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1.
Emerg Microbes Infect ; : 1-52, 2022 Apr 05.
Article in English | MEDLINE | ID: covidwho-1774288

ABSTRACT

SARS-CoV-2 infection causes most cases of severe illness and fatality in older age groups. Over 92% of the Chinese population aged ≥12 years has been fully vaccinated against COVID-19 (albeit with vaccines developed against historical lineages). At the end of October 2021, the vaccination program has been extended to children aged 3-11 years. Here, we aim to assess whether, in this vaccination landscape, the importation of Delta variant infections could shift COVID-19 burden from adults to children. We developed an age-structured susceptible-infectious-removed model of SARS-CoV-2 transmission to simulate epidemics triggered by the importation of Delta variant infections and project the age-specific incidence of SARS-CoV-2 infections, cases, hospitalisations, intensive care unit (ICU) admissions, and deaths. In the context of the vaccination program targeting individuals aged ≥12 years, and in the absence of non-pharmaceutical interventions, the importation of Delta variant infections could have led to widespread transmission and substantial disease burden in mainland China, even with vaccination coverage as high as 89% across the eligible age groups. Extending the vaccination roll-out to include children aged 3-11 years (as it was the case since the end of October 2021) is estimated to dramatically decrease the burden of symptomatic infections and hospitalisations within this age group (39% and 68%, respectively, when considering a vaccination coverage of 87%), but would have a low impact on protecting infants. Our findings highlight the importance of including children among the target population and the need to strengthen vaccination efforts by increasing vaccine effectiveness.Trial registration: ClinicalTrials.gov identifier: NCT04847102..

2.
BMC Med ; 20(1): 130, 2022 Apr 04.
Article in English | MEDLINE | ID: covidwho-1770537

ABSTRACT

BACKGROUND: Hundreds of millions of doses of coronavirus disease 2019 (COVID-19) vaccines have been administered globally, but progress on vaccination varies considerably between countries. We aimed to provide an overall picture of COVID-19 vaccination campaigns, including policy, coverage, and demand of COVID-19 vaccines. METHODS: We conducted a descriptive study of vaccination policy and doses administered data obtained from multiple public sources as of 8 February 2022. We used these data to develop coverage indicators and explore associations of vaccine coverage with socioeconomic and healthcare-related factors. We estimated vaccine demand as numbers of doses required to complete vaccination of countries' target populations according to their national immunization program policies. RESULTS: Messenger RNA and adenovirus vectored vaccines were the most commonly used COVID-19 vaccines in high-income countries, while adenovirus vectored vaccines were the most widely used vaccines worldwide (180 countries). One hundred ninety-two countries have authorized vaccines for the general public, with 40.1% (77/192) targeting individuals over 12 years and 32.3% (62/192) targeting those ≥ 5 years. Forty-eight and 151 countries have started additional-dose and booster-dose vaccination programs, respectively. Globally, there have been 162.1 doses administered per 100 individuals in target populations, with marked inter-region and inter-country heterogeneity. Completed vaccination series coverage ranged from 0.1% to more than 95.0% of country target populations, and numbers of doses administered per 100 individuals in target populations ranged from 0.2 to 308.6. Doses administered per 100 individuals in whole populations correlated with healthcare access and quality index (R2 = 0.59), socio-demographic index (R2 = 0.52), and gross domestic product per capita (R2 = 0.61). At least 6.4 billion doses will be required to complete interim vaccination programs-3.3 billion for primary immunization and 3.1 billion for additional/booster programs. Globally, 0.53 and 0.74 doses per individual in target populations are needed for primary immunization and additional/booster dose programs, respectively. CONCLUSIONS: There is wide country-level disparity and inequity in COVID-19 vaccines rollout, suggesting large gaps in immunity, especially in low-income countries.


