Impactful publications of critical care medicine research in China: A bibliometric analysis.

Background: Although publications have been increasing rapidly, the research quality has yet to improve in the field of critical care medicine (CCM) in China. This study aimed at investigating the current status of and the influential factors for impactful publications in CCM research by Chinese authors. Methods: Publications by authors with the affiliation of critical care medicine department or intensive care unit (CCM/ICU) in Chinese as well as American hospitals from 2001 to 2020 were retrieved from the Web of Science Core Collection (WoSCC) database for this bibliometric analysis. Moreover, statistical analyses to test factors affecting impactful publications by Chinese authors were performed. Results: Of 13,487 articles retrieved by this search strategy, 6,622 were published by Chinese authors as first or corresponding authors. The annual publications by Chinese authors have been rapidly increasing from 2001 to 2020, and so did the citations to these articles. However, the proportion in the world of publications by Chinese authors was much less than that by American authors each year [M (IQR): 1.85 (9.592) vs. 27.77 (7.3), p < 0.001]. In addition, impactful articles were significantly less published by Chinese than by American authors, including articles either in journals with a high impact factor (p < 0.001) or in the top 10 journals in the field of CCM (5.4 vs 13.4%, p < 0.001), and articles with high citation frequency as well (p < 0.001). Moreover, the percentage of impactful publications by Chinese authors was likely associated with academic background and regions of the author's affiliations, funds support, public health events of COVID-19, and collaboration between authors. Conclusion: Our results demonstrated that CCM research in China grew rapidly in the recent 20 years. However, the impactful publications remained limited, largely owing to the shortage of comprehensive research training, inactive collaboration, and underfunded CCM research.

Impactful publications of critical care medicine research in China: A bibliometric analysis

Background Although publications have been increasing rapidly, the research quality has yet to improve in the field of critical care medicine (CCM) in China. This study aimed at investigating the current status of and the influential factors for impactful publications in CCM research by Chinese authors. Methods Publications by authors with the affiliation of critical care medicine department or intensive care unit (CCM/ICU) in Chinese as well as American hospitals from 2001 to 2020 were retrieved from the Web of Science Core Collection (WoSCC) database for this bibliometric analysis. Moreover, statistical analyses to test factors affecting impactful publications by Chinese authors were performed. Results Of 13,487 articles retrieved by this search strategy, 6,622 were published by Chinese authors as first or corresponding authors. The annual publications by Chinese authors have been rapidly increasing from 2001 to 2020, and so did the citations to these articles. However, the proportion in the world of publications by Chinese authors was much less than that by American authors each year [M (IQR): 1.85 (9.592) vs. 27.77 (7.3), p < 0.001]. In addition, impactful articles were significantly less published by Chinese than by American authors, including articles either in journals with a high impact factor (p < 0.001) or in the top 10 journals in the field of CCM (5.4 vs 13.4%, p < 0.001), and articles with high citation frequency as well (p < 0.001). Moreover, the percentage of impactful publications by Chinese authors was likely associated with academic background and regions of the author's affiliations, funds support, public health events of COVID-19, and collaboration between authors. Conclusion Our results demonstrated that CCM research in China grew rapidly in the recent 20 years. However, the impactful publications remained limited, largely owing to the shortage of comprehensive research training, inactive collaboration, and underfunded CCM research.

Vaccination Is Associated With Shorter Time to Target Cycle Threshold Value in Patients With SARS-CoV-2 Omicron Variant.

Background: Limited data are available on the responses to vaccination for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant in the Chinese population. This study aimed to investigate whether vaccination could alter the disease course of SARS-CoV-2 Omicron variant. Methods: A retrospective cohort included 142 patients who had no or mild symptoms and were admitted to our department for centralized isolation after being locally infected with SARS-CoV-2 Omicron variant from March 4 to 30, 2022, in Shanghai, China. Results: Of the 142 subjects with the mean age of 43.1 years, 53.5% were male and 90.8% had been vaccinated before the infection. Comparing the vaccinated with the unvaccinated patients, there was no difference in patient characteristics, but patients with vaccination had shorter time to target cycle threshold value (TtCT) (vaccinated vs. unvaccinated, 12.6 ± 3.4 vs. 14.8 ± 4.7 days, P = 0.039). There was no difference in TtCT between heterogeneous and homologous vaccination. Of subjects with homologous vaccination, 43.1% were vaccinated with CoronaVac (Sinovac Life Science), 47.2% with Sinopharm BBIBP-CorV, 4.9% with Sinopharm WIBP, 3.3% with CanSinoBio, and 1.6% with Zhifei Longcom. No difference in TtCT was observed among different vaccines. Comparing two-dose primary vaccination with three-dose booster vaccination, we found no difference in TtCT either. Conclusion: Vaccination is associated with shorter TtCT in patients with SARS-CoV-2 Omicron variant.

