Biopanning of specific peptide for SARS-CoV-2 nucleocapsid protein and enzyme-linked immunosorbent assay-based antigen assay.

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread worldwide which triggered serious public health issues. The search for rapid and accurate diagnosis, effective prevention, and treatment is urgent. The nucleocapsid protein (NP) of SARS-CoV-2 is one of the main structural proteins expressed and most abundant in the virus, and is considered a diagnostic marker for the accurate and sensitive detection of SARS-CoV-2. Herein, we report the screening of specific peptides from the pIII phage library that bind to SARS-CoV-2 NP. The phage monoclone expressing cyclic peptide N1 (peptide sequence, ACGTKPTKFC, with C&C bridged by disulfide bonding) specifically recognizes SARS-CoV-2 NP. Molecular docking studies reveal that the identified peptide is bound to the "pocket" region on the SARS-CoV-2 NP N-terminal domain mainly by forming a hydrogen bonding network and through hydrophobic interaction. Peptide N1 with the C-terminal linker was synthesized as the capture probe for SARS-CoV-2 NP in ELISA. The peptide-based ELISA was capable of assaying SARS-CoV-2 NP at concentrations as low as 61 pg/mL (∼1.2 pM). Furthermore, the as-proposed method could detect the SARS-CoV-2 virus at limits as low as 50 TCID50 (median tissue culture infective dose)/mL. This study demonstrates that selected peptides are powerful biomolecular tools for SARS-CoV-2 detection, providing a new and inexpensive method of rapidly screening infections as well as rapidly diagnosing coronavirus disease 2019 patients.

Case report: One pediatric liver-transplant recipient with SARS-CoV-2 infection suffering unexplained mixed acidosis.

Background: The management of LT patients during COVID-19 pandemic is important. Immunosuppressants (IS) are key therapy agents after liver transplant. Different ISs have different side effects. Calcineurin inhibitor (CNI) may lead to metabolic acidosis while mycophenolate mofetil (MMF) showed rare nephrotoxicity. We report a post-liver transplant girl who was infected with SARS-CoV-2, developing a severe mixed acidosis 3 months after the transplantation. Her acidosis was improved after withdrawing of MMF, leading the suspicion that acidosis maybe a rare side effect of MMF. Case presentation: A girl was admitted to our hospital due to SARS-CoV-2 infection, 3 months before admission the patient received LT due to Niemann-Pick disease (NPD). During hospitalization, blood gas analysis showed severe mixed acidosis. To relieve mixed acidosis, the patient was given oral rehydration salt and liquid replacement therapy. Considering that immunosuppressants may cause metabolic acidosis, dose of CsA was decreased and MMF was discontinued. Results: However, liquid replacement therapy and decreased CsA dose cannot improve the condition. As an attempt, MMF was discontinued, and 3 days later, the girl's acidosis was relieved, the latest blood gas analysis was normal with the original dose of CsA and no use of MMF or other IS. In addition, we used Naranjo Scale to see if adverse drug reactions (ADRs) existed. The final score was 6 which means MMF contributes to acidosis probably. Conclusion: The girl's mixed acidosis cannot be explained by Niemann-Pick disease and SARS-CoV-2 infection. CNIs could cause metabolic acidosis but declining the dose of CsA didn't improve her acidosis while withdrawing MMF showed a good effect. Together with the Naranjo Scale result, we suspect that acidosis maybe a rare side effect of MMF.

Epidemiological, clinical, and household transmission characteristics of children and adolescents infected with SARS-CoV-2 Omicron variant in Shanghai, China: a retrospective, multicenter observational study.