Subject(s)
COVID-19 Vaccines , COVID-19 , COVID-19/epidemiology , COVID-19/prevention & control , Humans , Immunization Programs , Policy , Vaccination Coverage
3.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-331890

ABSTRACT

After the adoption of a dynamic zero-COVID strategy in China for nearly two years, whether and for how long this policy can remain in place is unclear. The debate has thus shifted towards the identification of mitigation strategies capable to prevent the disruption of the healthcare system, should a nationwide epidemic caused by the SARS-CoV-2 Omicron variant start to unfold. To this aim, we developed a mathematical model of SARS-CoV-2 transmission tailored to the unique immunization and epidemiological situation of China. We find that the level of immunity induced by the current vaccination campaign would be insufficient to prevent overwhelming the healthcare system and major losses of human lives. Instead, a synergetic strategy would be needed and based on 1) a heterologous booster vaccination campaign, 2) treating 50% of symptomatic cases with an antiviral with an 80% efficacy in preventing severe outcomes, and 3) the adoption of non-pharmaceutical interventions (NPIs) capable of reducing Rt to ≤2. Protecting vulnerable individuals by ensuring accessibility to vaccines and antivirals, and maintaining a certain degree of NPIs should be emphasised in a future mitigation policy, possibly supported by strengthening critical care capacity and the development of highly efficacious vaccines with long-lasting immunity.

4.
Mater Today Bio ; 14: 100231, 2022 Mar.
Article in English | MEDLINE | ID: covidwho-1717771

ABSTRACT

Infectious diseases (such as Corona Virus Disease 2019) and tumors pose a tremendous challenge to global public health. Early diagnosis of infectious diseases and tumors can lead to effective control and early intervention of the patient's condition. Over the past few decades, carbon nanomaterials (CNs) have attracted widespread attention in different scientific disciplines. In the field of biomedicine, carbon nanotubes, graphene, carbon quantum dots and fullerenes have the ability of improving the accuracy of the diagnosis by the improvement of the diagnostic approaches. Therefore, this review highlights their applications in the diagnosis of infectious diseases and tumors over the past five years. Recent advances in the field of biosensing, bioimaging, and nucleic acid amplification by such CNs are introduced and discussed, emphasizing the importance of their unique properties in infectious disease and tumor diagnosis and the challenges and opportunities that exist for future clinical applications. Although the application of CNs in the diagnosis of several diseases is still at a beginning stage, biosensors, bioimaging technologies and nucleic acid amplification technologies built on CNs represent a new generation of promising diagnostic tools that further support their potential application in infectious disease and tumor diagnosis.

5.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-324275

ABSTRACT

We profiled the circulating immune cells in COVID-19 patients during the active disease and recovery phases via single cell RNA, TCR and BCR sequencing in order to elucidate the key anti-virus adaptive immune responses, and explore potential immunomodulatory therapeutic strategies. T cell competence plays a dominant role in anti-SARS-CoV-2 immunity. Clonally expanded CD4 T effector cells averted CD8 T cell exhaustion, and expansion of multiple CD8 T effector/memory clones was correlated with rapid virus clearance. In contrast, the patients lacking CD4 T EFF cell clonal expansion harbored exhausted CD8 T EFF cells co-expressing multiple co-inhibitory molecules. In addition, more than 90% of the exhausted cells expressed at least 2 and more than half of exhausted cells expressed at least 4 inhibitory molecules. Furthermore, co-expression of LAG3, Galectin-9, and SLAMF6 is the inhibitory molecule expression signature of exhausted T cell population in SARS-CoV-2 infection. Our findings indicate that LAG3-based immune checkpoint blockade is a promising strategy for treating COVID-19.

