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1.
Front Microbiol ; 13: 828806, 2022.
Article in English | MEDLINE | ID: covidwho-1793005

ABSTRACT

The coronavirus disease 2019 (COVID-19) vaccines have very successfully decreased the disease risk as we know; some key information remains unknown due to the short development history and the lack of long-term follow-up studies in vaccinated populations. One of the unanswered issues is the protection duration conferred after COVID-19 vaccination, which appears to play a pivotal role in the future impact of pathogens and is critical to inform the public health response and policy decisions. Here, we review current information on the long-term effectiveness of different COVID-19 vaccines, persistence of immunogenicity, and gaps in knowledge. Meanwhile, we also discuss the influencing factors and future study prospects on this topic.

2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-331783

ABSTRACT

Inflammation is a complex physiological process triggered in response to harmful stimuli. It involves specialized cells of the immune system able to clear sources of cell injury and damaged tissues to promote repair. Excessive inflammation can occur as a result of infections and is a hallmark of several diseases. The molecular basis underlying inflammatory responses are not fully understood. Here, we show that the cell surface marker CD44, which characterizes activated immune cells, acts as a metal transporter that promotes copper uptake. We identified a chemically reactive pool of copper(II) in mitochondria of inflammatory macrophages that catalyzes NAD(H) redox cycling by activating hydrogen peroxide. Maintenance of NAD + enables metabolic and epigenetic programming towards the inflammatory state. Targeting mitochondrial copper(II) with a rationally-designed dimer of metformin triggers distinct metabolic and epigenetic states that oppose macrophage activation. This drug reduces inflammation in mouse models of bacterial and viral (SARS-CoV-2) infections, improves well-being and increases survival. Identifying mechanisms that regulate the plasticity of immune cells provides the means to develop next-generation medicine. Our work illuminates the central role of copper as a regulator of cell plasticity and unveils a new therapeutic strategy based on metabolic reprogramming and the control of epigenetic cell states.

3.
Emerg Microbes Infect ; 11(1): 793-803, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1758587

ABSTRACT

The specific antibodies induced by SARS-CoV-2 infection may provide protection against a subsequent infection. However, the efficacy and duration of protection provided by naturally acquired immunity against subsequent SARS-CoV-2 infection remain controversial. We systematically searched for the literature describing COVID-19 reinfection published before 07 February 2022. The outcomes were the pooled incidence rate ratio (IRR) for estimating the risk of subsequent infection. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies. Statistical analyses were conducted using the R programming language 4.0.2. We identified 19 eligible studies including more than 3.5 million individuals without the history of COVID-19 vaccination. The efficacy of naturally acquired antibodies against reinfection was estimated at 84% (pooled IRR = 0.16, 95% CI: 0.14-0.18), with higher efficacy against symptomatic COVID-19 cases (pooled IRR = 0.09, 95% CI = 0.07-0.12) than asymptomatic infection (pooled IRR = 0.28, 95% CI = 0.14-0.54). In the subgroup analyses, the pooled IRRs of COVID-19 infection in health care workers (HCWs) and the general population were 0.22 (95% CI = 0.16-0.31) and 0.14 (95% CI = 0.12-0.17), respectively, with a significant difference (P = 0.02), and those in older (over 60 years) and younger (under 60 years) populations were 0.26 (95% CI = 0.15-0.48) and 0.16 (95% CI = 0.14-0.19), respectively. The risk of subsequent infection in the seropositive population appeared to increase slowly over time. In conclusion, naturally acquired antibodies against SARS-CoV-2 can significantly reduce the risk of subsequent infection, with a protection efficacy of 84%.Registration number: CRD42021286222.


Subject(s)
COVID-19 , Aged , Asymptomatic Infections , COVID-19/prevention & control , COVID-19 Vaccines , Health Personnel , Humans , SARS-CoV-2
4.
Frontiers in microbiology ; 13, 2022.
Article in English | EuropePMC | ID: covidwho-1733475

ABSTRACT

The coronavirus disease 2019 (COVID-19) vaccines have very successfully decreased the disease risk as we know;some key information remains unknown due to the short development history and the lack of long-term follow-up studies in vaccinated populations. One of the unanswered issues is the protection duration conferred after COVID-19 vaccination, which appears to play a pivotal role in the future impact of pathogens and is critical to inform the public health response and policy decisions. Here, we review current information on the long-term effectiveness of different COVID-19 vaccines, persistence of immunogenicity, and gaps in knowledge. Meanwhile, we also discuss the influencing factors and future study prospects on this topic.

