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1.
Disease Surveillance ; 37(1):72-76, 2022.
Article in Chinese | GIM | ID: covidwho-1789475

ABSTRACT

Objective: To understand the change characteristics of respiratory pathogens in hospitalized children with respiratory tract infection in Shunyi district of Beijing from 2019 to 2020, and to provide basis for the prevention and treatment of respiratory tract diseases in children.

2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-331665

ABSTRACT

: Objective To analyze the current status, hotspots and frontier trends of genomics research on the outbreak of novel coronavirus disease (COVID-19) from 2019 to the present (March 2022). Methods Using citespace software to conduct statistical and visual analysis of data in each country, institutions, authors, journals, co-cited literature, keywords, etc. were published on the 2019-2022 Web of Science Core Collection Database (WOS) on the genomics of novel coronavirus pneumonia Results of related literature. Results A total of 9,121 English literatures were included. In 2021, the number of publications has increased significantly, and it is expected to continue to show a continuous upward trend in the future. The research hotspots of COVID-19 revolve around quarantine, biological management, angiotensin-converting enzyme-2, rna-dependent rna polymerase, etc. Research fronts and trends focus on molecular docking, messenger RNA,functional receptor, etc. Conclusion The research attention in the field of novel coronavirus pneumonia genomics has increased significantly in the past two years.

4.
Appl Nanosci ; : 1-7, 2022 Feb 03.
Article in English | MEDLINE | ID: covidwho-1707936

ABSTRACT

The importance of ferritin as an inflammatory marker is well recognized. However, it is unknown whether this differs between Covid-19 and non-Covid-19 patients. The blood levels of ferritin, white blood cells (WBC), C-reactive protein (CRP), and lactate dehydrogenase may all be measured to check whether there is a difference. The researchers want to see if the inflammatory process changes between these two kinds (LDH). Methodology: Blood samples were collected from 119 COVID-19 patients in the hospital and 50 healthy persons. Corona virus was discovered when a nasopharyngeal swab was collected and tested using the RT-PCR technique. Ferritin, LDH, WBC, and CRP were also tested using Min Vidus, AccEnT 200, Ruby system, and Latx in that sequence. The study revealed that COVID-19 patients had higher levels of ferritin, WBC, CRP, and LDH in their blood than healthy people, with values of 539,08 ng/mL, 44.7109/L, 22.95 mg/L, and 403.95 U/L for COVID-19 patients versus 77.103 ng/mL, 4.9.4109/L, 6.53 mg/L, and 171.56 U/L for healthy people. According to the existing data, males are more likely to be infected with COVID-19 (81%) than females (32%), and females had greater ferritin, CRP, WBC, and LDH levels than males. Because they are related to an optimum test for predicting COVID-19 infection, the recommended cut-off values for ferritin, WBC, CRP, and LDH are 109.8 ng/mL, 14.9109/L, 10.15 mg/L, and 229.33 U/L, respectively. Finally, an increase in ferritin levels in the inflammatory response to COVID-19 is linked to an increase in inflammatory markers including CRP, WBC, and LDH, which may assist in the diagnosis of COVID-19 infection.

6.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-323932

ABSTRACT

Background: Patients with severe Coronavirus Disease 2019 (COVID-19) will progress rapidly to acute respiratory failure or death. We aimed to develop a quantitative tool for early predicting mortality risk of patients with COVID-19. Methods: : 301 patients with confirmed COVID-19 admitted to Main District and Tumor Center of the Union Hospital of Huazhong University of Science and Technology (Wuhan, China) between January 1, 2020 to February 15, 2020 were enrolled in this retrospective two-centers study. Data on patient demographic characteristics, laboratory findings and clinical outcomes was analyzed. A nomogram was constructed to predict the death probability of COVID-19 patients. Results: : Age, neutrophil-to-lymphocyte ratio, D-dimer and C-reactive protein obtained on admission were identified by LASSO regression as predictors of mortality for COVID-19 patients. The nomogram demonstrated good calibration and discrimination with the area under the curve (AUC) of 0.921 and 0.975 for the derivation and validation cohort, respectively. An integrated score (named ANDC) with its corresponding death probability was derived. Using ANDC cut-off values of 59 and 101, COVID-19 patients were classified into three subgroups. The death probability of low risk group (ANDC < 59) was less than 5%, moderate risk group (59 ≤ ANDC ≤ 101) was 5% to 50%, and high risk group (ANDC > 101) was more than 50%, respectively. Conclusion: The prognostic nomogram exhibited good discrimination power in early identification of COVID-19 patients with high mortality risk, and ANDC score may help physicians to optimize patient stratification management.