7.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-318900

ABSTRACT

The spike protein of SARS-CoV-2 (SARS-CoV-2-S) helps the virus attach to and infect human cells. W<a>ith various computational methods applied in this work, the accessibility of its RBD to ACE2, its key residues for stronger binding to ACE2 than the SARS-CoV spike (SARS-CoV-S), the origin of the stronger binding, and its potential sites for drug and antibody design</a> were explored. It was found that the SARS-CoV-2-S could bind ACE2 with an RBD-angle ranging from 52.2º to 84.8º, which demonstrated that the RBD does not need to fully open to bind ACE2. Free energy calculation by an MM/GBSA approach not only revealed much stronger binding of SARS-CoV-2-S to ACE2 (ΔG=-21.7~-29.9 kcal/mol) than SARS-CoV-S (ΔG=-10.2~-16.4 kcal/mol) at different RBD-angles but also demonstrated that the binding becomes increasingly stronger as the RBD-angle increases. In comparison with the experimental results, the free energy decomposition disclosed more key residues interacting strongly with ACE2 than with the SARS-CoV-S, among which the Q493 might be the decisive residue variation (-5.84 kcal/mol) to the strong binding. With the mutation of all 18 different residues of SARS-CoV-S on the spike-ACE2 interface to the corresponding residues of SARS-CoV-2-S, it was found that the mutated SARS-CoV-S has almost the same binding affinity as SARS-CoV-2-S to ACE2, demonstrating that the remaining mutations outside the spike-ACE2 interface have little effect on its binding affinity to ACE2. Simulation of the conformational change pathway from “down” to “up” states disclosed <a>5 potential ligand-binding pockets correlated to the conformational change.</a> Taking together the key residues, accessible RBD-angle and pocket correlation, potential sites for drug and antibody design were proposed, which should be helpful for interpreting the high infectiousness of SARS-CoV-2 and for developing a cure.

8.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-315364

ABSTRACT

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China, and rapidly spread worldwide. This new emerging pathogen is highly transmittable and can cause fatal disease. More than 35 million cases have been confirmed and the fatality was about 2.9% up to October 9 2020. However, the original and intermediate hosts of SARS-CoV-2 remain unknown. Here, a total of 3160 poultry samples collected from 14 provinces between September and December 2019 in China were tested for the purpose of traceable surveillance for SARS-CoV-2 infection. The results indicated that all samples were SARS-CoV-2 negative, and a total of 593 avian coronaviruses were detected, including 485 avian infectious bronchitis viruses, 72 duck coronaviruses and 36 pigeon coronaviruses. The positive rates of avian infectious bronchitis virus, duck coronavirus, and pigeon coronavirus were 15.35%, 2.28% and 1.14%, respectively. Our surveillance demonstrated the diversities of avian coronaviruses in China, and higher prevalence were also recognized in some regions. The possibility of SARS-CoV-2 originating from the known avian-origin coronaviruses can be preliminarily ruled out. More surveillance and research on avian coronaviruses should be strengthened for better understanding the diversity, distribution, cross-species transmission and clinical significance of these viruses.

9.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315329

ABSTRACT

Background: The Coronavirus Disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pandemic, posing a serious threat to public health worldwide. Whether survivors of COVID-19 pneumonia may be at risk of pulmonary fibrosis is still unknown.Methods: This study involves 462 laboratory confirmed patients with COVID-19 who were admitted to Shenzhen Third People’s Hospital. A total of 457 patients underwent thin-section chest CT scans during the hospitalization or after discharge to identify the pulmonary lesion. A total of 287 patients were followed up from 90 days to 150 days after the onset of the disease.Finding: 397 (86.87%), 311 (74.40%), 222 (79.56%), 141 (68.12%) and 49 (62.03%) patients developed with pulmonary fibrosis during the 0-30, 31-60, 61-90, 91-120 and >120 days after onset, respectively. Reversal of pulmonary fibrosis were found in 18 (4.53%), 61 (19.61%), 40 (18.02%), 54 (38.30%) and 24 (48.98%) COVID-19 patients during the 0-30, 31-60, 61-90, 91-120 and >120 days after onset, respectively. It was observed that Age, BMI, Fever, and Highest PCT were predictive factors for sustaining fibrosis even after 90 days from onset. Only a fraction of COVID-19 patients suffered with abnormal lung function after 90 days from onset.Interpretation: Long-term pulmonary fibrosis was more likely to develop in patients with older age, high BMI, severe/critical condition, fever, long time to turn the viral RNA negative, pre-existing disease and delay to admission. Fibrosis developed in COVID-19 patients could be reversed in about a half of the patients after 120 days from onset. The pulmonary function of most of COVID-19 patients with pulmonary fibrosis could turn to normal condition after three months from onset.Funding Statement: Shenzhen Science and Technology Research and Development Project (202002073000001 and 202002073000002), Shenzhen Fund for Guangdong Provincial High-level Clinical Key Specialties (SZGSP011).Declaration of Interests: The authors declare no competing interests.Ethics Approval Statement: This study was conducted at Shenzhen Third People's Hospital and approved by the Ethics Committees, each patient gave written informed consent.