OBJECTIVES: To describe the epidemiological, clinical, and household transmission characteristics of pediatric COVID-19 cases in Shanghai, China. METHODS: Pediatric patients with COVID-19 hospitalized in Shanghai from March-May 2022 were enrolled in this retrospective, multicenter cohort study. The symptoms and the risk factors associated with disease severity were analyzed. RESULTS: In total, 2620 cases (age range, 24 days-17 years) were enrolled in this study. Of these, 1011 (38.6%) were asymptomatic, whereas 1415 (54.0%), 190 (7.3%), and 4 (0.2%) patients developed mild, moderate, and severe illnesses, respectively. Household infection rate was negatively correlated with household vaccination coverage. Children aged 0-3 years, those who are unvaccinated, those with underlying diseases, and overweight/obese children had a higher risk of developing moderate to severe disease than children aged 12-17 years, those who were vaccinated, those without any underlying disease, and those with normal weight, respectively (all P <0.05). A prolonged duration of viral shedding was associated with disease severity, presence of underlying diseases, vaccination status, and younger age (all P <0.05). CONCLUSION: Children aged younger than 3 years who were not eligible for vaccination had a high risk of developing moderate to severe COVID-19 with a prolonged duration of viral shedding. Vaccination could protect children from COVID-19 at the household level.

Altered gut microbiota composition in children and their caregivers infected with the SARS-CoV-2 Omicron variant.

BACKGROUND: Gut microbiota alterations have been implicated in the pathogenesis of coronavirus disease 2019 (COVID-19). This study aimed to explore gut microbiota changes in a prospective cohort of COVID-19 children and their asymptomatic caregivers infected with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) Omicron variant. METHODS: A total of 186 participants, including 59 COVID-19 children, 50 asymptomatic adult caregivers, 52 healthy children (HC), and 25 healthy adults (HA), were recruited between 15 April and 31 May 2022. The gut microbiota composition was determined by 16S rRNA gene sequencing in fecal samples collected from the participants. Gut microbiota functional profiling was performed by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) software. RESULTS: The gut microbiota analysis of beta diversity revealed that the fecal microbial community of COVID-19 children remained far distantly related to HC. The relative abundances of the phyla Actinobacteria and Firmicutes were decreased, whereas Bacteroidetes, Proteobacteria, and Verrucomicrobiota were increased in COVID-19 children. Feces from COVID-19 children exhibited notably lower abundances of the genera Blautia, Bifidobacterium, Fusicatenibacter, Streptococcus, and Romboutsia and higher abundances of the genera Prevotella, Lachnoclostridium, Escherichia-Shigella, and Bacteroides than those from HC. The enterotype distributions of COVID-19 children were characterized by a high prevalence of enterotype Bacteroides. Similar changes in gut microbiota compositions were observed in asymptomatic caregivers. Furthermore, the microbial metabolic activities of KEGG (Kyoto Encyclopedia of Genes and Genomes) and COG (cluster of orthologous groups of proteins) pathways were perturbed in feces from subjects infected with the SARS-CoV-2 Omicron variant. CONCLUSION: Our data reveal altered gut microbiota compositions in both COVID-19 children and their asymptomatic caregivers infected with the SARS-CoV-2 Omicron variant, which further implicates the critical role of gut microbiota in COVID-19 pathogenesis.

[Clinical features of children with coronavirus disease 2019 complicated by acute encephalitis and related research advances]. / æ–°åž‹å† çŠ¶ç— æ¯’è‚ºç‚Žå„¿ç«¥åˆå¹¶æ€¥æ€§è„‘ç‚Žçš„ä¸´åºŠç‰¹ç‚¹åŠç ”ç©¶è¿›å±•.

Coronavirus disease 2019 (COVID-19) has become a worldwide pandemic since the end of 2019. There is an increasing number of reports on nervous system symptoms, among which encephalitis is considered a serious neurological complication of COVID-19, but there are few reports of this complication in China. Acute encephalitis has severe symptoms. If it is not identified early and treated in time, the mortality is high and the prognosis is poor. During the current global epidemic, it is necessary to pay attention to the severe nervous system symptoms of COVID-19. Therefore, this article summarizes the clinical features of COVID-19 complicated by acute encephalitis through literature review and a detailed analysis of medical records, so as to provide a reference for clinicians to deal with the cases of COVID-19 complicated by acute encephalitis.