7.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-323804

ABSTRACT

The spread of the coronavirus disease 2019 (COVID-19) had resulted in 16 million infected individuals and 640000 deaths across the world as of July 27, 2020. Unfortunately, there is still no sign that the epidemic spread is slowing down. China, as the first country suffering from the widespread outbreak of the epidemic, has effectively contained the spread of the epidemic since March, 2020. Therefore, confirmed cases of COVID-19 from January 20 to March 18, 2020 were taken as the sample set to establish the susceptible-exposed-infected-recovered (SEIR) model. The model was used to analyze changes in the numbers of individuals becoming infected, exposed (latently infected), susceptible, and recovered in the experimental groups taking different non-pharmaceutical interventions (NPIs) and in the control group not taking any NPIs, so as to evaluate effects of different NPIs. By doing so, the research expects to provide references to other countries for formulating corresponding policies. The results show that type-A NPIs for reducing daily contacts with infected and exposed cases and type-B NPIs for decreasing the probability of post-exposure infections both can delay the timing of large-scale infections of the susceptible population, timing of the number of exposed individuals to peak, and timing of peaking of the number of infected cases, as well as decrease the peak number of exposed cases. Moreover, type-B NPIs have more significant effects on susceptible and exposed populations. Type-C NPIs for improving the recovery rate of patients are able to effectively reduce the peak number of patients, greatly decrease the slope of the curve for the number of infected cases, substantially improve the recovery rate, and lower the mortality rate;however, these NPIs do not greatly delay the timing of the number of infected cases to peak. In addition to these, considering effects of different NPIs on the susceptible and exposed populations and in delaying the timing for the number of infected cases to peak, it is found that the government’s organization of medical supply related companies to resume production exerts the best effect. As for reducing the epidemic number of patients in the core epidemic area (CEA, Hubei Province), delivery and putting-into-operation of Leishenshan hospital shows the best effect, followed by dispatching of medical staff to support Wuhan, delivery and putting-into-operation of Huoshenshan hospital, and construction of mobile cabin hospitals.