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-315328

ABSTRACT

Background: Thousands of the Coronavirus Disease 2019 (COVID-19) patients have been discharged from hospitals, persistent follow-up studies are required to evaluate the prevalence of post-COVID-19 fibrosis. Methods: : This study involves 462 laboratory confirmed patients with COVID-19 who were admitted to Shenzhen Third People’s Hospital from January 11, 2020 to April 26, 2020. A total of 457 patients underwent thin-section chest CT scans during the hospitalization or after discharge to identify the pulmonary lesion. A total of 287 patients were followed up from 90 days to 150 days after the onset of the disease, and lung function tests were conducted in about three months after the onset. The risk factors affecting the persistence of pulmonary fibrosis were identified through regression analysis and the prediction model of the persistence of pulmonary fibrosis was established. Results: : Parenchymal bands, irregular interfaces, reticulation and traction bronchiectasis were the most common CT features in all COVID-19 patients. During the 0-30, 31-60, 61-90, 91-120 and >120 days after onset, 86.87%, 74.40%, 79.56%, 68.12% and 62.03% patients developed with pulmonary fibrosis and 4.53%, 19.61%, 18.02%, 38.30% and 48.98% patients reversed pulmonary fibrosis, respectively. It was observed that Age, BMI, Fever, and Highest PCT were predictive factors for sustaining fibrosis even after 90 days from onset. A predictive model of the persistence with pulmonary fibrosis was developed based-on the Logistic Regression method with an accuracy, PPV, NPV, Sensitivity and Specificity of the model of 76%, 71%, 79%, 67%, and 82%, respectively. More than half of COVID-19 patients revealed abnormal condition in lung function after 90 days from onset, and the ratio of abnormal lung function did not differ on a statistically significant level between the fibrotic and non-fibrotic groups. Conclusions: : Persistent pulmonary fibrosis was more likely to develop in patients with older age, high BMI, severe/critical condition, fever, long time to turn the viral RNA negative, pre-existing disease and delay to admission. Fibrosis developed in COVID-19 patients could be reversed in about a third of the patients after 120 days from onset. The pulmonary function of less than half of COVID-19 patients could turn to normal condition after three months from onset. An effective prediction model with an average Area Under the Curve (AUC) of 0.84 was established to predict the persistence of pulmonary fibrosis in COVID-19 patients for early diagnosis.

11.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-310722

ABSTRACT

Background: In December 2019, Wuhan witnessed the outbreak of an “unexplained pneumonia” caused by a novel coronavirus strain infection and was dubbed the COVID-19 by the WHO. The disease quickly spread to China. This study aimed to investigate the disease’s evolving epidemiological history, as well as analyze the clinical and CT imaging characteristics, treatment regimens, and patients’ prognosis. Methods: : This was a retrospective study whose cases were 64 patients with a confirmed diagnosis of COVID-19. The clinical data were obtained from patients who were admitted to the isolation ward from 21 January 2020 to 19 February 2020. Results: : 60 out of 64 patients had a definitive history of exposure to people who had traveled from Wuhan City. The median time from onset of symptoms to first hospital admission was 3.9±1.9 days. The initial symptoms included fever (46/64), dry cough (38/64), fatigue or myalgia (23/64), sore throat (10/64), diarrhea (3/64) along with late-onset symptoms like chest pains (2/64) and headaches (2/64). The majority of the patients (43/64) had normal white blood cell counts while 29.7 % (19/64) had leukopenia. Only two patients (3.1 %) presented with leukocytosis. 58 of the 64patients had abnormal radiological findings on chest CTs. The first chest CTs (within 2 days) was more sensitive in detecting COVID-19 infection (85.9 %) compared to the initial RT-PCR (56.3 %;p<0.01). The CTs showed lesions in multiple lung lobes in three-quarters of the patients while 15.6 % had lesions localized to one lobe. Most of the lesions were typically dense with ground-glass opacity co-existing with consolidation or cord-like shadows. Most of these patients (50/64) have recovered and got discharged giving a mean length of hospital stay of 13.5±4.8 days. Our hospital unit has not reported any COVID-19 related death so far. Conclusions: : Early intervention in COVID-19 disease improves patients’ prognosis. Our data demonstrate the superiority of early radiological tests ahead of RT-PCR. The initial and dynamic CT changes in COVID-19 patients along with other clinical data shared above can better guide clinical decision making.