5.
Asian Journal of Social Psychology ; : 1, 2022.
Article in English | Academic Search Complete | ID: covidwho-1714108

ABSTRACT

As the coronavirus disease 2019 (COVID‐19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), continues to rage, disclosure of exposure to the virus is of great significance to safety management, especially considering the long latency of the disease. We conducted a survey based on terror management theory of 2,542 people in 71 cities, representing all provinces in mainland China. The results revealed that fear of being isolated influenced disclosure of exposure to the virus and that this influence was mediated by defensive impression management motivation. An inclusive climate buffered both the direct and the indirect effects of fear of isolation on disclosure behaviour via defensive impression management motivation. The implications of these findings for research and safety management during the COVID‐19 pandemic are discussed. [ FROM AUTHOR] Copyright of Asian Journal of Social Psychology is the property of Wiley-Blackwell 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.)

6.
Clin Infect Dis ; 2021 Aug 14.
Article in English | MEDLINE | ID: covidwho-1704207

ABSTRACT

BACKGROUND: Follow-up study of Coronavirus disease 2019 (COVID-19) survivors has rarely been reported. We aimed to investigate longitudinal changes in the characteristics of COVID-19 survivors after discharge. METHODS AND FINDINGS: A total of 594 COVID-19 survivors discharged from Tongji Hospital in Wuhan from February 10 to April 30, 2020 were included and followed up until May 17, 2021. Laboratory and radiological findings, pulmonary function tests, electrocardiogram, symptoms and signs were analyzed. 257 (51.2%) patients had at least one symptom at 3 months post-discharge, which decreased to 169 (40.0%) and 138 (28.4%) at 6-month and 12-month visit respectively. During follow-up period, insomnia, chest tightness, and fatigue were the most prevalent symptoms. Most laboratory parameters returned to normal, whereas increased incidence of abnormal liver and renal function and cardiovascular injury was evidenced after discharge. Fibrous stripes (213; 42.4%), pleural thickening and adhesions (188; 37.5%) and enlarged lymph nodes (120; 23.9%) were the most common radiographical findings at 3 months post-discharge. The abnormalities of pulmonary function included obstructive, restrictive, and mixed, which were 5.5%, 4.0%, 0.9% at 6 months post, and 1.9%, 4.7%, 0.2% at 12 months. Electrocardiogram abnormalities occurred in 256 (51.0%) patients at 3 months post-discharge, including arrhythmia, ST-T change and conduction block, which increased to 258 (61.1%) cases at 6-month visit and were maintained at high frequency (242;49.8%) at 12-month visit. CONCLUSIONS: Physiological, laboratory, radiological or electrocardiogram abnormalities, particularly those related to renal, cardiovascular, liver functions are common in patients who recovered from COVID-19 up to 12months post-discharge.

7.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315629

ABSTRACT

Background: Novel coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-caused emerging infectious disease, firstly identified in Wuhan (Hubei, China), is pandemic. However, data concerning presymptomatic SARS-CoV-2 transmission and disease diversity among family members are limited. Objectives To investigate the epidemiological and clinical characteristics of presymptomatic transmission-caused familial clustering cases of SARS-CoV-2 infection in Zhoushan island, China. Methods All family members were tested for SARS-CoV-2 genomic RNA by quantitative reverse transcription PCR in 3 different samples and serum antibody immunoglobin M (IgM) and IgG against SARS-CoV-2. Exposure identification, laboratory test, and imaging were performed according to the national guideline of COVID-19 (7th edition, China). Results Of the 6 cases, index case who ever met his relative with COVID-19 from Xianning, Hubei on January 26–31, 2020, transmitted SARS-CoV-2 to his family members in Zhoushan via visiting family during January 31 and February 3, 2020. The index was identified as common-type COVID-19 on February 6, 2020. All 5 family members were infected with SARS-CoV-2. Of those, a 7-year-old girl was an asymptomatic carrier whereas her grandparents, especially her grandfather, were very sick. Case 6 (grandfather) remained positive for SARS-CoV-2 RNA in his sputum specimen in subsequent 2 months. Case 2 (mother) tested negative for SARS-CoV-2 RNA in all samples but positive for IgM and IgG to SARS-CoV-2 since February 9, 2020. Conclusions Presymptomatic transmission of SARS-CoV-2 causes familial cluster of COVID-19. Exposed to the same source of infection, family members present their differences in disease severity and viral clearance.

