Coronavirus disease 2019 (COVID-19) has become a global pandemic disease. SARS-CoV-2 variants have aroused great concern and are expected to continue spreading. Although many countries have promoted roll-out vaccination, the immune barrier has not yet been fully established, indicating that populations remain susceptible to infection. In this review, we summarize the literature on variants of concern and focus on the changes in their transmissibility, pathogenicity, and resistance to the immunity constructed by current vaccines. Furthermore, we analyzed relationships between variants and breakthrough infections, as well as the paradigm of new variants in countries with high vaccination rates. Terminating transmission, continuing to strengthen variant surveillance, and combining nonpharmaceutical intervention measures and vaccines are necessary to control these variants.
COVID-19/prevention & control* ; COVID-19 Vaccines ; Humans ; Pandemics/prevention & control* ; SARS-CoV-2

Objective:To explore the relationship between cardiac discomfort symptoms, fear of disease progress and post-traumatic stress disorder (PTSD) in patients with acute myocardial infarction(AMI) after discharge, and to clarify main intervention direction of PTSD in patients with AMI.Methods:Patients with AMI who were discharged from Tangshan Gongren Hospital between 1 month and 1 year were selected from November 2019 to November 2020.The cardiac discomfort symptoms scale, fear of progress questionnaire(FoP-Q-SF) and post-traumatic stress disorder self-rating scale(PTSD-SS) were used to investigate cardiac discomfort symptoms, fear of disease progress level and post-traumatic stress disorder status.Spearman rank correlation analysis was used to analyze the relationship between cardiac discomfort symptoms, fear of disease progress and post-traumatic stress disorder by SPSS 24.0 software. The mediating effect of fear of disease progress was analyzed by AMOS 24.0 software.Results:The PTSD score was (32.78±12.38) of patients with AMI discharged from hospital for 1 month to 1 year and the incidence of PTSD was 12.3%.Spearman correlation test showed cardiac discomfort symptoms and fear of disease progress were positively correlated with PTSD( r=0.530, 0.723, both P<0.01) and cardiac discomfort symptoms was positively correlated with fear of disease progress( r=0.518, P<0.01). Mediating effect test showed that fear of disease progress was a complete mediator between cardiac discomfort symptoms and PTSD. Conclusion:Cardiac discomfort symptoms can affect PTSD through a complete mediator of fear of disease progress.

Objective:To take a broad overview of the current allocation of diagnosis and treatment resources and management for patients with tuberculous meningitis (TBM) in 49 hospitals in China.Methods:A cross-sectional survey about TBM was carried out in 49 hospitals from 27 provinces across China, by means of electronic questionnaire.The electronic questionnaire was filled by doctors in charge of the departments where TBM patients were routinely admitted from September to December 2018. The availability of medical resources, diagnosis, evaluation, treatment and surveillance in these hospitals were analyzed from the questionnaire. The count data were expressed as percentage.Results:Among the 49 participating hospitals, 37(75.5%) hospitals had less than 50 admissions of suspected TBM per year. Less than 20 TBM patients were confirmed by etiological diagnosis per year in 42(85.7%) participating hospitals.The availability of conventional medical imaging including computed tomography (CT), magnetic resonance imaging (MRI), enhanced MRI, cerebral angiography and magnetic resonance angiography (MRA) were 100.00%(49/49), 95.92%(47/49), 91.84%(45/49), 61.22%(30/49) and 67.35%(33/49), respectively. The rate of access to classic etiological diagnostic methods including acid-fast bacilli smear, mycobacterial culture and T cell spot test of tuberculosis infection were 77.55%(38/49), 95.92%(47/49) and 83.67%(41/49), respectively. Rifampin (100.0%, 49/49), isoniazid (100.0%, 49/49), pyrazinamide (98.0%, 48/49) and ethambutol (95.9%, 47/49) were most commonly used in initial anti-tuberculosis treatment of non-severe patients with TBM. The course of anti-tuberculosis treatment was 18 months in 25(51.0%) hospitals, and 12 months in 17(34.7%) hospitals. Intrathecal glucocorticoid and isoniazid were used in 39(79.6%) hospitals. Dexamethasone was used as part of treatment in 24(49.0%) hospitals, and the duration of glucocorticoid was about two months in 28(57.1%) hospitals. As for hyponatremia, 32(65.3%) hospitals didn′t investigate the cause, and hypertonic saline (83.7%, 41/49) and oral rehydration salts (71.4%, 35/49) were considered as the most common treatment strategy. Lumbar puncture was most commonly used for intracranial pressure surveillance in 48(98.0%) hospitals.Conclusions:The TBM cases admitted to the investigation hospitals are characterized by scattered sources and few confirmed cases of etiology. There are obvious heterogeneities in the diagnosis and treatment of TBM and the management of complications.The standardized plan for diagnosis and treatment of TBM are needed to improve the management.