8.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-315379

ABSTRACT

Background: While the immunogenicity of inactivated vaccines against coronavirus disease 2019 (COVID‐19) has been characterized in several well-conducted clinical trials, real-world evidence concerning immune responses against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) raised by such vaccines is currently missing. Here, we comprehensively characterized various parameters of SARS-CoV-2-specific cellular and humoral immune responses induced by inactivated COVID-19 vaccines under real-world conditions. Methods: Venous blood was collected from 126 adults, before and/or after inactivated COVID-19 vaccine inoculation. SARS-CoV-2 neutralizing antibody (NAb) and S-receptor binding domain IgG in the serum were detected. The isolated peripheral blood mononuclear cells were stimulated by three pools of lyophilized peptides covering the spike, nucleocapsid, and membrane protein of SARS-CoV-2 for evaluating antigen-specific T cell responses against the virus. Findings: The seroconversion rate for S-RBD IgG and NAb after two doses of vaccination was 87.06% (74/85) and 78.82% (67/85), respectively. Female participants developed higher concentrations of S-RBD IgG and NAb compared to male vaccinees. Interestingly, a longer dosing interval between the first and second vaccination resulted in a better long-term SARS-CoV-2 S-RBD IgG response. The frequencies of CD4+ T cells that produce effector cytokines (IFN-γ, IL-2, and TNF-α) in response to stimulation with peptide pools corresponding to the SARS-CoV-2 spike (S), nucleocapsid (N) or membrane (M) protein increased significantly after a single vaccination dose, and continued to increase after the second administration. S, N, or M-specific CD4+ and CD8+ T cell responses became detectable in 95.83% (69/72) and 54.16% (39/72) of double-vaccinated individuals, respectively. The longitudinal analysis demonstrated that CD4+ T cell responses recognizing S, N, and M waned quickly after a single vaccine dose, but were boosted and became more sustained following a second dose. Interpretation: Both humoral and cellular SARS-CoV-2-specific immunity are elicited in the majority of individuals after two doses of inactivated COVID-19 vaccines. Trial Registration: Chinese Clinical Trial Registry (ChiCTR2100048837).Funding Fundamental Research Funds for the Central Universities, National Natural Science Foundation of China, National Science and Technology Major Project, Deutsche Forschungsgemeinschaft, Medical Faculty of the University of Duisburg-Essen and Stiftung Universiätsmedizin, University Hospital Essen, Germany, and the Tongji-Rongcheng Center for Biomedicine, Huazhong University of Science and Technology.Declaration of Interest: None to declare. Ethical Approval: The study protocol was approved by the local medical ethics committee of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (2021-0570)

9.
Int J Gen Med ; 15: 849-857, 2022.
Article in English | MEDLINE | ID: covidwho-1674134

ABSTRACT

Background: The role of the complement system in coronavirus disease 2019 (COVID-19) remains controversial. This study aimed to evaluate the relationship between serum complement C3 levels, clinical worsening, and risk of death in hospitalized patients with COVID-19. Methods: Data were collected from 216 adults with COVID-19 admitted to a designated clinical center in Wuhan Union Hospital (China) between February 13, 2020, and February 29, 2020. Their complement C3 levels were measured within 24 h of admission. The primary outcome was a clinical worsening of 2 points on a 6-point ordinal scale. The secondary outcome was all-causes of death. Inverse probability of treatment weighting (IPTW) analysis was conducted to adjust for the baseline confounders. Results: The median value of C3 was 0.89 (interquartile range, 0.78-1.01) g/L. Clinical worsening occurred in 12.3% (7/57) and 2.5% (4/159) of patients with baseline C3 levels < and ≥0.79 g/L, respectively (hazard ratio [HR], 5.22; 95% confidence interval [CI], 1.53-17.86). After IPTW adjustment, the risk for clinical worsening was 4-fold greater (weighted HR, 4.61; 95% CI, 1.16-18.4) in patients with C3 levels less than 0.79 g/L comparatively. The sensitivity analyses revealed the robustness of the results. No significant associations between C3 levels and death were observed on unadjusted (HR, 2.92; 95% CI, 0.73-11.69) and IPTW analyses (weighted HR, 3.78; 95% CI, 0.84-17.04). Conclusion: Low complement C3 levels are associated with a higher risk for clinical worsening among inpatients with COVID-19. The serum C3 levels may contribute to the identification of patient populations that could benefit from therapeutic complement inhibition.

