Analysis of clinical characteristics of 66 pediatric patients with B.1.617.2 (Delta) variant of COVID-19.

BACKGROUND: The aim of this study was to analyze the clinical characteristics of 66 pediatric patients with B.1.617.2 (Delta) variant of coronavirus disease 2019 (COVID-19). METHODS: Sixty-six pediatric patients with B.1.617.2 (Delta) variant of COVID-19 admitted to the hospital from July to August 2021 were classified into mild (n = 41) and moderate groups (n = 25). Clinical characteristics, laboratory data and dynamic trends in different time periods were analyzed retrospectively. RESULTS: There were no statistically significant differences in age, gender ratios and clinical symptoms between the mild group and the moderate group. All the patients in the moderate group had clusters of onsets, and the incubation period was shorter than that of the mild group. Within 24 hours of admission, the levels of erythrocyte sedimentation rate, cardiac troponin I, D-dimer in the moderate group were higher than that in the mild group (P < 0.05). The titers of immunoglobulin (Ig) G and IgM antibodies gradually increased after disease onset. Thirty-five (53.03%) children were tested positive for antibodies in 4-12 days. IgG increased gradually, while IgM decreased obviously in about 15 days after disease onset. The cycle threshold values of open reading frame 1ab and nucleocapsid protein gene in the severe acute respiratory syndrome coronavirus 2 genomes increased gradually on the 3rd, 6th, 9th, and 12th days after disease onset, compared with those in day 0. CONCLUSIONS: The symptoms of children with B.1.617.2 (Delta) variant of COVID-19 were mild. The description and analysis of the clinical characteristics and laboratory data can help medical staff to evaluate the condition of children with COVID-19 and to accumulate more clinical experience.

Chest CT features of children infected by B.1.617.2 (Delta) variant of COVID-19.

BACKGROUND: This study aimed to explore the imaging characteristics, diversity and changing trend in CT scans of pediatric patients infected with Delta-variant strain by studying imaging features of children infected with Delta and comparing the results to those of children with original COVID-19. METHODS: A retrospective, comparative analysis of initial chest CT manifestations between 63 pediatric patients infected with Delta variant in 2021 and 23 pediatric patients with COVID-19 in 2020 was conducted. Corresponding imaging features were analyzed. In addition, the changing trend in imaging features of COVID-19 Delta-variant cases were explored by evaluating the initial and follow-up CT scans. RESULTS: Among 63 children with Delta-variant COVID-19 in 2021, 34 (53.9%) showed positive chest CT presentation; and their CT score (1.10 ± 1.41) was significantly lower than that in 2020 (2.56 ± 3.5) (P = 0.0073). Lesion distribution: lung lesions of Delta cases appear mainly in the lower lungs on both sides. Most children had single lobe involvement (18 cases, 52.9%), 14 (41.2%) in the right lung alone, and 14 (41.2%) in both lungs. A majority of Delta cases displayed initially ground glass (23 cases, 67.6%) and nodular shadows (13 cases, 38.2%) in the first CT scan, with few extrapulmonary manifestations. The 34 children with abnormal chest CT for the first time have a total of 92 chest CT examinations. These children showed a statistically significant difference between the 0-3 day group and the 4-7 day group (P = 0.0392) and a significant difference between the 4-7 day group and the more than 8 days group (P = 0.0003). CONCLUSIONS: The early manifestations of COVID-19 in children with abnormal imaging are mostly small subpleural nodular ground glass opacity. The changes on the Delta-variant COVID-19 chest CT were milder than the original strain. The lesions reached a peak on CT in 4-7 days and quickly improved and absorbed after a week. Dynamic CT re-examination can achieve a good prognosis.

Associations Between Short-Term Ambient Particulate Matter Exposure and The Risk of Severe COVID-19 (preprint)

Background: Previous studies have suggested the relation between outdoor air pollution and the onset risk of Corona Virus Disease 2019 (COVID-19). However, there is a lack of data related to the severity of the disease, especially in China. Methods We recruited a group of COVID-19 patients diagnosed in a recent large-scale outbreak caused by Delta variants in eastern China. We collected ambient air pollution data of the same period where the case occurred and applied a generalized linear model (GLM) to analyze the effects of short-term outdoor ambient particulate matter (PM) exposure on the risk of severe COVID-19. Results A total of 476 confirmed adult patients were recruited, of which 42 (8.82%) had a severe illness. With a unit increase in PM 10 , the risk of severe COVID-19 increased by 47.64% (95% confidence interval [CI]: 27.67, 70.73) at lag 0-14 days, 65.00% (95% CI: 35.18, 101.40) at lag 0-21 days, and 69.44% (95% CI: 37.03, 109.50) at lag 0-28 days, respectively. The association remained significant at lag 0-14 days or 0-28 days in the multi-pollutant models. With a unit increase in PM 2.5 , the risk of severe COVID-19 increased by 49.47% (95% CI: 19.61, 86.78) at lag 0-14 days, 97.61% (95% CI: 45.92, 167.60) at lag 0-21 days, and 120.27% (95% CI: 56.53, 209.98) at lag 0-28 days, respectively. The association remained significant at lag 0-21 days or 0-28 days in the multi-pollutant models. Conclusions Our results indicated that short-term exposure to outdoor PM was positively related to the risk of severe COVID-19, and reducing air pollution may contribute to the control of COVID-19.

