual design is portable and can fit into ventilation ducts. Computational fluid dynamics and UVC ray methods were used for analysis. The design produces a kill rate above 97% for COVID and tuberculosis and above 92% for influenza A at a flow rate of 100 L/s and power consumption of less than 300 W. An analysis of the dust-filter performance yields the irradiation and flow fields.
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In this longitudinal prospective cohort of healthy adults in the United States, we found that coronavirus disease 2019 messenger RNA primary series and booster vaccinations elicited high titers of broadly cross-reactive neutralizing and antibody-dependent cell-mediated cytotoxicity antibodies, which gradually waned over 6 months, particularly against severe acute respiratory syndrome coronavirus 2 variants. These data support the indication for a subsequent booster vaccination.
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The Covid-19 pandemic has sparked global fretfulness. The concern is that the virus is spreading too far, too fast and medical scientists can't seem to find a way to contain it. Juan Dumois, a pediatric infectious-diseases physician at Johns Hopkins All Children's Hospital in St. Petersburg, Florida reported that "coronavirus in general will last a lot longer on a solid, nonporous surface compared to porous fabrics". He also suggested they would survive for longer on artificial fibres such as polyester rather than cotton, which is one of the mediums for spreading infection. In concurrence with an increasing public awareness of infectious diseases, the textile industry, including Sarex, would like to re-introduce two of its effective antimicrobial agents which are effective against a broad spectrum of microbes, pathogens and viruses. In this study, Sarex have treated various textile substrates - cotton, polyester and polyamide fabrics - with these anti-microbial agents and have tested them for durability using the AATCC100 test method. The results are very encouraging and can help in controlling the spread of the infections, thus contributing to the well-being of humankind. © 2020 World Textile Information Network. All rights reserved.
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Health awareness has increased worldwide since the COVID 2019 pandemic, creating a strong demand for wearable electronics. Wearable sensors for monitoring a patient's health are prevalent to reduce medical costs and decrease in-person clinic visits. Integrating electronics into clothes is challenging because most fabrics are porous and incompatible with the existing manufacturing methods, such as screen printing. The indirect printing method was employed to fabricate electrical circuitry on a textile substrate by printing it on a heat transfer polymer (HTP) and attaching it to the target cloths by stitching or glueing. Such a fabrication process has the potential to lead the way in developing new intelligent clothes. However, the durability of the printed circuitry in this manufacturing process on a cloth is still unknown and requires investigation. Therefore, this paper's objective is to study the durability of printed circuitries on fabric by applying constant cyclic loading. The test vehicle is a printed conductive silver interdigitating circuitry on fabric. Another test vehicle on a polyethylene terephthalate (PET) substrate was fabricated for a benchmark. A constant cyclic loading at 1Hz at a 50% duty cycle was applied to the test vehicles 100,000 times. The printed circuitry was monitored by logging the voltage in an electrical voltage divider configuration while the sensor was pressed and released. The result indicates that the fabric test vehicle can still function after the 100,000 cycles of the cyclic loading test and is comparable to that on the PET substrate. The recorded voltage-to-force values of the printed sensor on the fabric drifted upward and downward up to 3% over the loading cycles. The optical microscope observation on the cyclic loading samples showed signs of shear stresses on the printed silver and electrically conductive films, which could cause the tips of the silver interdigitating fingers to shatter. The study indicates that the properly manufactured circuits on fabric can be reliable and utilized for wearable applications. © 2022 IEEE.