10.
Frontiers in immunology ; 12, 2021.
Article in English | EuropePMC | ID: covidwho-1602189

ABSTRACT

While the immunogenicity of inactivated vaccines against coronavirus disease 2019 (COVID‐19) has been characterized in several well-conducted clinical trials, real-world evidence concerning immune responses against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) raised by such vaccines is currently missing. Here, we comprehensively characterized various parameters of SARS-CoV-2-specific cellular and humoral immune responses induced by inactivated COVID-19 vaccines in 126 individuals under real-world conditions. After two doses of vaccination, S-receptor binding domain IgG (S-RBD IgG) and neutralizing antibody (NAb) were detected in 87.06% (74/85) and 78.82% (67/85) of individuals, respectively. Female participants developed higher concentrations of S-RBD IgG and NAb compared to male vaccinees. Interestingly, a longer dosing interval between the first and second vaccination resulted in a better long-term SARS-CoV-2 S-RBD IgG response. The frequencies of CD4+ T cells that produce effector cytokines (IFN-γ, IL-2, and TNF-α) in response to stimulation with peptide pools corresponding to the SARS-CoV-2 spike (S), nucleocapsid (N) or membrane (M) protein were significantly higher in individuals received two doses of vaccine than those received one dose of vaccine and unvaccinated individuals. S, N, or M-specific CD4+ and CD8+ T cell responses were detectable in 95.83% (69/72) and 54.16% (39/72) of double-vaccinated individuals, respectively. The longitudinal analysis demonstrated that CD4+ T cell responses recognizing S, N, and M waned quickly after a single vaccine dose, but were boosted and became more sustained following a second dose. Overall, we provide a comprehensive characterization of immune responses induced by inactivated COVID-19 vaccines in real-world settings, suggesting that both humoral and cellular SARS-CoV-2-specific immunity are elicited in the majority of individuals after two doses of inactivated COVID-19 vaccines.

11.
Ann Med ; 53(1): 181-188, 2021 12.
Article in English | MEDLINE | ID: covidwho-1575964

ABSTRACT

OBJECTIVE: To illustrate the effect of corticosteroids and heparin, respectively, on coronavirus disease 2019 (COVID-19) patients' CD8+ T cells and D-dimer. METHODS: In this retrospective cohort study involving 866 participants diagnosed with COVID-19, patients were grouped by severity. Generalized additive models were established to explore the time-course association of representative parameters of coagulation, inflammation and immunity. Segmented regression was performed to examine the influence of corticosteroids and heparin upon CD8+ T cell and D-dimer, respectively. RESULTS: There were 541 moderate, 169 severe and 156 critically ill patients involved in the study. Synchronous changes of levels of NLR, D-dimer and CD8+ T cell in critically ill patients were observed. Administration of methylprednisolone before 14 DFS compared with those after 14 DFS (ß = 0.154%, 95% CI=(0, 0.302), p=.048) or a dose lower than 40 mg per day compared with those equals to 40 mg per day (ß = 0.163%, 95% CI=(0.027, 0.295), p=.020) significantly increased the rising rate of CD8+ T cell in 14-56 DFS. CONCLUSIONS: The parameters of coagulation, inflammation and immunity were longitudinally correlated, and an early low-dose corticosteroid treatment accelerated the regaining of CD8+ T cell to help battle against SARS-Cov-2 in critical cases of COVID-19.


Subject(s)
CD8-Positive T-Lymphocytes/drug effects , COVID-19/drug therapy , Glucocorticoids/administration & dosage , Inflammation/drug therapy , Adult , Aged , Aged, 80 and over , Blood Coagulation/drug effects , Blood Coagulation/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/blood , COVID-19/diagnosis , COVID-19/immunology , Dose-Response Relationship, Drug , Female , Fibrin Fibrinogen Degradation Products/analysis , Fibrin Fibrinogen Degradation Products/immunology , Heparin/administration & dosage , Humans , Inflammation/blood , Inflammation/diagnosis , Inflammation/immunology , Linear Models , Longitudinal Studies , Lymphocyte Count , Male , Methylprednisolone/administration & dosage , Middle Aged , Models, Biological , Retrospective Studies , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Severity of Illness Index , Time Factors , Time-to-Treatment , Young Adult
13.
Ocean Coast Manag ; 215: 105974, 2021 Dec 01.
Article in English | MEDLINE | ID: covidwho-1510162

