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We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average ~1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.
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Objectives: To understand SARS-CoV-2 seroprevalence of convalescents and assess their the immunity. Furthermore, we intend to explore the association between antibody levels and with demographic factors. Methods: 177 COVID-19 convalescents in Sichuan Province were voluntarily participated in our study. 363 serum samples were collected from June, 2020 to November, 2020. Duration of seroprevelance in these convalescents and their demographic characteristics were described, and the risk factors to antibody levels were analysed. Results: Men had more than twice the odds of having IgM antibody positive compared with women (OR=2.419, 95% CI:[1.232, 4.751]). Participants without symptoms were nearly 0.5 times IgG seropositive than those with symptoms (OR=0.455, 95% CI: [0.220, 0.940]). People aged[≥]60 years were nearly 3 times IgG seropositive than those who aged < 20 years (OR=2.986, 95% CI: [1.058, 8.432]). Seroprevalence in asymptomatic declined quicker than symptomatic. Conclusions: Age and gender may affect the antibody levels and seroprevalence. Asymptomatic appeared more easier to turn to seronegative than symptomatic. Keywords: Seroprevalence; SARS-CoV-2; Risk Factors
Subject(s)
COVID-19ABSTRACT
The ongoing of coronavirus disease 2019 (COVID-19) pandemic caused by novel SARS-CoV-2 coronavirus, resulting in economic losses and seriously threating the human health in worldwide, highlighting the urgent need of a stabilized, easily produced and effective preventive vaccine. The SARS-COV-2 spike protein receptor binding region (RBD) plays an important role in the process of viral binding receptor angiotensin-converting enzyme 2 (ACE2) and membrane fusion, making it an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticles vaccine candidates, RBD-Ferritin (24-mer), RBD-mi3 (60-mer) and RBD-I53-50 (120-mer), with the application of covalent bond linking by SpyTag-SpyCatcher system. It was demonstrated that the neutralizing capability of sera from mice immunized with three RBD-conjugated nanoparticles adjuvanted with AddaVax or Sigma Systerm Adjuvant (SAS) after each immunization was ~8- to 120-fold greater than monomeric RBD group in SARS-CoV-2 pseudovirus and authentic virus neutralization assay. Most importantly, sera from RBD-conjugated NPs groups more efficiently blocked the binding of RBD to ACE2 or neutralizing antibody in vitro, a further proof of promising immunization effect. Besides, high physical stability and flexibility in assembly consolidated the benefit for rapid scale-up production of vaccine. These results supported that our designed SARS-CoV-2 RBD-conjugated nanoparticle was competitive vaccine candidate and the carrier nanoparticles could be adopted as universal platform for future vaccine development.
Subject(s)
Coronavirus Infections , Arthritis, Experimental , Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
Background: Since December 2019, 2019-nCoV has emerged in Wuhan, China, the fast pace of transmission is wreaking global public health crisis. Country’s reaction speed is critical for the control of public health emergency (PHE), especially in the early stage of an outbreak. Compared with SARS pandemic, whether has the efficiency of initial public health emergency response to COVID-19 in mainland China been improved? And whether is there still existing vulnerabilities in current PHE system? Studies on this topic are relatively few. We tried to find the answers, evidences and alternatives. Methods: We conducted a retrospective comparative study. The speed of hospital reporting, pathogen identification and government decision-making between SARS and COVID-19 were compared by selecting 5 critical events from initial public health emergency response timeline. Besides, combining with the two pandemics' progress curves, we discussed the characteristics of their peak time.Results:(1) SARS completed the entire initial public health emergency response in 127 days, and COVID-19 completed in 44 days. Response speed has been shorted nearly by 3 times. (2) Both the first SARS and COVID-19 cases were reported in 19 days. It doesn't appear that hospital reporting speed becomes faster. (3) The accumulated time completing pathogen identification were 118 days for SARS and 31 days for COVID-19. The speed has been improved by more than 3 times. (4) 9 days after the completion of pathogen identification, national government made emergency policies for SARS while the interval between pathogen identification and national government's decision-making for COVID-19 was 13 days. (5) The peak time of SARS came about 80 days later than that of COVID-19. But both the two pandemics' peak occurred about 20 days after the national government's decision-making, and then the curves went down dramatically.Conclusions: The speed of initial public health emergency response to pandemic has been improved due to faster identification. However, some deficiencies and challenges in early alert and authorities' decision-making still remain. Therefore, Chinese government should put more stress on improving hospital's sensitivity to new emerging infectious diseases and timeliness of government's decision-making.
Subject(s)
COVID-19 , Communicable Diseases, EmergingABSTRACT
The digestive tract is a target organ attacked by COVID-19. It is also the earliest affected organ other than the lung and must bear side effects from the anti-virus chemotherapy such as LPV/r. In this article, we aim to provide practical recommendations for a nutritional and metabolic management strategy for severe corona virus disease-19 (COVID-19) patients. These recommendations are based on the newest pathophysiological findings on the risk factors of malnutrition for COVID-19. We also systematically retrieve literatures on nutritional therapy for acute lung injuries from international and Chinese databases according to evidence-based principles. Our suggestions are: 1) Physicians should be mindful of gut injury when they focus on respiratory support, by monitoring and managing the nutritional status; 2) Periodical and dynamic nutritional risk evaluation is needed; 3) For severe patients, the feeding target of calorie and protein should be down-regulated; 4)The using of ω-3 fatty acids products should be in accordance with pharmacological indications; the forms and dosage should be determined individually.
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Objective@#To explore the possibility of using Lopinave/Litonawe (LPV/r) as treatment for novel coronavirus 2019-nCov pneumonia by systematically review earlier coronavirus studies.@*Methods @#Systematically retrieve relevant clinical studies from Chinese and English databases such as CNKI,VIP,Wangfang Data,CBM,PubMed, Web of Science,EMBASE. In addition, information from Chinese biomedical journals, WHO, US CDC, Chinese CDC websites and the references from published relevant articles were retrieved. The inclusion period is from January 2003 to January 24, 2020. The criteria for inclusion are:(1) studies that aim to compare LPV/r and placebo/standard for SARS, MERS; (2) studies that include at least one clinical outcome; (3) studies with diagnosis criteria meeting WHO requirement on SARS or MERS; (4)data from multiple reports but originated from one study, where we extract information from all reports; (5)guidelines, includes: national or academic guidelines/experts ‘consensus. The exclude criteria are: 1) only have abstracts but no full information; 2) in vitro studies. Two reviewers independently review articles and extract data on study design, patients, diagnosis criteria, regimen, and clinical outcomes (mortality, morbidity, quality of life, steroids dosage, chest image and adverse responses). @*Results@#Two hundred and thirty potential article were found by screening, and narrow down to forty-four articles for evaluation and fnally four studies were included. The results of included studies indicate the early use of LPV/r regimen can reduce the mortality of SARS and MERS, and reduce steroids dosing. @*Conclusions@#ILPV/r can be used as a component of experimental regimen for treat 2019-nCoV pneumonia. It strongly suggests that initiating real world studies to explore the true clinical effects of LPV/r on 2019-nCoV patients.