Assessment and Management on the Risk of Glucocorticoid-Induced Osteonecrosis After COVID-19 (preprint)

Background: Coronavirus disease 2019 (COVID-19) is an emerging global medical challenge and glucocorticoids remain the most promising therapy. Osteonecrosis (ON) is a disease caused by reduced blood flow to bones in the joints, which will rapidly induce joint destroy. ON had been frequently identified among convalescent patients after Severe Acute Respiratory Syndrome (SARS). Considering the similarity of SARS and COVID-19 on their pathogen, clinical characteristics and therapeutic strategies, it is particularly worrying whether ON will be a common sequela among convalescent COVID-19 patient.Methods: This multi-strategy study integrating different research methods, such as meta-analysis, systematic review and cross-sectional investigation. At first, two meta-analyses were performed on the incidence of osteonecrosis among SARS patients and the clinical data of glucocorticoid exposure among COVID-19 patients. Then, a systematic review of low-dosage glucocorticoid associated osteonecrosis and a real-world cross-sectional investigation of glucocorticoid exposure of COVID-19 patients in China Wuhan were also provided. Moreover, the pathogenesis, diagnosis, prevention, and treatment options for osteonecrosis after COVID-19 infection were further described.Findings: Our meta-analysis showed that 32% of SARS patients had developed ON after receiving glucocorticoid treatment with high dose, and our system review also supported that low level glucocorticoid exposure may lead to the occurrence of ON. Similarly, 40% of COVID-19 patients had undergone glucocorticoid treatment according to our meta-analysis. The cross-sectional investigation in China Wuhan found that the average of cumulative glucocorticoid exposure level was 504 mg calculated by the dosage of methylprednisolone. Notably, a confirmed osteonecrosis case after COVID-19 was identified during our investigation. Preventive management of ON shall better start with regular clinical followup observation.Interpretation: Growing evidence of the glucocorticoid therapy for COVID-19 patients prompts us to put forward the risk-classification-based early screening and early prevention protocol of ON, which may be of clinical significance in favorable prognosis of this disease.Registration Details: PROSPERO, registration number CRD42020203536.Funding Information: This study was supported by the Special Project For COVID-19 Prevention and Management of Ministry of Education of China (2020-JYB-YJ-023), the National Key Research and Development Program of China (2019ZX09731-002) and the State Key Program of National Natural Science Foundation of China (82030122).Declaration of Interests: The authors declare no competing interests.Ethics Approval Statement: The protocol for the investigation study has been registered in the Chinese Clinical Trial Registry (ChiCTR), (URL: http://www.chictr.org.cn/showproj.aspx?proj=61769, No. ChiCTR2000038333). This study was approved by the Ethics Institutional Review Board of the Third Affiliated Hospital of Beijing University of Chinese Medicine (No. BZYSY-2020KYKTPJ-06), and informed consent was obtained from every participant patient.

PTP-MEG2 regulates quantal size and fusion pore opening through two distinct structural bases and substrates.

Tyrosine phosphorylation of secretion machinery proteins is a crucial regulatory mechanism for exocytosis. However, the participation of protein tyrosine phosphatases (PTPs) in different exocytosis stages has not been defined. Here we demonstrate that PTP-MEG2 controls multiple steps of catecholamine secretion. Biochemical and crystallographic analyses reveal key residues that govern the interaction between PTP-MEG2 and its substrate, a peptide containing the phosphorylated NSF-pY83 site, specify PTP-MEG2 substrate selectivity, and modulate the fusion of catecholamine-containing vesicles. Unexpectedly, delineation of PTP-MEG2 mutants along with the NSF binding interface reveals that PTP-MEG2 controls the fusion pore opening through NSF independent mechanisms. Utilizing bioinformatics search and biochemical and electrochemical screening approaches, we uncover that PTP-MEG2 regulates the opening and extension of the fusion pore by dephosphorylating the DYNAMIN2-pY125 and MUNC18-1-pY145 sites. Further structural and biochemical analyses confirmed the interaction of PTP-MEG2 with MUNC18-1-pY145 or DYNAMIN2-pY125 through a distinct structural basis compared with that of the NSF-pY83 site. Our studies thus provide mechanistic insights in complex exocytosis processes.

Compare the epidemiological and clinical features of imported and local COVID-19 cases in Hainan, China.