ABSTRACT

The sudden outbreak of COVID-19 has led beach tourism to a complete halt in January 2020, disrupting millions of livelihoods and businesses. Due to the economic importance of beach tourism, many governments reopened tourist beaches after the number of confirmed cases decreased. It is essential to open beaches orderly to meet the needs of tourists, maintain beach's health and restore coastal economy under the new reality. This paper selected Qingdao in China as a case study, drew on a questionnaire survey among beach tourists, summarized the effects of the COVID-19 on beach tourism industry and tourism enterprise, analyzed beach tourists' psychology and behavior, and developed beach management strategy under the ongoing prevention and control of COVID-19. The results showed that the COVID-19 pandemic caused severe damage to beach tourism which bases on travel and mobility, and this industry was temporarily suspended. With the changing epidemic situation, beach tourism witnessed a gradual recovery from stagnation to local tourism. Meanwhile, tourism enterprises were hit by the devastating impact of the COVID-19, causing problems such as business reduction, tense cash flow, high operating cost and unclear market prospect. Under the normalization of pandemic prevention, tourists did not have severe fear and anxiety about the pandemic, and placed great importance on the prevention and control measures, emergency measures and pandemic risk level of the beach destination. The pandemic also reshaped the perception and mode of beach tourism. Ecological tourism, travelling with family, and local tourism became the primary choices for tourists. Beach congestion, health status, and the quality of tourism services were the biggest concerns for tourists. Additionally, social media and short video APP became the new marketing channels. Finally, beach management strategies were proposed from the aspects of pandemic prevention and control, emergency management, information communication, tourist management, service management, and environmental management.

14.
Food Funct ; 12(20): 9607-9619, 2021 Oct 19.
Article in English | MEDLINE | ID: covidwho-1500759

ABSTRACT

At the end of 2019, the COVID-19 virus spread worldwide, infecting millions of people. Infectious diseases induced by pathogenic microorganisms such as the influenza virus, hepatitis virus, and Mycobacterium tuberculosis are also a major threat to public health. The high mortality caused by infectious pathogenic microorganisms is due to their strong virulence, which leads to the excessive counterattack by the host immune system and severe inflammatory damage of the immune system. This paper reviews the efficacy, mechanism and related immune regulation of epigallocatechin-3-gallate (EGCG) as an anti-pathogenic microorganism drug. EGCG mainly shows both direct and indirect anti-infection effects. EGCG directly inhibits early infection by interfering with the adsorption on host cells, inhibiting virus replication and reducing bacterial biofilm formation and toxin release; EGCG indirectly inhibits infection by regulating immune inflammation and antioxidation. At the same time, we reviewed the bioavailability and safety of EGCG in vivo. At present, the bioavailability of EGCG can be improved to some extent using nanostructured drug delivery systems and molecular modification technology in combination with other drugs. This study provides a theoretical basis for the development of EGCG as an adjuvant drug for anti-pathogenic microorganisms.


Subject(s)
Anti-Infective Agents/pharmacology , Catechin/analogs & derivatives , Catechin/pharmacology , Immunologic Factors/pharmacology , Animals , Antioxidants/pharmacology , COVID-19/drug therapy , Coronavirus/drug effects , Hepatitis Viruses/drug effects , Humans , Inflammation/drug therapy , Mycobacterium tuberculosis/drug effects , Orthomyxoviridae/drug effects , Oxidative Stress/drug effects , SARS-CoV-2/drug effects , Virus Replication/drug effects
15.
Open Med (Wars) ; 16(1): 1403-1414, 2021.
Article in English | MEDLINE | ID: covidwho-1456126

ABSTRACT

There is no specific drug for coronavirus disease 2019 (COVID-19). We aimed to investigate the possible clinical efficacy of moderate-dose vitamin C infusion among inpatients with severe COVID-19. Data of 397 adult patients with severe COVID-19 admitted to a designated clinical center of Wuhan Union Hospital (China) between February 13 and February 29, 2020, were collected. Besides standard therapies, patients were treated with vitamin C (2-4 g/day) or not. The primary outcome was all-cause death. Secondary outcome was clinical improvement of 2 points on a 6-point ordinal scale. About 70 participants were treated with intravenous vitamin C, and 327 did not receive it. No significant association was found between vitamin C use and death on inverse probability treatment weighting (IPTW) analysis (weighted hazard ratio [HR], 2.69; 95% confidence interval [CI], 0.91-7.89). Clinical improvement occurred in 74.3% (52/70) of patients in the vitamin C group and 95.1% (311/327) in the no vitamin C group. No significant difference was observed between the two groups on IPTW analysis (weighted HR, 0.76; 95% CI, 0.55-1.07). Our findings revealed that in patients with severe COVID-19, treatment with moderate dose of intravenous vitamin C had no significant benefit on reducing the risk of death and obtaining clinical improvement.