8.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315377

ABSTRACT

The dispersion of viral droplets plays a key role in the transmission of COVID-19. In this work, we analyze the dispersion of cough-generated droplets in the wake of a walking person for different space sizes. The air flow is simulated by solving the Reynolds-Averaged Navier-Stokes equations, and the droplets are modelled as passive Lagrangian particles. Simulation results show that the cloud of droplets locates around and below the waist height of the manikin after two seconds from coughing, which indicates that kids walking behind an infectious patient are exposed to higher transmission risk than adults. More importantly, two distinct droplet dispersion modes occupying significantly different contamination regions are discovered. A slight change of space size is found being able to trigger the transition of dispersion modes even though the flow patterns are still similar. This shows the importance of accurately simulating the air flow in predicting the dispersion of viral droplets and implies the necessity to set different safe-distancing guidelines for different environments.

9.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327136

ABSTRACT

The widespread SARS-CoV-2 in humans results in the continuous emergence of new variants. Recently emerged Omicron variant with multiple spike mutations sharply increases the risk of breakthrough infection or reinfection, highlighting the urgent need for new vaccines with broad-spectrum antigenic coverage. Using inter-lineage chimera and mutation patch strategies, we engineered a recombinant monomeric spike variant (STFK1628x), which showed high immunogenicity and mutually complementary antigenicity to its prototypic form (STFK). In hamsters, a bivalent vaccine comprised of STFK and STFK1628x elicited high titers of broad-spectrum antibodies to neutralize all 14 circulating SARS-CoV-2 variants, including Omicron;and fully protected vaccinees from intranasal SARS-CoV-2 challenges of either the ancestral strain or immune-evasive Beta variant. Strikingly, the vaccination of hamsters with the bivalent vaccine completely blocked the within-cage virus transmission to unvaccinated sentinels, for either the ancestral SARS-CoV-2 or Beta variant. Thus, our study provides new insights and antigen candidates for developing next-generation COVID-19 vaccines.

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-292884

ABSTRACT

Remarkable progress has been made in developing intramuscular vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2);however, they are limited with respect to eliciting local immunity in the respiratory tract, which is the primary infection site for SARS-CoV-2. To overcome the limitations of intramuscular vaccines, we constructed a nasal vaccine candidate based on an influenza vector by inserting a gene encoding the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, named CA4-dNS1-nCoV-RBD (dNS1-RBD). A preclinical study showed that in hamsters challenged 1 day and 7 days after single-dose vaccination or 6 months after booster vaccination, dNS1-RBD largely mitigated lung pathology, with no loss of body weight, caused by either the prototype-like strain or beta variant of SARS-CoV-2. Lasted data showed that the animals could be well protected against beta variant challenge 9 months after vaccination. Notably, the weight loss and lung pathological changes of hamsters could still be significantly reduced when the hamster was vaccinated 24 h after challenge. Moreover, such cellular immunity is relatively unimpaired for the most concerning SARS-CoV-2 variants. The protective immune mechanism of dNS1-RBD could be attributed to the innate immune response in the nasal epithelium, local RBD-specific T cell response in the lung, and RBD-specific IgA and IgG response. Thus, this study demonstrates that the intranasally delivered dNS1-RBD vaccine candidate may offer an important addition to fight against the ongoing COVID-19 pandemic, compensating limitations of current intramuscular vaccines, particularly at the start of an outbreak.

11.
Emerg Microbes Infect ; 10(1): 365-375, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1490458

ABSTRACT

Concerns about vaccine safety are an important reason for vaccine hesitancy, however, limited information is available on whether common adverse reactions following vaccination affect the immune response. Data from three clinical trials of recombinant vaccines were used in this post hoc analysis to assess the correlation between inflammation-related solicited adverse reactions (ISARs, including local pain, redness, swelling or induration and systematic fever) and immune responses after vaccination. In the phase III trial of the bivalent HPV-16/18 vaccine (Cecolin®), the geometric mean concentrations (GMCs) for IgG anti-HPV-16 and -18 (P<0.001) were significantly higher in participants with any ISAR following vaccination than in those without an ISAR. Local pain, induration, swelling and systemic fever were significantly correlated with higher GMCs for IgG anti-HPV-16 and/or anti-HPV-18, respectively. Furthermore, the analyses of the immunogenicity bridging study of Cecolin® and the phase III trial of a hepatitis E vaccine yielded similar results. Based on these results, we built a scoring model to quantify the inflammation reactions and found that the high score of ISAR indicates the strong vaccine-induced antibody level. In conclusion, this study suggests inflammation-related adverse reactions following vaccination potentially indicate a stronger immune response.