12.
BMC Med ; 20(1): 37, 2022 01 31.
Article in English | MEDLINE | ID: covidwho-1662418

ABSTRACT

BACKGROUND: To allow a return to a pre-COVID-19 lifestyle, virtually every country has initiated a vaccination program to mitigate severe disease burden and control transmission. However, it remains to be seen whether herd immunity will be within reach of these programs. METHODS: We developed a compartmental model of SARS-CoV-2 transmission for China, a population with low prior immunity from natural infection. Two vaccination programs were tested and model-based estimates of the immunity level in the population were provided. RESULTS: We found that it is unlikely to reach herd immunity for the Delta variant given the relatively low efficacy of the vaccines used in China throughout 2021 and the lack of prior natural immunity. We estimated that, assuming a vaccine efficacy of 90% against the infection, vaccine-induced herd immunity would require a coverage of 93% or higher of the Chinese population. However, even when vaccine-induced herd immunity is not reached, we estimated that vaccination programs can reduce SARS-CoV-2 infections by 50-62% in case of an all-or-nothing vaccine model and an epidemic starts to unfold on December 1, 2021. CONCLUSIONS: Efforts should be taken to increase population's confidence and willingness to be vaccinated and to develop highly efficacious vaccines for a wide age range.


Subject(s)
COVID-19 , Epidemics , Viral Vaccines , China/epidemiology , Humans , SARS-CoV-2
13.
Phys Chem Chem Phys ; 24(5): 3410-3419, 2022 Feb 02.
Article in English | MEDLINE | ID: covidwho-1650366

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among all the potential targets studied for developing drugs and antibodies, the spike (S) protein is the most striking one, which is on the surface of the virus. In contrast with the intensively investigated immunodominant receptor-binding domain (RBD) of the protein, little is known about the neutralizing antibody binding mechanisms of the N-terminal domain (NTD), let alone the effects of NTD mutations on antibody binding and thereby the risk of immune evasion. Based on 400 ns molecular dynamics simulation for 11 NTD-antibody complexes together with other computational approaches in this study, we investigated critical residues for NTD-antibody binding and their detailed mechanisms. The results show that 36 residues on the NTD including R246, Y144, K147, Y248, L249 and P251 are critically involved in the direct interaction of the NTD with many monoclonal antibodies (mAbs), indicating that the viruses harboring these residue mutations may have a high risk of immune evasion. Binding free energy calculations and an interaction mechanism study reveal that R246I, which is present in the Beta (B.1.351/501Y.V2) variant, may have various impacts on current NTD antibodies through abolishing the hydrogen bonds and electrostatic interaction with the antibodies or affecting other interface residues. Therefore, special attention should be paid to the mutations of these key residues in future antibody and vaccine design and development.


Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Immune Evasion/genetics , Mutation , SARS-CoV-2/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Antibodies, Monoclonal/chemistry , Antibodies, Neutralizing/chemistry , Hydrogen Bonding , Molecular Dynamics Simulation , Protein Binding , Protein Domains/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Thermodynamics
14.
Nat Commun ; 13(1): 322, 2022 01 14.
Article in English | MEDLINE | ID: covidwho-1625443

ABSTRACT

There are contrasting results concerning the effect of reactive school closure on SARS-CoV-2 transmission. To shed light on this controversy, we developed a data-driven computational model of SARS-CoV-2 transmission. We found that by reactively closing classes based on syndromic surveillance, SARS-CoV-2 infections are reduced by no more than 17.3% (95%CI: 8.0-26.8%), due to the low probability of timely identification of infections in the young population. We thus investigated an alternative triggering mechanism based on repeated screening of students using antigen tests. Depending on the contribution of schools to transmission, this strategy can greatly reduce COVID-19 burden even when school contribution to transmission and immunity in the population is low. Moving forward, the adoption of antigen-based screenings in schools could be instrumental to limit COVID-19 burden while vaccines continue to be rolled out.