BACKGROUND: Effective management of imported cases is an important part of epidemic prevention and control. Hainan Province, China reported 168 coronavirus disease 2019 (COVID-19), including 112 imported cases on February 19, 2020, but successfully contained the epidemic within 1 month. We described the epidemiological and clinical characteristics of COVID-19 in Hainan and compared these features between imported and local cases to provide information for other international epidemic areas. METHODS: We included 91 patients (56 imported and 35 local cases) from two designated hospitals for COVID-19 in Haikou, China, from January 20 to February 19, 2020. Data on the demographic, epidemiological, clinical and laboratory characteristics were extracted from medical records. Patients were followed until April 21, 2020, and the levels of antibodies at the follow-ups were also analysed by the Wilcoxon matched-pairs signed ranks test. RESULTS: Of the 91 patients, 78 (85.7%) patients were diagnosed within the first three weeks after the first case was identified (Day 1: Jan 22, 2020), while the number of local cases started to increase during the third week. No new cases occurred after Day 29. Fever and cough were two main clinical manifestations. In total, 15 (16.5%) patients were severe, 14 (15.4%) had complicated infections, nine (9.9%) were admitted to the intensive care unit, and three died. The median duration of viral shedding in feces was longer than that in nasopharyngeal swabs (19 days vs 16 days, P = 0.007). Compared with local cases, imported cases were older and had a higher incidence of fever and concurrent infections. There was no difference in outcomes between the two groups. IgG was positive in 92.8% patients (77/83) in the follow-up at week 2 after discharge, while 88.4% patients (38/43) had a reduction in IgG levels in the follow-up at week 4 after discharge, and the median level was lower than that in the follow-up at week 2 (10.95 S/Cut Off (S/CO) vs 15.02 S/CO, P <  0.001). CONCLUSION: Imported cases were more severe than local cases but had similar prognoses. The level of IgG antibodies declined from week 6 to week 8 after onset. The short epidemic period in Hainan suggests that the epidemic could be quickly brought under control if proper timely measures were taken.

Epidemiological and clinical features of imported and local patients with coronavirus disease 2019 (COVID-19) in Hainan, China (preprint)

Background: Hainan Island, which is a popular tourist destination, received many imported cases of Coronavirus disease 2019 (COVID-19) but successfully contained the epidemic within one month. We described the epidemiological and clinical characteristics of COVID-19 in Hainan and compared these features between imported and local cases to provide information for other international epidemic areas. Methods: : We included 91 patients (56 imported and 35 local cases) from two designated hospitals for COVID-19 in Haikou, China, from January 20 to February 19, 2020. Data on the demographic, epidemiological, clinical and laboratory characteristics were extracted from medical records. Patients were followed until April 21, 2020, and the levels of antibodies at the follow-ups were also analyzed. Results: : Of the 91 patients, 78 (85.7%) patients were diagnosed within the first three weeks after the first case was identified (Day 1: Jan 22, 2020), while the number of local cases started to increase during the third week. No new cases occurred after Day 29. Fever and cough were two main clinical manifestations. In total, 15 (16.5%) patients were severe, 14 (15.4%) had complicated infections, nine (9.9%) were admitted to the ICU, and three died. The median duration of viral shedding in feces was longer than that in nasopharyngeal swabs (19 days vs 16 days, P =0.007). Compared with local cases, imported cases were older and had a higher incidence of fever and concurrent infections. There was no difference in outcomes between the two groups. IgG was positive in 92.8% patients (77/83) in the follow-up at week 2 after discharge, while 88.4% patients (38/43) had a reduction in IgG levels in the follow-up at week 4 after discharge, and the median level was lower than that in the follow-up at week 2 (10.95 S/CO vs 15.02 S/CO, P<0.001). Conclusion: Imported cases were more severe than local cases but had similar prognoses. The level of IgG antibodies declined from week 6 to week 8 after onset. The short epidemic period in Hainan suggests that the epidemic could be quickly brought under control if proper timely measures were taken.

Epidemiological and clinical features of imported and local patients with coronavirus disease 2019 (COVID-19) in Hainan, China (preprint)

Background Hainan Island, a popular tourist destination, had received many imported cases of Coronavirus disease 2019 (COVID-19), but successfully contained the epidemics in one month. We described epidemiological and clinical characteristics of COVID-19 in Hainan and compared these features between imported and local cases to provide information for other international epidemic areas. Methods We included 91 patients (56 imported and 35 local cases) from two designed hospitals for COVID-19 in Haikou, China, from January 20 to February 19, 2020. Data on demographic, epidemiological, clinical and laboratory characteristics were extracted from medical records. Results Of the 91 patients, 78 (85.7%) patients were diagnosed within the first three weeks after the first case identified (Day 1: Jan 22, 2020), while the number of local cases started to increase from the third week. No new cases occurred after Day 29. Fever and cough were two main clinical manifestations. 15 (16.5%) were severe, 14 (15.4%) had complicated infections, nine (9.9%) were admitted to ICU, and three died. Median duration of viral shedding in feces was longer than that in nasopharyngeal swabs (19 days vs 16 days, P =0.007). Compared with local cases, imported cases were older, have higher incidence of fever and concurrent infections. There was no difference in outcomes between the two groups. Conclusion Imported cases were more severe than local cases, but could have similar prognosis. The short epidemic period in Hainan suggests that the epidemics could be quickly brought under control if proper timely measures were taken.