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BACKGROUND: Restorative neurostimulation is a rehabilitative treatment for patients with refractory chronic low back pain (CLBP) associated with dysfunction of the lumbar multifidus muscle resulting in impaired neuromuscular control. The ReActiv8-B randomized, sham-controlled trial provided evidence of the effectiveness and safety of an implanted, restorative neurostimulator. The two-year analysis previously published in this journal demonstrated accrual of clinical benefits and long-term durability. OBJECTIVE: Evaluation of three-year effectiveness and safety in patients with refractory, disabling CLBP secondary to multifidus muscle dysfunction and no indications for spine surgery. MATERIALS AND METHODS: Prospective, observational follow-up of the 204 implanted trial participants. Low back pain visual analog scale (VAS), Oswestry Disability Index (ODI), EuroQol quality of life survey, and opioid intake were assessed at baseline, six months, and one, two, and three years after activation. The mixed-effects model repeated measures approach was used to provide implicit imputations of missing data for continuous outcomes and multiple imputation for proportion estimates. RESULTS: Data were collected from 133 participants, and 16 patients missed their three-year follow-up because of coronavirus disease restrictions but remain available for future follow-up. A total of 62% of participants had a ≥ 70% VAS reduction, and 67% reported CLBP resolution (VAS ≤ 2.5cm); 63% had a reduction in ODI of ≥ 20 points; 83% had improvements of ≥ 50% in VAS and/or ≥ 20 points in ODI, and 56% had these substantial improvements in both VAS and ODI. A total of 71% (36/51) participants on opioids at baseline had voluntarily discontinued (49%) or reduced (22%) opioid intake. The attenuation of effectiveness in the imputed (N = 204) analyses was relatively small and did not affect the statistical significance and clinical relevance of these results. The safety profile remains favorable, and no lead migrations have been observed to date. CONCLUSION: At three years, 83% of participants experienced clinically substantial improvements in pain, disability, or both. The results confirm the long-term effectiveness, durability, and safety of restorative neurostimulation in patients with disabling CLBP associated with multifidus muscle dysfunction. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT02577354.
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Disposable facemasks are a primary tool to prevent the transmission of SARS-COV-2 during the COVID-19 pandemic. However, plastic waste generated from their disposal represents a significant environmental problem that can be reduced by maximizing the service life of disposable masks. We evaluated the effect of repeated wearing on the fitted filtration efficiency (FFE) of N95, KF94, KN95, and procedure/surgical masks. The FFEs of masks were compared following extended wearing with and without washing. Results reveal that most disposable facemasks can retain a high level of their baseline FFE after extended wearing, even after 40 h of wearing. Laundering disposable masks degraded FFE in some instances. We conclude that the durability of disposable facemask performance is considerably longer than their intended single use indication, suggesting that reusing disposable masks is a safe means of reducing plastic waste in the environment.
Subject(s)
COVID-19 , Masks , COVID-19/prevention & control , Humans , Pandemics/prevention & control , Plastics , SARS-CoV-2ABSTRACT
Wearing a face mask is strongly advised to prevent the spread of the virus causing the COVID-19 pandemic, though masks have produced a tremendous amount of waste. As masks contain polypropylene and other plastics products, total degradation is not achievable, and masks may remain in the form of microplastics for several years in the environment. Therefore, this urgent issue ought to be addressed by properly handling waste face masks to limit their environmental impact. In relation to this goal, a novel application of recycled mask fiber (MF) derived from COVID-19 single-use surgical face masks (i.e., shredded mask fiber-SMF and cut mask fiber-CMF) has been undertaken. Eighteen mortar mixes (9 for water and 9 for 10% CO2 concentration curing) were fabricated at 0%, 0.5%, 1.0%, 1.5%, and 2.0% of both SMF and CMF by volume of ordinary Portland cement-based mortar. The compressive strength, flexural strength, ultrasonic pulse velocity, shrinkage, carbonation degree, permeable voids, and water absorption capabilities were assessed. The outcomes reveal that the compressive strength decreased with an increased percentage of MFs due to increased voids of the mixes with MFs as compared to a control mix. In contrast, significantly higher flexural strength was noted for the mortar with MFs, which is augmented with an increased percentage of MFs. Furthermore, the inclusion of MFs decreased the shrinkage of the mortar compared to the control mix. It was also found that MFs dramatically diminished the water absorption rate compared to the control mix, which reveals that MFs can enhance the durability of the mortar. © 2023 Elsevier Ltd
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Purpose>Coronavirus disease-2019 (COVID-19) is becoming a crucial health problem worldwide. Continued and high-speed mutations of this virus result in the appearance of new manifestations, making the control of this disease difficult. It has been shown that well-nourished patients have strong immune systems who mostly have short-term hospitalization compared to others. The purpose of this study is to review the major nutrients involved in the immune system reinforcement and to explain nutritional aspects during the recovery of COVID-19.Design/methodology/approach>In this review paper, the mechanistic role of nutrients in boosting the immune system and the nutritional aspects during the recovery of COVID-19 patients were discussed. Papers indexed in scientific databases were searched using antioxidants, COVID-19, inflammation, immune system, macronutrient, micronutrient and probiotic as keywords from 2000 to 2022.Findings>Because of the adverse effects of drugs like thrombosis, pulmonary embolism and hypercholesterolemia, a balanced diet with enough concentrations of energy and macronutrients could increase the patient's durability. The inflammatory cytokines in a vicious cycle delay patients' rehabilitation. The main mechanistic roles of micronutrients are attributed to the downregulation of virus replication and are involved in energy homeostasis. Dysbiosis is defined as another disturbance among COVID-19 patients, and supplementation with beneficial strains of probiotics helps to exert anti-inflammatory effects in this regard. Being on a well-planned diet with anti-inflammatory properties could reverse cytokine storms as the major feature of COVID-19. Future studies are needed to determine the safe and effective dose of dietary factors to control the COVID-19 patients.Originality/value>Being on a well-planned diet with anti-inflammatory properties could reverse cytokine storms as the major feature of COVID-19. Future studies are needed to determine the safe and effective dose of dietary factors to control the COVID-19 patients.