[Short-term persistent symptoms in preschool children with mild/common coronavirus disease 2019 caused by Omicron variant infection after discharge: a follow-up study]. / Omicronå˜å¼‚æ ªæ„ŸæŸ“çš„è½»åž‹/æ™®é€šåž‹æ–°åž‹å† çŠ¶ç— æ¯’è‚ºç‚Žå­¦é¾„å‰å„¿ç«¥å‡ºé™¢åŽçŸ­æœŸç›¸å ³æŒç»­ç—‡çŠ¶çš„éšè®¿.

OBJECTIVES: To investigate the persistent symptoms in preschool children after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant infection, and to provide a basis for developing follow-up plans after infection and reducing and preventing related symptoms after infection. METHODS: The children, aged 0-5 years, who had Omicron BA.2 infection and were discharged from the pediatric ward of Shanghai Renji Hospital South Branch from April 13 to May 8, 2022, were enrolled as subjects, and related demographic and clinical data were collected. The children were followed up from the time to SARS-CoV-2 clearance for two consecutive tests with an interval of >24 hours till 4-5 weeks after clearance, and telephone follow-up was performed on the primary caregivers to investigate related persistent symptoms. RESULTS: Among the 103 children who met the inclusion criteria, there were 61 boys and 42 girls, with a median age of 18 months. The primary caregivers who had received two or more doses of COVID-19 vaccine accounted for 64.1% (66/103). Fever (98.1%, 101/103) was the most common symptom in these children, followed by cough/expectoration (63.1%, 65/103), gastrointestinal problems (37.9%, 39/103), loss of appetite (30.1%, 31/103), weakness (27.2%, 28/103), and nasal obstruction/runny nose (16.5%, 17/103). The follow-up at 1 month after discharge reported that 44 children (42.7%) had at least one persistent symptom, including respiratory symptoms in 14 children (13.6%) and gastrointestinal problems in 19 children (18.4%). The children whose primary caregivers received two or more doses of COVID-19 vaccine had a significantly shorter time to SARS-CoV-2 clearance than those whose primary caregivers did not receive or only received one dose of COVID-19 vaccine (P<0.05), while there was no significant difference between the two groups in the proportion of children with at least one persistent symptom (P>0.05). CONCLUSIONS: Nearly half of the preschool children may have related persistent symptoms after SARS-CoV-2 Omicron variant infection, mainly gastrointestinal and respiratory symptoms. Most of the symptoms may be mild, and continuous follow-up is needed to observe their outcomes. Vaccination of COVID-19 vaccine for primary caregivers has a certain protective effect on children.

[Effects of vaccines on the viral negative conversion of children with COVID-19].

Objective: To explore the effect of vaccination on viral negative conversion of children with COVID-19. Methods: A retrospective cohort study was conducted. A cohort of 189 children aged 3-14 years with COVID-19 admitted to Renji Hospital (South branch) of Shanghai Jiao Tong University School of Medicine from April 7th to May 19th 2022 was enrolled in the study. According to the vaccination status, the infected children were divided into an unvaccinated group and a vaccinated group. Age, gender, severity, clinical manifestations, and laboratory tests, etc. were compared between groups, by rank sum test or chi-square test. The effects of vaccination on viral negative conversion were analyzed by a Cox mixed-effects regression model. Additionally, a questionnaire survey was conducted among the parents of unvaccinated children to analyze the reasons for not being vaccinated. Results: A total of 189 children aged 3-14 years were enrolled, including 95 males (50.3%) and 94 females (49.7%), aged 5.7 (4.1,8.6) years. There were 117 cases (61.9%) in the unvaccinated group and 72 cases (38.1%) in the vaccinated group. The age of the vaccinated group was higher than that of the unvaccinated group (8.8 (6.8, 10.6) vs. 4.5 (3.6, 5.9) years, Z=9.45, P<0.001). No significant differences were found in clinical manifestations, disease severity, and laboratory results between groups (all P>0.05), except for the occurrence rate of cough symptoms, which was significantly higher in the vaccinated group than in the non-vaccinated group (68.1% (49/72) vs. 50.4% (59/117),χ2=5.67, P=0.017). The Kaplan-Meier survival curve and Cox mixed-effects regression model showed that the time to the viral negative conversion was significantly shorter in the vaccinated group compared with the unvaccinated group (8 (7, 10) vs. 11 (9, 12) d, Z=5.20, P<0.001; adjusted HR=2.19 (95%CI 1.62-2.97)). For questionnaire survey on the reasons for not receiving a vaccination, 115 questionnaires were distributed and 112 valid questionnaires (97.4%) were collected. The main reasons for not being vaccinated were that parents thought that their children were not in the range of appropriate age for vaccination (51 cases, 45.5%) and children were in special physical conditions (47 cases, 42.0%). Conclusion: Vaccination can effectively shorten the negative conversion time of children with COVID-19 and targeted programs should be developed to increase eligible children's vaccination rate for SARS-CoV-2 vaccination.