Objective: To investigate the epidemiological and clinical characteristics of 91 cases of dengue fever outbreak in Jiangxi Province in 2019, and to strengthen the management and prevention of dengue fever. Methods: The clinical data, laboratory results and etiology tests of 91 patients with dengue fever from the Ninth Hospital of Nanchang, Zhangshu People′s Hospital, Fengcheng People′s Hospital and Nanchang County People′s Hospital from July 31, 2019 to September 27, 2019 were retrospectively collected. The t test was used for continuous variables and chi-square test was used for categorical variables. Results: A total of 91 dengue fever patients were reviewed. The patients age ranged from 4 to 87 years old, and the majority were adult patients. Most patients were farmers and they all had mosquito-biting history. Local cases were the major source of this outbreak. The incubation time was (5.19±2.96) days. All patients had fever over 38 ℃. Thirty-eight (41.8%) patients developed rashes, mainly distributed on the limbs and trunk, and 15 patients (16.5%) developed myalgia and fatigue. The incidence of rashes in patients admitted in September was 15.9% (7/44), which was significantly lower than 68.1% (32/47) in July and August (χ²=25.262, P<0.01). The incidence of headache in patients admitted in September was 27.3%(12/44), which was significantly lower than 78.7% (37/47) in July and August (χ² =24.206, P<0.01). Among the 91 patients, 64 (70.3%) patients had white blood cell counts less than 4×10⁹/L, 14(15.4%) patients had platelet counts less than 50×10⁹/L. The positive rate of dengue non-structural protein 1 (NS1) antigen was 100.0%(37/37), the positive rates of dengue antibody IgM and IgG were 50.0%(11/22) and 13.6%(3/22), respectively. Among the 113 serum samples tested for dengue virus RNA, 106 were identified with dengue virus type-1 and two were dengue virus type-2. In 22 patients who received tests within 7 days, the positive rate of NS1 antigen was 100.0% (22/22), the IgM and IgG positive rates were 50.0%(11/22) and 13.6% (3/22), respectively, and 19 patients were infected with dengue type-1. Among the IgM antibody positive cases, the onset days before sampling was (5.09±1.64) days, longer than that of IgM antibody negative cases ((2.82±1.83) days), with statistical significance (t=3.063, P=0.007). The onset time before sampling in dengue virus RNA-positive group was (3.53±1.87) days, which was shorter than that of RNA-negative group ((6.67±0.58) days), and the difference was statistically significant (t=2.839, P=0.013). Conclusions The dengue fever outbreak cases in Jiangxi Province in 2019 have typical clinical manifestations of dengue fever. Using the NS1 antigen test, IgM and IgG antibody tests and real-time fluorescent quantitative polymerase chain reaction for dengue virus genotyping during early onset of the disease can assistant clinicians in clinical management, controlling infectious source and stopping disease transmission.

Objective: To analyze the survival time of people living with HIV/AIDS and related influencing factors in Sichuan province during 1991-2017. Methods: A retrospective cohort study was conducted to analyze the data of 143 988 HIV/AIDS cases. The data were collected from Chinese HIV/AIDS Comprehensive Information Management System. Life table method was used to calculate the survival proportion of the cases, and Cox proportion hazard regression model was used to identify the factors related with survival time. Results: Among 143 988 HIV/AIDS cases a total of 30 420 cases died of AIDS related diseases (21.1%) and the average survival time was 11.51 years (95%CI: 11.39-11.64). Multivariate Cox regression analysis showed that the influencing factors for the survival of HIV/AIDS cases were gender (male vs. female, HR=1.35, 95%CI: 1.32-1.40), education level (primary school or below vs. junior middle school: HR=1.15, 95%CI: 1.12-1.18), ethnic group (Han vs. other ethnic groups, HR=1.46, 95%CI: 1.41-1.52), occupation (farmer vs. other occupations: HR=1.26, 95%CI: 1.22-1.29), age (≥55 years old vs. 15-24 years old: HR=3.18, 95%CI: 3.02- 3.36), disease phase (AIDS vs. HIV infection: HR=1.44, 95%CI: 1.39-1.48), antiretroviral therapy (ART) (receiving ART vs. receiving no ART: HR=0.20, 95%CI: 0.19-0.20), and CD₄⁺T cell counts at diagnosis (>500 cells/μl vs.<200 cells/μl: HR=0.42, 95%CI: 0.40-0.45). Conclusions The average survival time of HIV/AIDS cases was 11.51 years in Sichuan during 1991- 2017. The risk factors for the survival of the cases were male, education level of primary school or below, Han ethnic group, farmer, old age at diagnosis, disease phase, The protective factors for the survival of HIV/AIDS cases were receiving ART and higher CD₄⁺ T cell counts at diagnosis.