Subject(s)
Hepatitis E/immunology , Human papillomavirus 16/immunology , Human papillomavirus 18/immunology , Papillomavirus Infections/immunology , Papillomavirus Vaccines/immunology , Vaccines, Synthetic/immunology , Viral Hepatitis Vaccines/immunology , Adolescent , Adult , Aged , Antibodies, Viral/immunology , Female , Hepatitis E/prevention & control , Hepatitis E/virology , Human papillomavirus 16/genetics , Human papillomavirus 18/genetics , Humans , Immunity , Immunoglobulin G/immunology , Male , Middle Aged , Papillomavirus Infections/prevention & control , Papillomavirus Infections/virology , Papillomavirus Vaccines/administration & dosage , Papillomavirus Vaccines/adverse effects , Papillomavirus Vaccines/genetics , Vaccination/adverse effects , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/adverse effects , Vaccines, Synthetic/genetics , Viral Hepatitis Vaccines/administration & dosage , Viral Hepatitis Vaccines/adverse effects , Viral Hepatitis Vaccines/genetics , Young Adult
12.
Biomed J ; 44(6S1): S8-S14, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1482465

ABSTRACT

BACKGROUND: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) is highly contagious, with a potential to cause large nosocomial outbreaks in the hospital setting. We report the advance deployment of comprehensive, multi-level infection control measures in a 3,700-bed large hospital to prevent nosocomial outbreaks of COVID-19 during the pandemic. METHODS: We implemented a series of dynamic infection control policies during the pandemic. A confirmed COVID-19 case was defined by positive real-time reverse transcriptase-polymerase chain reaction (RT-PCR) assay. All healthcare worker (HCW) having symptoms or close contact with the confirmed case received the RT-PCR test. RESULTS: A total of 5,722 patients were tested in our hospital from January to May 2020. Twenty-five patients were confirmed COVID-19, including two inpatients. A cluster of 4 HCWs with COVID-19 associated with the 2nd inpatient was identified in the early stage of epidemic. Our enhanced traffic control bundling, mask wearing, hand hygiene and environmental cleaning were reinforced after the outbreak. All other confirmed cases were identified at our outdoor quarantine station or epidemic clinic afterwards, and the results of testing for 146 symptomatic HCWs were all negative. CONCLUSIONS: Integrated teamwork, advance deployment of infection control measures and efficient diagnostic testing and response protected HCW and facilities from large SARS-CoV-2 outbreaks and preserved the capacity and function of the health care system during the pandemic.


Subject(s)
COVID-19 , Cross Infection , COVID-19/epidemiology , Cross Infection/prevention & control , Disease Outbreaks/prevention & control , Hospitals , Humans , Infection Control/methods , Pandemics/prevention & control , SARS-CoV-2 , Taiwan/epidemiology
13.
J Hazard Mater ; 423(Pt B): 127144, 2022 02 05.
Article in English | MEDLINE | ID: covidwho-1433515

ABSTRACT

During coronavirus disease 2019 pandemic, the exponential increase in clinical waste (CW) generation has caused immense burden to CW treatment facilities. Co-incineration of CW in municipal solid waste incinerator (MSWI) is an emergency treatment method. A material flow model was developed to estimate the change in feedstock characteristics and resulting acid gas emission under different CW co-incineration ratios. The ash contents and lower heating values of the feedstocks, as well as HCl concentrations in flue gas showed an upward trend. Subsequently, 72 incineration residue samples were collected from a MSWI performing co-incineration (CW ratio <10 wt%) in Wuhan city, China, followed by 20 incineration residues samples from waste that were not co-incineration. The results showed that the contents of major elements and non-volatile heavy metals in the air pollution control residues increased during co-incineration but were within the reported ranges, whereas those in the bottom ashes revealed no significant changes. The impact of CW co-incineration at a ratio <10 wt% on the distribution of elements in the incineration residues was not significant. However, increase in alkali metals and HCl in flue gas may cause potential boiler corrosion. These results provide valuable insights into pollution control in MSWI during pandemic.