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BACKGROUND: BNT162b2 (Pfizer/BioNTech, Cominarty) and mRNA-1273 (Moderna, Spikevax) are mRNA vaccines that elicit antibodies against the SARS-CoV-2 spike receptor-binding domain (S-RBD) and have been approved by the Food and Drug Administration (FDA) to combat the COVID-19 pandemic. Because vaccine efficacy and antibody levels waned over time after the two-shot primary series, the FDA authorized a booster (third) dose for both mRNA vaccines to adults in the fall of 2021. OBJECTIVE: We sought to assess the magnitude and durability of S-RBD IgG after the booster mRNA vaccine dose in comparison to the primary series. We also compared S-RBD IgG levels after BNT162b2 and mRNA-1273 boosters and explored effects of age and prior infection. METHODS: Surrounding receipt of the second and third homologous mRNA vaccine doses, adults in an employee-based cohort provided serum and completed questionnaires, including information about prior COVID-19 infection. IgG to S-RBD was measured using an ImmunoCAP-based system. A subset of samples were assayed for IgG to SARS-CoV-2 nucleocapsid by commercial assay. RESULTS: 228 subjects had samples collected between 7 and 150 days after their primary series vaccine, and 117 subjects had samples collected in the same time frame after their boost. Antibody levels 7-31 days after the primary series and booster were similar, but S-RBD IgG was more durable over time after the boost, regardless of prior infection status. In addition, mRNA-1273 post-boost antibody levels exceeded BNT162b2 out to 5 months. CONCLUSION: COVID-19 mRNA vaccine boosters increase antibody durability, suggesting enhanced long-term clinical protection from SARS-CoV-2 infection compared to the two-shot regimen.
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COVID-19 vaccines are effective, but breakthrough infections have been increasingly reported. We conducted a test-negative case-control study to assess the durability of protection against symptomatic infection after vaccination with mRNA-1273. We fit conditional logistic regression (CLR) models stratified on residential county and calendar date of SARS-CoV-2 PCR testing to assess the association between the time elapsed since vaccination and the odds of symptomatic infection, adjusted for several covariates. There were 2,364 symptomatic individuals who had a positive SARS-CoV-2 PCR test after full vaccination with mRNA-1273 ("cases") and 12,949 symptomatic individuals who contributed 15,087 negative tests after full vaccination ("controls"). The odds of symptomatic infection were significantly higher 250 days after full vaccination compared to the date of full vaccination (Odds Ratio [OR]: 2.47, 95% confidence interval [CI]: 1.19-5.13). The odds of non-COVID-19 associated hospitalization and non-COVID-19 pneumonia (negative control outcomes) remained relatively stable over the same time interval (Day 250 ORNon-COVID Hospitalization: 0.68, 95% CI: 0.47-1.0; Day 250 ORNon-COVID Pneumonia: 1.11, 95% CI: 0.24-5.2). The odds of symptomatic infection remained significantly lower almost 300 days after the first mRNA-1273 dose as compared to 4 days after the first dose, when immune protection approximates the unvaccinated state (OR: 0.26, 95% CI: 0.17-0.39). Low rates of COVID-19 associated hospitalization or death in this cohort precluded analyses of these severe outcomes. In summary, mRNA-1273 robustly protected against symptomatic SARS-CoV-2 infection at least 8 months after full vaccination, but the degree of protection waned over this time period.