Parallel multistep digital analysis SlipChip demonstrated with the quantification of nucleic acid by digital LAMP-CRISPR.

Digital biological analysis compartmentalizes targets of interest, such as nucleic acids, proteins, and cells, to a single event level and performs detection and further investigation. Microfluidic-based digital biological analysis methods, including digital PCR, digital protein analysis, and digital cell analysis, have demonstrated superior advantages in research applications and clinical diagnostics. However, most of the methods are still based on a one-step "divide and detect" strategy, and it is challenging for these methods to perform further parallel manipulation of reaction partitions to achieve "divide, manipulate, and analyze" capabilities. Here, we present a parallel multistep digital analysis (PAMDA) SlipChip for the parallel multistep manipulation of a large number of droplets for digital biological analysis, demonstrated by the quantification of SARS-CoV-2 nucleic acids by a two-step digital isothermal amplification combined with clustered regularly interspaced short palindromic repeats (CRISPR). This PAMDA SlipChip utilizes a "chain-of-pearl" channel with a self-partitioning droplet formation mechanism that does not require the precise alignment of microfeatures for fluidic loading as the traditional SlipChip design. This device can first generate 2400 3.2 nanoliter droplets to perform digital loop-mediated isothermal amplification (LAMP) and then deliver reagents containing Cas12a protein and crRNA to each individual partition in parallel to simultaneously initiate digital CRISPR detection by a simple multistep slipping operation. This PAMDA SlipChip not only provides a promising tool to perform digital CRISPR with a flexible assay and workflow design but can also be applied for a broad range of applications in digital biological analysis that require multistep manipulation of partitions in parallel.

Neutralizing Antibodies and Cellular Immune Responses Against SARS-CoV-2 Sustained One and a Half Years After Natural Infection.

Background: COVID-19 has caused more than 2.6 billion infections and several million deaths since its outbreak 2 years ago. We know very little about the long-term cellular immune responses and the kinetics of neutralizing antibodies (NAbs) to SARS-CoV-2 because it has emerged only recently in the human population. Methods: We collected blood samples from individuals who were from the first wave of the COVID-19 epidemic in Wuhan between December 30, 2019, and February 24, 2020. We analyzed NAbs to SARS-CoV-2 using pseudoviruses and IgG antibodies to SARS-CoV-2 spike (S) and nucleocapsid (N) protein using enzyme-linked immunosorbent assay in patients' sera and determined SARS-CoV-2-specific T-cell responses of patients with ELISpot assays. Results: We found that 91.9% (57/62) and 88.9% (40/45) of COVID-19 patients had NAbs against SARS-CoV-2 in a year (10-11 months) and one and a half years (17-18 months), respectively, after the onset of illness, indicating that NAbs against SARS-CoV-2 waned slowly and possibly persisted over a long period time. Over 80% of patients had IgG antibodies to SARS-CoV-2 S and N protein one and a half years after illness onset. Most patients also had robust memory T-cell responses against SARS-CoV-2 one and a half years after the illness. Among the patients, 95.6% (43/45) had an IFN-γ-secreting T-cell response and 93.8% (15/16) had an IL-2-secreting T-cell response. The T-cell responses to SARS-CoV-2 were positively correlated with antibodies (including neutralizing antibodies and IgG antibodies to S and N protein) in COVID-19 patients. Eighty percent (4/5) of neutralizing antibody-negative patients also had SARS-CoV-2-specific T-cell response. After long-term infection, protective immunity was independent of disease severity, sex, and age. Conclusions: We concluded that SARS-CoV-2 infection elicited a robust and persistent neutralizing antibody and memory T-cell response in COVID-19 patients, indicating that these sustained immune responses, among most SARS-CoV-2-infected people, may play a crucial role in protection against reinfection.

Characterization of Two Heterogeneous Lethal Mouse-Adapted SARS-CoV-2 Variants Recapitulating Representative Aspects of Human COVID-19

New emerging severe acute respiratory syndrome 2 (SARS-CoV-2) has caused a worldwide pandemic. Several animal models of coronavirus disease 2019 (COVID-19) have been developed and applied to antiviral research. In this study, two lethal mouse-adapted SARS-CoV-2 variants (BMA8 and C57MA14) with different virulence were generated from different hosts, which are characterized by high viral replication titers in the upper and lower respiratory tract, pulmonary pathology, cytokine storm, cellular tropism, lymphopenia, and neutrophilia. Two variants exhibit host genetics-related and age-dependent morbidity and mortality in mice, exquisitely reflecting the clinical manifestation of asymptomatic, moderate, and severe COVID-19 patients. Notably, both variants equally weaken the neutralization capacity of the serum derived from COVID-19 convalescent, but the C57MA14 variant showed a much higher virulence than the BMA8 variant in vitro. Q489H substitution in the receptor-binding domain (RBD) of BMA8 and C57MA14 variants results in the receptors of SARS-CoV-2 switching from human angiotensin-converting enzyme 2 (hACE2) to murine angiotensin-converting enzyme 2 (mACE2). Additionally, A22D and A36V mutation in E protein were first reported in our study, which potentially contributed to the virulence difference between the two variants. Of note, the protective efficacy of the novel bacterium-like particle (BLP) vaccine candidate was validated using the BMA8- or C57MA14-infected aged mouse model. The BMA8 variant- and C57MA14 variant-infected models provide a relatively inexpensive and accessible evaluation platform for assessing the efficacy of vaccines and novel therapeutic approaches. This will promote further research in the transmissibility and pathogenicity mechanisms of SARS-CoV-2.