Subject(s)
COVID-19 , Metals, Heavy , Refuse Disposal , Coal Ash , Humans , Incineration , Pandemics , SARS-CoV-2 , Solid Waste/analysis
14.
Chinese Journal of Virology ; 36(4):541-548, 2020.
Article in Chinese | GIM | ID: covidwho-1407614

ABSTRACT

To date, the coronavirus disease 2019 (COVID-19) pandemic is impacting globally. COVID-19 is mainly diagnosed via viral nucleic acid testing, but with the disadvantages of unsatisfactory sensitivity and high requirements for expensive equipment and facility the operating settings. Compared with nucleic acid testing, antibody testing usually has advantages as wide popularization, convenient sample collection, easy to achieve high throughput. less workload, high reproducibility, and low cost, therefore it will be an efficient supplement for nucleic acid detection to confirm COVID-19. This protocol provided detailed design for the assessment of antibody testing reagent, including consideration for the study objectives, calculation of sample size, inclusion and exclusion criteria, blinding method, experimental specimen, ethical issues, study management and quality control, data management and statistical analysis. and results report and so on, aiming to assist the researchers to systematically assess the critical performance of antibody testing reagent prior to large-scale application of the antibody testing reagent, so that researchers could make reasonable choices among different antibody testing reagents according to their respective purposes.

15.
Clin Infect Dis ; 2021 Aug 14.
Article in English | MEDLINE | ID: covidwho-1356658

ABSTRACT

BACKGROUND: Follow-up study of Coronavirus disease 2019 (COVID-19) survivors has rarely been reported. We aimed to investigate longitudinal changes in the characteristics of COVID-19 survivors after discharge. METHODS AND FINDINGS: A total of 594 COVID-19 survivors discharged from Tongji Hospital in Wuhan from February 10 to April 30, 2020 were included and followed up until May 17, 2021. Laboratory and radiological findings, pulmonary function tests, electrocardiogram, symptoms and signs were analyzed. 257 (51.2%) patients had at least one symptom at 3 months post-discharge, which decreased to 169 (40.0%) and 138 (28.4%) at 6-month and 12-month visit respectively. During follow-up period, insomnia, chest tightness, and fatigue were the most prevalent symptoms. Most laboratory parameters returned to normal, whereas increased incidence of abnormal liver and renal function and cardiovascular injury was evidenced after discharge. Fibrous stripes (213; 42.4%), pleural thickening and adhesions (188; 37.5%) and enlarged lymph nodes (120; 23.9%) were the most common radiographical findings at 3 months post-discharge. The abnormalities of pulmonary function included obstructive, restrictive, and mixed, which were 5.5%, 4.0%, 0.9% at 6 months post, and 1.9%, 4.7%, 0.2% at 12 months. Electrocardiogram abnormalities occurred in 256 (51.0%) patients at 3 months post-discharge, including arrhythmia, ST-T change and conduction block, which increased to 258 (61.1%) cases at 6-month visit and were maintained at high frequency (242;49.8%) at 12-month visit. CONCLUSIONS: Physiological, laboratory, radiological or electrocardiogram abnormalities, particularly those related to renal, cardiovascular, liver functions are common in patients who recovered from COVID-19 up to 12months post-discharge.

16.
Sensors (Basel) ; 21(15)2021 Aug 01.
Article in English | MEDLINE | ID: covidwho-1346533

ABSTRACT

Due to the COVID-19 virus being highly transmittable, frequently cleaning and disinfecting facilities is common guidance in public places. However, the more often the environment is cleaned, the higher the risk of cleaning staff getting infected. Therefore, strong demand for sanitizing areas in automatic modes is undoubtedly expected. In this paper, an autonomous disinfection vehicle with an Ultraviolet-C (UVC) lamp is designed and implemented using an ultra-wideband (UWB) positioning sensor. The UVC dose for 90% inactivation of the reproductive ability of COVID-19 is 41.7 J/m2, which a 40 W UVC lamp can achieve within a 1.6 m distance for an exposure time of 30 s. With this UVC lamp, the disinfection vehicle can effectively sterilize in various scenarios. In addition, the high-accuracy UWB positioning system, with the time difference of arrival (TDOA) algorithm, is also studied for autonomous vehicle navigation in indoor environments. The number of UWB tags that use a synchronization protocol between UWB anchors can be unlimited. Moreover, this proposed Gradient Descent (GD), which uses Taylor method, is a high-efficient algorithm for finding the optimal position for real-time computation due to its low error and short calculating time. The generalized traversal path planning procedure, with the edge searching method, is presented to improve the efficiency of autonomous navigation. The average error of the practical navigation demonstrated in the meeting room is 0.10 m. The scalability of the designed system to different application scenarios is also discussed and experimentally demonstrated. Hence, the usefulness of the proposed UWB sensor applied to UVC disinfection vehicles to prevent COVID-19 infection is verified by employing it to sterilize indoor environments without human operation.