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In the present study, selenium nanoparticles were synthesized in situ on alkali-activated cotton fabric using guava leaf extract as a reducing agent. The synthesis was monitored by a change in color of fabric from white to light brick red. The UV-DRS analysis confirms the coating of Se NPs on cotton. The XRD, FT-IR, and SEM-EDX characterization techniques were used to analyze the nanoparticles on cotton fabric. The peak at 788 cm−1 in FT-IR confirms the formation of Se NPs on cotton fabric. The XRD analysis confirms that the average crystallite size of as-prepared nanoparticle is ~17 nm. SEM-EDX analysis shows the successful coating of Se NPs on coated fabric. ICP-OES studies confirm 3.65 mg/g of selenium nanoparticles were present on the fabric. The Se-coated-30 showed a larger zone of inhibition against Gram-positive S. aureus (32 mm) compared to Gram-negative strains of E. coli (16 mm) and K. pneumoniae (26 mm). The fabric was also tested against the fungi C. glabrata (45 mm), C. tropicalis (35 mm), and C. albicans (35 mm) and results indicate it is more effective against fungal compared to bacterial strains. The coated fabric inhibits biofilm formation of C. albicans (99%), S. aureus (78%), and E. coli (58%). The results demonstrated excellent antibacterial, antifungal, and antibiofilm activities of the Se-coated-30. The prepared fabric has the potential to be used in medicinal applications and is both ecofriendly and cost effective.
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Wearing a face mask is strongly advised to prevent the spread of the virus causing the COVID-19 pandemic, though masks have produced a tremendous amount of waste. As masks contain polypropylene and other plastics products, total degradation is not achievable, and masks may remain in the form of microplastics for several years in the environment. Therefore, this urgent issue ought to be addressed by properly handling waste face masks to limit their environmental impact. In relation to this goal, a novel application of recycled mask fiber (MF) derived from COVID-19 single-use surgical face masks (i.e., shredded mask fiber-SMF and cut mask fiber-CMF) has been undertaken. Eighteen mortar mixes (9 for water and 9 for 10% CO2 concentration curing) were fabricated at 0%, 0.5%, 1.0%, 1.5%, and 2.0% of both SMF and CMF by volume of ordinary Portland cement-based mortar. The compressive strength, flexural strength, ultrasonic pulse velocity, shrinkage, carbonation degree, permeable voids, and water absorption capabilities were assessed. The outcomes reveal that the compressive strength decreased with an increased percentage of MFs due to increased voids of the mixes with MFs as compared to a control mix. In contrast, significantly higher flexural strength was noted for the mortar with MFs, which is augmented with an increased percentage of MFs. Furthermore, the inclusion of MFs decreased the shrinkage of the mortar compared to the control mix. It was also found that MFs dramatically diminished the water absorption rate compared to the control mix, which reveals that MFs can enhance the durability of the mortar.
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Support treatment for patients with severe Covid19 symptoms is based on mechanical ventilation. As a result of the spread of the coronavirus, various medical institutions found it necessary to acquire more mechanical ventilators, causing an increase in the demand for their production. The production, distribution, and use conditions present a potential medium- and long-term risk concerning the equipment’s operation, safety, and effectiveness. In the face of the pandemic, the care that must be implemented to guarantee patient safety, the effectiveness of the equipment, and the quality of care, should be a high priority. This paper presents a first approach to analyzing the causes that can lead to a potential state of obsolescence in mechanical ventilators used to care for patients with Covid19. We collected information about mechanical ventilators, identified the factors that may cause a failure in the device, applied Multi-Criteria Decision Analysis for three possible outcomes, and compared the results with the expert opinion of clinical engineers. We found a total of 30 factors and classified them into associated, operation, and external concerning the ventilator. The results show that the factors found are associated with the technical field. The knowledge of the operation of the equipment’s subsystems and familiarity with its components is essential. The contrast with the expert opinion and the non-inclusion of factors such as the economic ones led to the development of more in-depth work on this topic. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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Background: More effective vaccine candidates against variants of concern as a booster dose are needed in people primed with two-dose inactivated COVID-19 vaccines. Methods: This randomised, double-blinded, investigator-initiated phase 2 trial aims to evaluate immunogenicity, durability, and safety of an mRNA vaccine candidate (RQ3013) and three other platform vaccines (an adenovirus-vectored vaccine candidate [ChAdTS-S], a recombinant protein vaccine candidate [ZR202-CoV], and an inactivated vaccine [CoronaVac]) as a booster. 