Subject(s)
COVID-19/epidemiology , COVID-19/prevention & control , Models, Statistical , Quarantine/organization & administration , SARS-CoV-2/pathogenicity , Schools/organization & administration , COVID-19/diagnosis , COVID-19/transmission , COVID-19 Serological Testing , Computer Simulation , Humans , Italy/epidemiology , Mass Screening/trends , Physical Distancing , SARS-CoV-2/growth & development , SARS-CoV-2/immunology , Schools/legislation & jurisprudence , Students/legislation & jurisprudence
15.
Am J Chin Med ; 49(8): 1965-1999, 2021.
Article in English | MEDLINE | ID: covidwho-1599109

ABSTRACT

Pulmonary fibrosis (PF) is a chronic and irreversible interstitial lung disease that even threatens the lives of some patients infected with COVID-19. PF is a multicellular pathological process, including the initial injuries of epithelial cells, recruitment of inflammatory cells, epithelial-mesenchymal transition, activation and differentiation of fibroblasts, etc. TGF-[Formula: see text]1 acts as a key effect factor that participates in these cellular processes of PF. Recently, much attention was paid to inhibiting TGF-[Formula: see text]1 mediated cell processes in the treatment of PF with Chinese herbal medicines (CHM), an important part of traditional Chinese medicine. Here, this review first summarized the effects of TGF-[Formula: see text]1 in different cellular processes of PF. Then, this review summarized the recent research on CHM (compounds, multi-components, single medicines and prescriptions) to directly and/or indirectly inhibit TGF-[Formula: see text]1 signaling (TLRs, PPARs, micrRNA, etc.) in PF. Most of the research focused on CHM natural compounds, including but not limited to alkaloids, flavonoids, phenols and terpenes. After review, the research perspectives of CHM on TGF-[Formula: see text]1 inhibition in PF were further discussed. This review hopes that revealing the inhibiting effects of CHM on TGF-[Formula: see text]1-mediated cellular processes of PF can promote CHM to be better understood and utilized, thus transforming the therapeutic activities of CHM into practice.


Subject(s)
Cell Physiological Phenomena/drug effects , Drugs, Chinese Herbal/therapeutic use , Pulmonary Fibrosis/drug therapy , Signal Transduction/drug effects , Transforming Growth Factor beta1/antagonists & inhibitors , COVID-19/complications , COVID-19/metabolism , COVID-19/virology , Humans , Medicine, Chinese Traditional/methods , Phytotherapy/methods , Pulmonary Fibrosis/complications , Pulmonary Fibrosis/metabolism , SARS-CoV-2/physiology , Transforming Growth Factor beta1/metabolism
16.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-295323

ABSTRACT

Background To allow a return to a pre-COVID-19 lifestyle, virtually every country has initiated a vaccination program to mitigate severe disease burden and control transmission. However, it remains to be seen whether herd immunity will be within reach of these programs. Methods We developed a data-driven model of SARS-CoV-2 transmission for China, a population with low prior immunity from natural infection. The model is calibrated considering COVID-19 natural history and the estimated transmissibility of the Delta variant. Three vaccination programs are tested, including the one currently enacted in China and model-based estimates of the herd immunity level are provided. Results We found that it is unlike to reach herd immunity for the Delta variant given the relatively low efficacy of the vaccines used in China throughout 2021, the exclusion of underage individuals from the targeted population, and the lack of prior natural immunity. We estimate that, assuming a vaccine efficacy of 90% against the infection, vaccine-induced herd immunity would require a coverage of 93% or higher of the Chinese population. However, even when vaccine-induced herd immunity is not reached, we estimated that vaccination programs can reduce SARS-CoV-2 infections by 53-58% in case of an epidemic starts to unfold in the fall of 2021. Conclusions Efforts should be taken to increase population’s confidence and willingness to be vaccinated and to guarantee highly efficacious vaccines for a wider age range.