Objective To compare the detection performance of the modified serum test (TRUST) method and the traditional method in syphilis screening.Methods A series of TRUST high titer syphilis serum was diluted,and the positive rate of each method was calculated by using the improved method and the traditional method.Comparison of two detection methods of C50,C5 ～ C95 interval,as well as the accuracy of the density curve,and the consistency of the two methods were compared,and diagnostic performance were compared.Results The improved method of C50 was less than the traditional method of C50,and the improved method of C5 ～ C95 range was narrower than the traditional method,compared with the traditional method.The improved method of the non precision density curve was steeper than the traditional method,and the two confidence interval of the consistency degree of the 95％ methods was 73.4％ to 95.8％.The diagnostic sensitivity (SEN),diagnostic specificity (SPE),positive predictive value (PPV),negative predictive value (NPV) and diagnostic efficiency(DF) of the improved method were 64.29 ％,99.1％,85.71％,97.05 ％ and 96.39 ％,respectively.The SEN,SPE,PPV,NPV and DF of the traditional methods were 3.75 ％,98.49 ％,75 ％,96.18 ％ and 95 ％,respectively.The improved method was superior to the traditional methods in the two aspects of SEN and PPV (x2 =8.25,10.03,all P＜0.05),with the statistically significant difference.The improved method was slightly higher than the traditional method in SPE,NPV and DF (x2 =2.39,3.45,4.03,all P＞0.05),with the no statistically significant difference.Conclusion The precision,diagnostic sensitivity and diagnostic specificity of the improved method was higher than that of the traditional method,and it can be applied to the detection of large batch samples with the aid of the full automatic enzyme immunoassay instrument.The improved method can be used to replace the traditional method for syphilis screening.

Objective To investigate the value of ultrasonic direct signs and indirect signs in diagnosis of rotator cuff tears (RCTs).Methods Fifty-two patients underwent ultrasonography before arthroscopy were enrolled.The efficacy of ultrasonic direct and indirect signs in diagnosis of RCTs was calculated,and the accuracy of ultrasonic direct signs in diagnosis of subtypes for RCTs was compared with arthroscopic results.Results The accuracy of ultrasonic direct signs in diagnosis of the presence of tears,full-thickness tears and partial-thickness tears was 90.38％ (47/52),96.15％ (50/52)and 86.54％ (45/52),respectively.Additionally,the consistency of ultrasonic direct signs in diagnosis of subtypes for RCTs with arthroscopic results was good.With regard to ultrasonic indirect signs,the specificity of effusions including all subacromial/subdeltoid bursa effusions,intra-articular fluid and biceps tendon sheath effusions,subdeltoid bursa hernia and cartilage demarcation sign was 80.95％(17/21),90.48％ (19/21) and 95.24％ (20/21),respectively.Conclusion Ultrasonic direct signs combined with indirect signs have high clinical value in diagnosis of subtypes for RCTs.