Clinical features of infants with SARS-CoV-2 infection: a systematic review and meta-analysis.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to coronavirus disease 2019 (COVID-19) and is a public health problem. This meta-analysis reviewed the clinical features of SARS-CoV-2 infection among infants. METHODS: PubMed, Scopus, Web of Science, and the Cochrane Library were searched for studies on clinical features of infants with SARS-CoV-2 published before May 1, 2022. Two authors screened and extracted data on the number of infants with SARS-CoV-2 infection, clinical features, and number of clinical features. The proportion of asymptomatic infection, mild symptoms, moderate symptoms, severe symptoms, and the clinical features were analyzed. RESULTS: Forty-four studies with 6,304 infants with SARS-CoV-2 infections were included in this study. The proportion of asymptomatic infection was 20% (95% CI: 11-28%, I2=97%, P<0.01) in infants with SARS-CoV-2 infections. The proportion of infants with mild, moderate, and severe symptoms was 48% (95% CI: 30-65%, I2=96%, P<0.01), 27% (95% CI: 10-44%, I2=93%, P<0.01), and 8% (95% CI: 0-16%, I2=90%, P<0.01), respectively. Notably, the most common clinical features of infants with SARS-CoV-2 infection were fever (64%), cough (34%), and nasal symptoms (31%). CONCLUSIONS: This meta-analysis found that 20% of infants with SARS-CoV-2 infections were asymptomatic, while most infants with COVID-19 presented with mild symptoms.

Human genetic basis of severe or critical illness in COVID-19.

Coronavirus Disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to considerable morbidity and mortality worldwide. The clinical manifestation of COVID-19 ranges from asymptomatic or mild infection to severe or critical illness, such as respiratory failure, multi-organ dysfunction or even death. Large-scale genetic association studies have indicated that genetic variations affecting SARS-CoV-2 receptors (angiotensin-converting enzymes, transmembrane serine protease-2) and immune components (Interferons, Interleukins, Toll-like receptors and Human leukocyte antigen) are critical host determinants related to the severity of COVID-19. Genetic background, such as 3p21.31 and 9q34.2 loci were also identified to influence outcomes of COVID-19. In this review, we aimed to summarize the current literature focusing on human genetic factors that may contribute to the observed diversified severity of COVID-19. Enhanced understanding of host genetic factors and viral interactions of SARS-CoV-2 could provide scientific bases for personalized preventive measures and precision medicine strategies.

A luciferase based automated assay for rapid and sensitive detection of SARS-CoV-2 antibodies.

The Coronavirus disease 2019 (COVID-19) pandemic brings great challenges to the public health and social economics around the world. As the pandemic continues and the mass vaccination goes on, monitoring the antibodies is particularly important for the epidemiological survey and vaccine assessment. Here, we developed a luciferase immunoprecipitation assay combined with an automated platform to detect anti-Receptor Binding Domain (RBD) antibody, where protein A and protein G modified magnetic beads were used to capture antibodies in serum samples and SARS-CoV-2 RBD was fused with Gaussia luciferase to label the captured target antibodies. The whole detection procedure can be completed within 20 min. The developed assay has proven up to 32 times more sensitive than ELISA for the detection of RBD antibodies. Furthermore, the results of the antibody detection of sera from vaccination as well as convalescence displayed good performance. The automated platform may provide a powerful tool for the control of COVID-19 pandemic by vaccination and the research of SARS-CoV-2 seroconversion.