Subject(s)
COVID-19 , Disinfection , Algorithms , Humans , Research Design , SARS-CoV-2
17.
J Microbiol Immunol Infect ; 2021 Jul 21.
Article in English | MEDLINE | ID: covidwho-1336662

ABSTRACT

BACKGROUND/PURPOSE: Superspreading events (SSEs) are pivotal in the spread of SARS-CoV-2. This study aimed to investigate an SSE of COVID-19 in a hospital and explore the transmission dynamics and heterogeneity of SSE. METHODS: We performed contact tracing for all close contacts in a cluster. We did nasopharyngeal or throat swabbing for SARS-CoV-2 by real-time RT-PCR. Environmental survey was performed. The epidemiological and clinical characteristics of the SSE were studied. RESULTS: Patient 1 with congestive heart failure and cellulitis, who had onset of COVID-19 two weeks after hospitalization, was the index case. Patient 1 led to 8 confirmed cases, including four health care workers (HCW). Persons tested positive for SARS-CoV-2 were HCW (n = 4), patient 1's family (n = 2), an accompanying person of an un-infected in-patient (n = 1), and an in-patient admitted before the SSE (n = 1). The attack rate among the HCW was 3.2 % (4/127). Environmental survey confirmed contamination at the bed rails, mattresses, and sink in the room patient 1 stayed, suggesting fomite transmission. The index case's sputum remained positive on illness day 35. Except one asymptomatic patient, at least three patients acquired the infection from the index case at the pre-symptomatic period. The effective reproduction number (Rt) was 0.9 (8/9). CONCLUSION: The host factor (heart failure, longer viral shedding), transmissibility of SARS-CoV-2 (Rt, pre-symptomatic transmission), and possible multiple modes of transmission altogether contributed to the SSE. Rapid response and advance deployment of multi-level protection in hospitals could mitigate COVID-19 transmission to one generation, thereby reducing its impact on the healthcare system.

18.
BMJ Support Palliat Care ; 2021 Jul 30.
Article in English | MEDLINE | ID: covidwho-1334588

ABSTRACT

A novel coronavirus first discovered in late December 2019 has spread to many countries around the world. An increasing number of asymptomatic patients have been reported and their ability to spread the virus has been proven. This brings major challenges to the control of the transmission. The discovery and control of asymptomatic patients with COVID-19 are the key issues in future epidemic prevention and recovery. In this narrative review, we summarise the existing knowledge about asymptomatic patients and put forward detection methods that are suitable for finding such patients. Besides, we compared the characteristics and transmissibility of asymptomatic patients in different populations in order to find the best screening, diagnosis and control measures for different populations. Comprehensive preventive advice is also provided to prevent the spread of infection from asymptomatic patients.

20.
Front Med (Lausanne) ; 8: 702066, 2021.
Article in English | MEDLINE | ID: covidwho-1323082

ABSTRACT

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to public concern worldwide. Although a variety of hypotheses about the hosts of SARS-CoV-2 have been proposed, an exact conclusion has not yet been reached. Initial clinical manifestations associated with COVID-19 are similar to those of other acute respiratory infections, leading to misdiagnoses and resulting in the outbreak at the early stage. SARS-CoV-2 is predominantly spread by droplet transmission and close contact; the possibilities of fecal-oral, vertical, and aerosol transmission have not yet been fully confirmed or rejected. Besides, COVID-19 cases have been reported within communities, households, and nosocomial settings through contact with confirmed COVID-19 patients or asymptomatic individuals. Environmental contamination is also a major driver for the COVID-19 pandemic. Considering the absence of specific treatment for COVID-19, it is urgent to decrease the risk of transmission and take preventive measures to control the spread of the virus. In this review, we summarize the latest available data on the potential hosts, entry receptors, clinical features, and risk factors of COVID-19 and transmission routes of SARS-CoV-2, and we present the data about development of vaccines.

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