17.
Sustainability ; 13(21):11667, 2021.
Article in English | MDPI | ID: covidwho-1480990

ABSTRACT

Since 2019, the novel coronavirus has spread rapidly worldwide, greatly affecting social stability and human health. Pandemic prevention has become China’s primary task in responding to the transmission of COVID-19. Risk mapping and the proposal and implementation of epidemic prevention measures emphasize many research efforts. In this study, we collected location information for confirmed COVID-19 cases in Beijing, Shenyang, Dalian, and Shijiazhuang from 5 October 2020 to 5 January 2021, and selected 15 environmental variables to construct a model that comprehensively considered the parameters affecting the outbreak and spread of COVID-19 epidemics. Annual average temperature, catering, medical facilities, and other variables were processed using ArcGIS 10.3 and classified into three groups, including natural environmental variables, positive socio-environmental variables, and benign socio-environmental variables. We modeled the epidemic risk distribution for each area using the MaxEnt model based on the case occurrence data and environmental variables in four regions, and evaluated the key environmental variables influencing the epidemic distribution. The results showed that medium-risk zones were mainly distributed in Changping and Shunyi in Beijing, while Huanggu District in Shenyang and the southern part of Jinzhou District and the eastern part of Ganjingzi District in Dalian also represented areas at moderate risk of epidemics. For Shijiazhuang, Xinle, Gaocheng and other places were key COVID-19 epidemic spread areas. The jackknife assessment results revealed that positive socio-environmental variables are the most important factors affecting the outbreak and spread of COVID-19. The average contribution rate of the seafood market was 21.12%, and this contribution reached as high as 61.3% in Shenyang. The comprehensive analysis showed that improved seafood market management, strengthened crowd control and information recording, industry-catered specifications, and well-trained employees have become urgently needed prevention strategies in different regions. The comprehensive analysis indicated that the niche model could be used to classify the epidemic risk and propose prevention and control strategies when combined with the assessment results of the jackknife test, thus providing a theoretical basis and information support for suppressing the spread of COVID-19 epidemics.

18.
Virus Res ; 306: 198566, 2021 12.
Article in English | MEDLINE | ID: covidwho-1475120

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in Wuhan, China, and rapidly spread throughout the world. This newly emerging pathogen is highly transmittable and can cause fatal disease. More than 35 million cases have been confirmed, with a fatality rate of about 2.9% to October 9, 2020. However, the original and intermediate hosts of SARS-CoV-2 remain unknown. Here, 3160 poultry samples collected from 14 provinces of China between September and December 2019 were tested for SARS-CoV-2 infection. All the samples were SARS-CoV-2 negative, but 593 avian coronaviruses were detected, including 485 avian infectious bronchitis viruses, 72 duck coronaviruses, and 36 pigeon coronaviruses, with positivity rates of 15.35%, 2.28%, and 1.14%, respectively. Our surveillance demonstrates the diversity of avian coronaviruses in China, with higher prevalence rates in some regions. Furthermore, the possibility that SARS-CoV-2 originated from a known avian-origin coronavirus can be preliminarily ruled out. More surveillance of and research into avian coronaviruses are required to better understand the diversity, distribution, cross-species transmission, and clinical significance of these viruses.