Human genetic basis of severe or critical illness in COVID-19

Coronavirus Disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to considerable morbidity and mortality worldwide. The clinical manifestation of COVID-19 ranges from asymptomatic or mild infection to severe or critical illness, such as respiratory failure, multi-organ dysfunction or even death. Large-scale genetic association studies have indicated that genetic variations affecting SARS-CoV-2 receptors (angiotensin-converting enzymes, transmembrane serine protease-2) and immune components (Interferons, Interleukins, Toll-like receptors and Human leukocyte antigen) are critical host determinants related to the severity of COVID-19. Genetic background, such as 3p21.31 and 9q34.2 loci were also identified to influence outcomes of COVID-19. In this review, we aimed to summarize the current literature focusing on human genetic factors that may contribute to the observed diversified severity of COVID-19. Enhanced understanding of host genetic factors and viral interactions of SARS-CoV-2 could provide scientific bases for personalized preventive measures and precision medicine strategies.

Management experience of a designated hospital for children with coronavirus disease 2019. / æ–°åž‹å† çŠ¶ç— æ¯’è‚ºç‚Žå„¿ç«¥å®šç‚¹åŒ»é™¢ç®¡ç†ç»éªŒåˆ†äº«.

The global pandemic of coronavirus disease 2019 (COVID-19) has brought great challenges to the traditional medical model. During the outbreak of COVID-19 in Shanghai, China, from March to May, 2022, there was a significant increase in the number of pediatric cases due to high transmissibility, immune escape, and vaccine breakthrough capacity of Omicron variants. The designated hospitals for children with COVID-19 served as a connecting link between children's specialized hospitals and mobile cabin hospitals. From April 7 to June 2, 2022, a total of 871 children with COVID-19 were admitted to Renji Hospital, Shanghai Jiao Tong University School of Medicine (South Branch), a designated hospital for children with COVID-19. Among these patients, 568 (65.2%) were children under 3 years old, 870 (99.9%) were mild or moderate, and 1 was severe. This article reports the experience in the management of pediatric cases in this designated hospital, which included the following aspects: establishing an optimal case-admission process; strengthening multidisciplinary standardized diagnosis and treatment; optimizing the management, warning, and rescue system for severe COVID-19; implementing family-centered nursing care; formulating an individualized traditional Chinese medicine treatment regimen; optimizing the discharge process and strengthening bed turnover; implementing strict whole-process control to reduce the risk of nosocomial infection; constructing a structured medical record system and using information platforms to adapt to the work mode of large-volume cases; conducting scientific research and sharing the experience in diagnosis and treatment.

Early severity prediction of BPD for premature infants from chest X-ray images using deep learning: A study at the 28th day of oxygen inhalation.