16.
Sci Adv ; 7(38): eabb5933, 2021 Sep 17.
Article in English | MEDLINE | ID: covidwho-1440796

ABSTRACT

Growing evidence indicates the vital role of lipid metabolites in innate immunity. The lipid lysophosphatidic acid (LPA) concentrations are enhanced in patients upon HCV or SARS-CoV-2 infection, but the function of LPA and its receptors in innate immunity is largely unknown. Here, we found that viral infection promoted the G protein­coupled receptor LPA1 expression, and LPA restrained type I/III interferon production through LPA1. Mechanistically, LPA1 signaling activated ROCK1/2, which phosphorylated IRF3 Ser97 to suppress IRF3 activation. Targeting LPA1 or ROCK in macrophages, fibroblasts, epithelial cells, and LPA1 conditional KO mice promoted interferon-induced clearance of multiple viruses. LPA1 was colocalized with the receptor ACE2 in lung and intestine. Together with previous findings that LPA1 and ROCK1/2 promoted vascular leaking or lung fibrosis, we propose that the current available preclinical drugs targeting the LPA1-ROCK module might protect from SARS-CoV-2 or various virus infections in the intestine or lung.

17.
Food Funct ; 12(20): 9607-9619, 2021 Oct 19.
Article in English | MEDLINE | ID: covidwho-1434159

ABSTRACT

At the end of 2019, the COVID-19 virus spread worldwide, infecting millions of people. Infectious diseases induced by pathogenic microorganisms such as the influenza virus, hepatitis virus, and Mycobacterium tuberculosis are also a major threat to public health. The high mortality caused by infectious pathogenic microorganisms is due to their strong virulence, which leads to the excessive counterattack by the host immune system and severe inflammatory damage of the immune system. This paper reviews the efficacy, mechanism and related immune regulation of epigallocatechin-3-gallate (EGCG) as an anti-pathogenic microorganism drug. EGCG mainly shows both direct and indirect anti-infection effects. EGCG directly inhibits early infection by interfering with the adsorption on host cells, inhibiting virus replication and reducing bacterial biofilm formation and toxin release; EGCG indirectly inhibits infection by regulating immune inflammation and antioxidation. At the same time, we reviewed the bioavailability and safety of EGCG in vivo. At present, the bioavailability of EGCG can be improved to some extent using nanostructured drug delivery systems and molecular modification technology in combination with other drugs. This study provides a theoretical basis for the development of EGCG as an adjuvant drug for anti-pathogenic microorganisms.


Subject(s)
Anti-Infective Agents/pharmacology , Catechin/analogs & derivatives , Catechin/pharmacology , Immunologic Factors/pharmacology , Animals , Antioxidants/pharmacology , COVID-19/drug therapy , Coronavirus/drug effects , Hepatitis Viruses/drug effects , Humans , Inflammation/drug therapy , Mycobacterium tuberculosis/drug effects , Orthomyxoviridae/drug effects , Oxidative Stress/drug effects , SARS-CoV-2/drug effects , Virus Replication/drug effects
18.
Front Immunol ; 12: 722027, 2021.
Article in English | MEDLINE | ID: covidwho-1399138

ABSTRACT

Approximately half of the SARS-CoV-2 infections occur without apparent symptoms, raising questions regarding long-term humoral immunity in asymptomatic individuals. Plasma levels of immunoglobulin G (IgG) and M (IgM) against the viral spike or nucleoprotein were determined for 25,091 individuals enrolled in a surveillance program in Wuhan, China. We compared 405 asymptomatic individuals who mounted a detectable antibody response with 459 symptomatic COVID-19 patients. The well-defined duration of the SARS-CoV-2 endemic in Wuhan allowed a side-by-side comparison of antibody responses following symptomatic and asymptomatic infections without subsequent antigen re-exposure. IgM responses rapidly declined in both groups. However, both the prevalence and durability of IgG responses and neutralizing capacities correlated positively with symptoms. Regardless of sex, age, and body weight, asymptomatic individuals lost their SARS-CoV-2-specific IgG antibodies more often and rapidly than symptomatic patients did. These findings have important implications for immunity and favour immunization programs including individuals after asymptomatic infections.