Subject(s)
Bird Diseases/virology , Coronavirus Infections/veterinary , Coronavirus/genetics , Coronavirus/isolation & purification , Genetic Variation , Animals , Bird Diseases/epidemiology , Chickens/virology , China/epidemiology , Columbidae/virology , Coronavirus/classification , Coronavirus Infections/epidemiology , Coronavirus Infections/virology , Ducks/virology , Epidemiological Monitoring , Geese/virology , Phylogeny , Poultry Diseases/epidemiology , Poultry Diseases/virology , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification
19.
Viruses ; 13(10)2021 09 29.
Article in English | MEDLINE | ID: covidwho-1441884

ABSTRACT

Bats have been identified as natural reservoirs of a variety of coronaviruses. They harbor at least 19 of the 33 defined species of alpha- and betacoronaviruses. Previously, the bat coronavirus HKU10 was found in two bat species of different suborders, Rousettus leschenaultia and Hipposideros pomona, in south China. However, its geographic distribution and evolution history are not fully investigated. Here, we screened this viral species by a nested reverse transcriptase PCR in our archived samples collected over 10 years from 25 provinces of China and one province of Laos. From 8004 bat fecal samples, 26 were found to be positive for bat coronavirus HKU10 (BtCoV HKU10). New habitats of BtCoV HKU10 were found in the Yunnan, Guangxi, and Hainan Provinces of China, and Louang Namtha Province in Laos. In addition to H. pomona, BtCoV HKU10 variants were found circulating in Aselliscus stoliczkanus and Hipposideros larvatus. We sequenced full-length genomes of 17 newly discovered BtCoV HKU10 strains and compared them with previously published sequences. Our results revealed a much higher genetic diversity of BtCoV HKU10, particularly in spike genes and accessory genes. Besides the two previously reported lineages, we found six novel lineages in their new habitats, three of which were located in Yunnan province. The genotypes of these viruses are closely related to sampling locations based on polyproteins, and correlated to bat species based on spike genes. Combining phylogenetic analysis, selective pressure, and molecular-clock calculation, we demonstrated that Yunnan bats harbor a gene pool of BtCoV HKU10, with H. pomona as a natural reservoir. The cell tropism test using spike-pseudotyped lentivirus system showed that BtCoV HKU10 could enter cells from human and bat, suggesting a potential interspecies spillover. Continuous studies on these bat coronaviruses will expand our understanding of the evolution and genetic diversity of coronaviruses, and provide a prewarning of potential zoonotic diseases from bats.


Subject(s)
Alphacoronavirus/genetics , Chiroptera/virology , Alphacoronavirus/pathogenicity , Animals , Base Sequence/genetics , Biological Evolution , China , Chiroptera/genetics , Coronavirus/genetics , Coronavirus/pathogenicity , Coronavirus Infections/virology , Evolution, Molecular , Genetic Variation/genetics , Genome, Viral/genetics , Genotype , Phylogeny , Sequence Analysis, DNA/methods , Viral Proteins/genetics
20.
Brief Bioinform ; 23(1)2022 01 17.
Article in English | MEDLINE | ID: covidwho-1434364

ABSTRACT

Although the current coronavirus disease 2019 (COVID-19) vaccines have been used worldwide to halt spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the emergence of new SARS-CoV-2 variants with E484K mutation shows significant resistance to the neutralization of vaccine sera. To better understand the resistant mechanism, we calculated the binding affinities of 26 antibodies to wild-type (WT) spike protein and to the protein harboring E484K mutation, respectively. The results showed that most antibodies (~85%) have weaker binding affinities to the E484K mutated spike protein than to the WT, indicating the high risk of immune evasion of the mutated virus from most of current antibodies. Binding free energy decomposition revealed that the residue E484 forms attraction with most antibodies, while the K484 has repulsion from most antibodies, which should be the main reason of the weaker binding affinities of E484K mutant to most antibodies. Impressively, a monoclonal antibody (mAb) combination was found to have much stronger binding affinity with E484K mutant than WT, which may work well against the mutated virus. Based on binding free energy decomposition, we predicted that the mutation of four more residues on receptor-binding domain (RBD) of spike protein, viz., F490, V483, G485 and S494, may have high risk of immune evasion, which we should pay close attention on during the development of new mAb therapeutics.


Subject(s)
Antibodies, Neutralizing , Antibodies, Viral , Immune Evasion , Molecular Dynamics Simulation , Mutation, Missense , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Amino Acid Substitution , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/immunology , Antibodies, Viral/chemistry , Antibodies, Viral/immunology , Humans , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
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