BACKGROUND AND OBJECTIVE: Bronchopulmonary dysplasia is a common respiratory disease in premature infants. The severity is diagnosed at the 56th day after birth or discharge by analyzing the clinical indicators, which may cause the delay of the best treatment opportunity. Thus, we proposed a deep learning-based method using chest X-ray images of the 28th day of oxygen inhalation for the early severity prediction of bronchopulmonary dysplasia in clinic. METHODS: We first adopted a two-step lung field extraction method by combining digital image processing and human-computer interaction to form the one-to-one corresponding image and label. The designed XSEG-Net model was then trained for segmenting the chest X-ray images, with the results being used for the analysis of heart development and clinical severity. Therein, Six-Point cardiothoracic ratio measurement algorithm based on corner detection was designed for the analysis of heart development; and the transfer learning of deep convolutional neural network models were used for the early prediction of clinical severities. RESULTS: The dice and cross-entropy loss value of the training of XSEG-Net network reached 0.9794 and 0.0146. The dice, volumetric overlap error, relative volume difference, precision, and recall were used to evaluate the trained model in testing set with the result being 98.43 ± 0.39%, 0.49 ± 0.35%, 0.49 ± 0.35%, 98.67 ± 0.40%, and 98.20 ± 0.47%, respectively. The errors between the Six-Point cardiothoracic ratio measurement method and the gold standard were 0.0122 ± 0.0084. The deep convolutional neural network model based on VGGNet had the promising prediction performance, with the accuracy, precision, sensitivity, specificity, and F1 score reaching 95.58 ± 0.48%, 95.61 ± 0.55%, 95.67 ± 0.44%, 96.98 ± 0.42%, and 95.61±0.48%, respectively. CONCLUSIONS: These experimental results of the proposed methods in lung field segmentation, cardiothoracic ratio measurement and clinic severity prediction were better than previous methods, which proved that this method had great potential for clinical application.

The feasibility, safety, and efficacy of Paxlovid treatment in SARS-CoV-2-infected children aged 6-14 years: a cohort study.

Background: Paxlovid is recognized as an effective medication in preventing the progression of coronavirus disease of 2019 (COVID-19) to severe form in adults; however, its efficacy has remained unknown in pediatric cases. This study aimed to analyze the feasibility, safety, and efficacy of Paxlovid treatment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected children aged 6-14 years. Methods: We conducted a cohort study based on prospectively collected clinical data. We recruited 5 pediatric cases with underlying diseases treated with Paxlovid from 7 April 2022 to 26 May 2022 and 30 age-matched patients with underlying diseases who were not treated with Paxlovid as controls. The safety and efficacy of Paxlovid were primarily assessed by inter-group comparisons. Results: Of the 5 Paxlovid-treated cases, including 1 male and 4 females, 3 and 2 cases were mildly and moderately ill, respectively. The underlying diseases included congenital heart defects, cerebral palsy, Down syndrome, and leukemia. Only 1 patient had received 1 dose of an inactivated SARS-CoV-2 vaccine. Paxlovid was initiated within 5 days after the onset of symptoms in all cases. Comedications were used in 2 cases. In the safety analyses, after Paxlovid initiation, 1 patient had transient diarrhea, and 1 patient had transiently elevated liver enzymes [alanine transaminase (ALT), 125 U/L; aspartate transaminase (AST), 83 U/L; normal range, <40 U/L]. In the efficacy analyses, all 5 Paxlovid-treated cases recovered, with the respective viral shedding times of 11, 4, 10, 9, and 9 days. Compared with age-matched controls, the viral shedding times were not significantly different between groups. Conclusions: Based on the current small sample size study, Paxlovid is a feasible option for treating SARS-CoV-2-infected children aged 6-14 years with underlying diseases. However, the safety and efficacy of Paxlovid warrant further large-scale studies.

Steep Decline in Binding Capability of SARS-CoV-2 Omicron Variant (B.1.1.529) RBD to the Antibodies in Early COVID-19 Convalescent Sera and Inactivated Vaccine Sera.

A new SARS-CoV-2 variant B.1.1.529 was named by the WHO as Omicron and classified as a Variant of Concern (VOC) on 26 November 2021. Because this variant has more than 50 mutations, including 30 mutations on the spike, it has generated a lot of concerns on the potential impacts of the VOC on COVID-19. Here through ELISA assays using the recombinant RBD proteins with sequences the same to that of SARS-CoV-2 WIV04 (lineage B.1), the Delta variant and the Omicron variant as the coating antigens, the binding capabilities between the RBDs and the antibodies in COVID-19 convalescent sera and vaccine sera after two doses of the inactivated vaccine produced by Sinopharm WIBP are compared with each other. The results showed that the Omicron variant may evade antibodies induced by the ancestral strain and by the inactivated vaccine, with significant reduction in the binding capability of its RBD much greater than that of the Delta variant.