250 eligible volunteers, who had received a prime two-dose CoronaVac (3 to 5 weeks apart) vaccination 100-270 days before, were randomly assigned in a 1:1:1:1:1 ratio to receive a third dose of RQ3013 (30 µg mRNA per 0.15 mL), ChAdTS-S (5×1010 viral particles per 0.5 mL), ZR202-CoV (25 µg prefusion-stabilized Spike ectodomain trimer per 0.5 mL), CoronaVac (3 µg inactivated CN02 strain of SARS-CoV-2 per 0.5 mL) or placebo (0.5 mL of 0.9% sodium chloride solution) via intramuscular injection into the upper arm at a single clinical site in Kunming, China. Participants, investigators, and immunogenicity laboratory were masked to group assignment. The primary immunogenicity outcomes were geometric mean titres (GMTs) of neutralising antibodies against live SARS-CoV-2 (wild-type, delta and omicron) virus at day 0 (before vaccination), day 7, day 14 and day 28 after vaccination, as analysed in a modified intention-to-treat (mITT) population (all participants who completed their booster doses and had at least one post-dose immunogenicity data). Secondary outcomes include T cell responses against the wild-type and omicron SARS-CoV-2 Spike protein. The primary safety outcome was incidence of adverse events within 14 days after the booster vaccination. This trial is registered with ChiCTR.org.cn, ChiCTR2200057758. Findings: Between January 1, 2022, and February 28, 2022, 235 eligible participants were enrolled and vaccinated, and the primary analysis included 234 participants. At baseline, neutralising antibodies against wild-type virus, the delta, or omicron variants were low or undetectable in all groups. After the booster vaccination, GMTs of neutralising antibodies ranged from 75.4 (95% confidence interval [CI] 61.4-92.5) in CoronaVac to 950.1 (95% CI 785.4-1149.3) in RQ3013 against live wild-type SARS-CoV-2, and from 8.1 (95% CI: 6.1-10.7) in CoronaVac to 247.0 (95% CI 194.1-314.3) in RQ3013 against the omicron variant at day 14. Immunogenicities of all heterologous regimens were superior to that of homologous regimen in neutralisation against all tested SARS-CoV-2 strains, with RQ3013 showing the highest geometric mean ratios (GMRs) of 12.6, 14.7, and 31.3 against the wild-type, the delta variant and the omicron variant compared to CoronaVac at day 14 post-vaccination, respectively. Durability analysis at day 90 showed that >90% of participants in RQ3013 and ZR202-CoV were seropositive for the omicron variant while ZR202-CoV with adjuvants containing CpG showed a slightly better durability than RQ3013. T cell responses specific to the omicron variant were similar to that of the wild-type, with RQ3013 showing the highest boosting effect. Any solicited injection site or systemic adverse events reported within 14 days after vaccination were most commonly observed in RQ3013 (47/47, 100%), followed by ZR202-CoV (46/47, 97.9%) and ChAdTS-S (43/48, 89.6%), and then CoronaVac (37/46, 80.4%) and placebo (21/47, 44.7%). More than 90% of the adverse events were grade 1 (mild) or 2 (moderate) with a typical resolution time of 3 days. No grade 4 adverse events or serious adverse events were reported by study vaccines. Interpretation: Although all study vaccines boosted neutralising antibodies with no safety concerns, RQ3013 showed much stronger cross-neutralisation and cellular responses, adding more effective vaccine candidates against the omicron variant. Funding: Yunnan Provincial Science and Technology Department China (202102AA100051 and 202003AC100010), the Double First-class University funding to Yunnan University, National Natural Science Foundation of China (81960116, 82060368 and 82170711), Yunnan Natural Science Foundation (202001AT070085), High-level Health Technical Personnel Project of Yunnan Province (H-2018102) and Spring City Plan: The High-level Talent Promotion and Training Project of Kunming.
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With the growth of population and industrialization of societies, the need for energy has increased. Due to the limited resources of non-renewable energy and the creation of various types of pollution, they should be replaced. Nowadays, renewable energy systems have been considered due to their compatibility with the environment. Polymer electrolyte fuel cells (PEMFCs) are an example of the use of renewable energy systems. PEMFCs, along with all their advantages, face the challenge of durability. The Snowball effect is a phenomenon that is followed by continuous reactions that reduce the durability of PEMFCs. The cause of this effect is the existence of various heterogeneities in fuel cells, which are controlled by water management through the current management strategy. On the other hand, efficient content training is valuable and necessary because it leads to a better understanding and, ultimately, progress in the field of fuel cells. With the spread of the Coronavirus and the virtualization of education, the need for change and diversity in education became more and more felt. Also, with the advancement of technology, it is better to use all available facilities to improve education. In this article, the effect of snowball and its solution has been easily taught by using new educational methods and visual s. © 2022 IEEE.