Objective To explore the effect of low intensity ultrasound (LUS) and microbubble enhanced ultrasound cavitation (MEUS), alone or in combination, on ethanol ablation (EA) of rabbit liver and observe the changes of liver perfusion and liver function. Methods Sixty-two healthy New Zealand rabbits were randomized to five groups: LUS group (n=6), EA group (n=14), LUS + EA group (n=14), MEUS + EA group (n=14), MEUS + LUS + EA group (n=14). For LUS, pulsed low intensity focused ultrasound emission was adopted (focal distance, 15 cm; duty cycle, 0.036%-0.22%;therapy duration, 5-6 min). According to the experiment design, surgically exposed left lobe of the liver was treated. In the LUS, MEUS + EA, and MEUS + LUS + EA groups, quantitative parameters were calculated and compared between the experimental and control liver lobes after different treatments. Three rabbits in each of the EA, LUS + EA, MEUS + EA, and MEUS + LUS + EA groups were used to detect the contents of alanine aminotransferase (ALT) and aspartate transaminase (AST) in arterial blood at five different time points (before treatment, 1 h, 48 h, 5 d, and 7 d after treatment). The livers of the remaining rabbits were harvested for measurement of ethanol ablation volume by drainage method or examination of the histological changes by HE staining 48 h after treatment. Results In the LUS group, the peak intensity (PI) and the area under the curve (AUC) were higher in the experiment lobe than in the control lobe, but there was no significant difference. In the MEUS + EA and MEUS+LUS+EA groups, the PI and AUC values were significantly lower in the experiment lobe than in the control lobe(PI:51.65±16.90 vs 101.09±14.41,44.08±8.46 vs 113.40±9.35;AUC:2183.06±501.13 vs 4258.54±841.21,1900.39±352.59 vs 4385.55±1198.16;t=9.059,16.835,9.630,7.932,P<0.001 for all). In the LUS group, no necrosis was observed, and the necrosis volume was 0 ml. The necrosis volumes caused by ethanol ablation in the EA, LUS+EA, MEUS+EA, and MEUS+LUS+EA groups were (0.84±0.27) ml, (2.42±1.11) ml, (3.52±1.34) ml, and (4.01±1.45) ml. The ethanol ablation volume was significantly lower in the EA group than in the other three groups (u=-13.800, -20.400, -23.400, P<0.05 for all),although there were no significant difference between any two of the latter three groups. No pathological changes were observed in the ultrasound exposed liver of the LUS group. In contrast, a wide range of coagulation necrosis area was noted in the other four groups. Compared with pre-treatment values, ALT and AST levels in all groups showed a slight rise after treatment, peaked at 48 h, and gradually returned to the pretreatment levels after seven days. The tendency of changes in ALT and AST levels with time was similar among the four groups (F=0.256, P=0.855; F=0.517, P=0.686). Conclusion LUS and MEUS, alone or in combination, could significantly increase the ethanol ablated volume of rabbit liver without aggravating liver function.

Objective To explore experiences of patients with chronic obstructive pulmonary disease (COPD) to take up the home- based resistance training. Methods Twenty- two patients with COPD who completed the 12 weeks home- based resistance training were interviewed deeply, the phenomenological analysis method was used. Results Though reading, analysis, reflection, separation, theme refining, two themes were drawn: self- perceived benefits; pyhcological, social and healthy status barriers on taking up and persisting in the exercises. Conclusions The study finds that self- perceived benefits, psychological changes and confusion in COPD patients during home- based resistance training.As the medical staff, to seize the COPD patients for the purpose of health to do the health education and strengthen the relevant training, to help the patient perceive benefits on resistance training, to enhance the confidence of participating in the pulmonary rehabilitation, to promote the behavior change. Additionally, we should identify obstacles early and take up the intervention, to stimulate the enthusiasm of home- based resistance training in patients with COPD.

Objective To investigate the clinical value of high frequency ultrasound in discovering secondary pathological changes in infant with developmental dysplasia of the hip (DDH).Methods Thirtyfour infants with 36 dislocation hips were involved.Among them,32 were with unilateral dislocation of hip joint,2 were with bilateral dislocation of hip joint.High frequency ultrasound were used to observe the morphological changes of hip glenoid labrum,adipose hyperplasia in acetabulum,thickness variation of articular capsule,and development of the ossification center of the femoral head.Besides,the morphological changes of hip glenoid labrum and adipose hyperplasia in acetabul were compared with those from MRI.Results The sensitivity and specificity of ultrasound in diagnosing glenoid labral introversion were 82 ％ and 100％ respectively.The coincidence rate of diagnosing glenoid labral introversion and glenoid labral extroversion were both 83％.Adipose hyperplasias in acetabul were clearly seen in 31 hips using ultrasound.The thickness of articular capsule in the affected hip and in the healthy hip was (2.8 ± 0.6)mm versus (1.7 ± 0.4) mm,and the difference was obviously significant (P ＜0.01).The ossification center of the femoral head in the 34 infants were classified as the following four types:① which was smaller in the affected side than in the healthy side (22/34);②which was shown in the healthy side (7/34) but not in the affected side;③ which in both sides were not shown (4/34);④ which in both sides were small (1/34).Conclusions Ultrasound is a method of simple,rapid,non-invasive in diagnosing DDH,and it can be used to discover secondary pathological changes in infant with DDH,which provide important reference for clinical diagnosis and treatment.