Slip formation of a high-density droplet array for nucleic acid quantification by digital LAMP with a random-access system.

Digital nucleic acid analysis (digital NAA) is an important tool for the precise quantification of nucleic acids. Various microfluidic-based approaches for digital NAA have been developed, but most methods require complex auxiliary control instruments, cumbersome device fabrication, or inconvenient preparation processes. A SlipChip is a microfluidic device that can generate and manipulate liquid partitions through simple movements of two microfluidic plates in close contact. However, the traditional SlipChip requires accurate alignment of microfeatures on different plates; therefore, the dimensions of the microwells and density of partitions can be constrained. Here, we developed a droplet array SlipChip (da-SlipChip) that can form droplets of various sizes at high density in a single slipping step. This process does not require precise overlapping microfeatures on different plates; therefore, the design flexibility and partition density can be significantly increased. We quantified SARS-CoV-2 nucleic acids extracted from the COVID-19 pseudovirus by digital loop-mediated isothermal amplification (LAMP) on a da-SlipChip with 21 696 of 0.25 nL droplets, and the results were in good agreement with those of the commercial digital PCR method of Stilla. Furthermore, we demonstrated a random-access system with a single-throughput fluorescence imager and a stackable thermal control instrument with nine independent heating modules. This random-access system with the da-SlipChip can greatly improve the total throughput and flexibility for digital isothermal nucleic acid quantification and significantly reduce the total waiting time.

Viral sepsis is a complication in patients with Novel Corona Virus Disease (COVID-19).

BACKGROUND: Until June 23th 2020, 9,195,635 laboratory-confirmed cases of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection have been reported worldwide, including 473,127 deaths. Bacterial infection is the main cause of sepsis, however, sepsis caused by virus is often ignored. Increased awareness, early recognition of viral sepsis, rapid administration of appropriate antiviral drugs, and urgent treatment can significantly reduce deaths of viral sepsis. OBJECTIVES: Given the rapid global spread of novel Corona Virus Disease (COVID-19), coupled with the high rate of missed diagnosis of viral sepsis caused by SARS-CoV-2 infection, it is urgent to evaluate the multiple organ failure score and viral sepsis in COVID-19 patients, so as to determine the clinical characteristics of viral sepsis more accurately and reveal the risk factors related to mortality. METHODS: Here we provide a full description of three cases of viral sepsis and subsequent multiple organ dysfunction (MODS) caused by SARS-CoV-2 infection imported to Guiyang from Wuhan. RESULTS: We analyzed complete laboratory examination, imaging data and treatment methods for the patients and assessed Sepsis-related Organ Failure Assessment score (SOFA score) and Multiple organ dysfunction scores (MOD score) daily, aimed to elucidate the clinical feature of viral sepsis and MODS and to attract enough attention by clinicians. CONCLUSIONS: Therefore, we strongly suggest to daily evaluate SOFA score and MOD score in severe and critically-ill COVID-19 patients, so as to early diagnose and prevention of sepsis and MODS.Given the rapid global spread of novel Corona Virus Disease (COVID-19), coupled with the high rate of missed diagnosis of viral sepsis caused by SARS-CoV-2 infection, it is urgent to evaluate the multiple organ failure score and viral sepsis in COVID-19 patients, so as to determine the clinical characteristics of viral sepsis more accurately and reveal the risk factors related to mortality. Here we provide a full description of three cases of viral sepsis and subsequent multiple organ dysfunction (MODS) caused by SARS-CoV-2 infection imported to Guiyang from Wuhan. We analyzed complete laboratory examination, imaging data and treatment methods for the patients and assessed Sepsis-related Organ Failure Assessment score (SOFA score) and Multiple organ dysfunction scores (MOD score) daily, aimed to elucidate the clinical feature of viral sepsis and MODS and to attract enough attention by clinicians. Therefore, we strongly suggest to daily evaluate SOFA score and MOD score in severe and critically-ill COVID-19 patients, so as to early diagnose and prevention of sepsis and MODS.