Subject(s)
Antibodies, Viral/blood , Asymptomatic Infections/epidemiology , COVID-19/immunology , Immunity, Humoral , SARS-CoV-2/immunology , Adult , Antibodies, Neutralizing/immunology , Antibody Formation , COVID-19/epidemiology , China , Epidemiological Monitoring , Female , Humans , Immunoglobulin G/immunology , Immunoglobulin M/immunology , Male , Middle Aged , Retrospective Studies , SARS-CoV-2/pathogenicity , Young Adult
19.
Environ Res ; 200: 111751, 2021 09.
Article in English | MEDLINE | ID: covidwho-1322097

ABSTRACT

A numerical study was conducted on the effects of ambient temperature and humidity on the transportation of sodium chloride particles (100 nm-1 µm) in a human airway model ranging from the nasal cavity to bronchi. A mucus-tissue structure was adopted to model the mass and heat transfer on the airway surface boundary. The temperature and humidity distributions of the respiratory flow were calculated and then the interaction between the particle and water vapor was further analyzed. It was predicted that the particle size grew to the ratio of 5-6 under subsaturation conditions because of hygroscopicity, which shifted the deposition efficiency in opposite directions on dependence of the initial particle size. However, the particles could be drastically raised to 40 times of the initial 100 nm diameter if the supersaturation-induced condensation was established, that was prone to occur under the cold-dry condition, and consequently promoted the deposition significantly. Such behavior might effectively contribute to the revitalized coronavirus disease 2019 (COVID-19) pandemic in addition to the more active virus itself in winter.


Subject(s)
COVID-19 , Humans , Humidity , Particle Size , Respiratory System , SARS-CoV-2 , Temperature
20.
Front Immunol ; 12: 708523, 2021.
Article in English | MEDLINE | ID: covidwho-1295646

ABSTRACT

Major advances have been made in understanding the dynamics of humoral immunity briefly after the acute coronavirus disease 2019 (COVID-19). However, knowledge concerning long-term kinetics of antibody responses in convalescent patients is limited. During a one-year period post symptom onset, we longitudinally collected 162 samples from 76 patients and quantified IgM and IgG antibodies recognizing the nucleocapsid (N) protein or the receptor binding domain (RBD) of the spike protein (S). After one year, approximately 90% of recovered patients still had detectable SARS-CoV-2-specific IgG antibodies recognizing N and RBD-S. Intriguingly, neutralizing activity was only detectable in ~43% of patients. When neutralization tests against the E484K-mutated variant of concern (VOC) B.1.351 (initially identified in South Africa) were performed among patients who neutralize the original virus, the capacity to neutralize was even further diminished to 22.6% of donors. Despite declining N- and S-specific IgG titers, a considerable fraction of recovered patients had detectable neutralizing activity one year after infection. However, neutralizing capacities, in particular against an E484K-mutated VOC were only detectable in a minority of patients one year after symptomatic COVID-19. Our findings shed light on the kinetics of long-term immune responses after natural SARS-CoV-2 infection and argue for vaccinations of individuals who experienced a natural infection to protect against emerging VOC.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/immunology , Immunoglobulin G/blood , Immunoglobulin M/blood , SARS-CoV-2/immunology , Aged , Antibody Formation/immunology , COVID-19/therapy , Convalescence , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Male , Middle Aged , Phosphoproteins/immunology , Spike Glycoprotein, Coronavirus/immunology , Time Factors
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