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Severe acute respiratory syndrome coronavirus 2 (COVID)-19 has emerged as the greatest global health threat in generations. An unprecedented mobilization of researchers has generated a wealth of data on humoral responses to SARS-CoV-2 within a year of the pandemic's beginning. The rapidly developed understanding of acute-phase antibody induction and medium-term antibody durability in COVID-19 is important at an individual level to inform patient care and a population level to help predict transmission dynamics. In this brief review, we will describe the development and maintenance of antibody responses to immunization and infections generally and the specific antibody dynamics observed for COVID-19. These crucial features of the humoral response have implications for the use of antibody therapeutics against the virus and can inform the likelihood of reinfection of individuals by the virus.
Subject(s)
COVID-19 , Antibodies, Viral , Humans , Immunoglobulin A , Immunoglobulin G , Immunoglobulin M , SARS-CoV-2ABSTRACT
The durability of immune responses after COVID-19 vaccination will drive long-term vaccine effectiveness across settings and may differ by vaccine type. To determine durability of protection of COVID-19 vaccines (BNT162b2, mRNA-1273, and Ad26.COV2.S) following primary vaccination in the United States, a matched case-control study was conducted in three cohorts between 1 January and 7 September 2021 using de-identified data from a database covering 168 million lives. Odds ratios (ORs) for developing outcomes of interest (breakthrough SARS-CoV-2 infection, hospitalization, or intensive care unit admission) were determined for each vaccine (no direct comparisons). In total, 17,017,435 individuals were identified. Relative to the baseline, stable protection was observed for Ad26.COV2.S against infections (OR [95% confidence interval (CI)], 1.31 [1.18-1.47]) and hospitalizations (OR [95% CI], 1.25 [0.86-1.80]). Relative to the baseline, protection waned over time against infections for BNT162b2 (OR [95% CI], 2.20 [2.01-2.40]) and mRNA-1273 (OR [95% CI], 2.07 [1.87-2.29]) and against hospitalizations for BNT162b2 (OR [95% CI], 2.38 [1.79-3.17]). Baseline protection remained stable for intensive care unit admissions for all three vaccines. Calculated baseline VE was consistent with published literature. This study suggests that the three vaccines in three separate populations may have different durability profiles.
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BACKGROUND: Vaccines have emerged as a crucial tool in combatting the COVID-19 pandemic particularly those based on SARS-CoV-2 S-protein mRNA. A crucial aspect of vaccine efficacy is the duration of antibody responses. In this study, a seroconversion panel was created to assess antibody responses to the mRNA-1273 vaccine over time (6.5 months). METHODS: Blood samples collected from 15 healthy adult participants prior to and up to 6.5 months after vaccination with the mRNA-1273 vaccine (Moderna). Serum from these blood samples were analyzed for anti-SARS-CoV-2 antibody activity by chemiluminescent immunoassay. RESULTS: The immunoassay results showed that one participant was positive for anti-SARS-CoV-2 antibodies prior to vaccination indicating a prior infection. All participants showed a positive antibody response after the first vaccination. Highest antibody responses were seen after the second dose (41-45 days from the first dose). Subsequent samples collected at 69-75 days, 130-135 days, and 221-229 days after the first vaccination showed positive responses but a biphasic decline in the levels of anti-SARS-CoV-2 antibodies. CONCLUSIONS: Declining antibody levels in these participants support the use of booster vaccination to increase antibody levels 4-6 months after the initial vaccine series and continued monitoring to assess the durability of COVID-19 vaccine responses. These results are in agreement with other studies showing antibody persistence but declining the antibody levels in the months after immunization with mRNA-based vaccines. The seroconversion panels described here could be useful in the development of antibody assays and in the assessment of the duration of antibody responses to vaccine boosters compared to the initial vaccine series. This panel could also be used to assess antibody activity against emerging viral variants (eg B.1.1.529 [Omicron] and its subvariants) compared to earlier variants. [ FROM AUTHOR] Copyright of Plasmatology is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)