[The association between baseline TPOAb and/or TgAb positivity and thyroid immune-related adverse events in patients with malignancies following treatment with immune checkpoint inhibitors].

Objective: To investigate the association between positive anti-thyroid peroxidase antibody (TPOAb) and/or anti-thyroglobulin antibody (TgAb) and the occurrence of thyroid immune-related adverse events (irAEs) in patients with malignant tumors who treated with immune checkpoint inhibitors (ICIs). Methods: A case-control study. A total of 116 patients with malignant tumor who received ICIs treatment and underwent thyroid function evaluation at Peking Union Medical College Hospital from January 2017 to April 2023 were enrolled retrospectively, including 77 males and 39 females, with a median age of (M(Q1, Q3)) 63.0 (55.0, 70.0) years. The patients were divided into the euthyroid group (n=58) and the thyroid irAEs group (n=58) according to whether thyroid irAEs occurred after ICIs treatment. The clinical characteristics and baseline anti-thyroid antibodies associated with the occurrence of thyroid irAEs after ICIs treatment in patients with malignant tumors were evaluated. Variables with statistical significance in univariate analysis were included in multivariate logistic regression model to analyze the risk factors for thyroid irAEs in patients with malignant tumors who received ICIs treatment. Results: In irAEs group, therewore 4 (3.4%) cases of clinical thyrotoxicosis, 23(19.8%) cases of subclinical thyrotoxicosis, 23 (19.8%) cases of clinical hypothyroidism, and 8(6.9%) cases of subclinical hypothyroidism. The positive rate of anti-thyroid antibodies at baseline in the thyrioid irAEs group was higher than that in the euthyroid group［16/58（27.6%）vs 3/58（5.2%），P=0.001］. After at least one course of ICIs treatment, the incidence of thyroid irAEs in patients with positive anti-thyroid antibodies at baseline was 84.2% (16/19), whereas it was 43.3% (42/97) in patients with negative anti-thyroid antibodies(P=0.001). Univariate logistic regression analysis showed that gender (OR=2.812, 95%CI:1.257-6.293), baseline thyroid autoantibodies were positive (OR=6.984, 95%CI: 1.909-25.547), baseline TgAb positivity (OR=8.909, 95%CI: 1.923-41.280), and baseline TPOAb positivity (OR=7.304, 95%CI: 1.555-34.308) were associated with thyroid irAEs (all P<0.05). Multivariate logistic regression analysis indicated that baseline TgAb positivity (OR=7.637, 95%CI: 1.617-36.072) was a risk factor for thyroid irAEs (P=0.01). Conclusions: The incidence of thyroid irAEs is higher in patients who are positive for baseline TPOAb and/or TgAb compared to those who are negative for TPOAb and TgAb. Patients with positive TgAb at baseline are at high risk of developing thyroid irAEs.

[Chinese expert guidance on overall application of lenvatinib in hepatocellular carcinoma].

Lenvatinib mesylate is an oral receptor tyrosine kinase inhibitor against targets of vascular endothelial growth factor receptors 1-3, fibroblast growth factor receptors 1-4, platelet-derived growth factor receptor α, stem cell growth factor receptor, and rearranged during transfection, et al. Lenvatinib has been approved by the National Medical Products Administration of China on September 4, 2018, for the first-line treatment of patients with unresectable hepatocellular carcinoma who have not received systematic treatment before. Up to February 2023, Lenvatinib has been listed in China for more than 4 years, accumulating a series of post-marketing clinical research evidences. Based on the clinical practice before and after the launch of lenvatinib and referring to the clinical experience of other anti-angiogenesis inhibitors, domestic multidisciplinary experts and scholars adopt the Delphi method to formulate the Chinese Expert Guidance on Overall Application of Lenvatinib in Hepatocellular Carcinoma after repeated discussions and revisions, in order to provide reference for reasonable and effective clinical application of lenvatinib for clinicians.

[Application of augmented reality navigation in laparoscopic and robot-assisted liver surgery].

In recent years, laparoscopic surgery and robotic surgery have been widely used, and various intraoperative image navigation systems have also developed rapidly. However, the liver itself has a complex vessel and duct system, which increase the difficulty of liver surgery. The augmented reality image navigation system combines the three-dimensional reconstructed image of the liver with the real liver anatomy, which presents the specific relationship between the tumor location and the surrounding vessels for the surgeon. Compared with other intraoperative image navigation methods, augmented reality has its unique advantages. This paper provides an overview of current advances in registration technology in augmented reality image navigation system, and focuses on its applications in liver surgery, including laparoscopic surgery and robotic surgery. Finally, the technological problems and difficulties still faced at present are summarized, and future directions worth studying in this field are proposed.

[Investigation on influenza vaccination policy and vaccination situation during the influenza seasons of 2020-2021 and 2021-2022 in China].

Objective: To investigate the policies and coverage of influenza vaccine during the influenza epidemic seasons of 2020-2021 and 2021-2022 in China. Methods: The national influenza vaccination policy and vaccination rate were investigated in counties and districts and described in the two epidemic seasons. Results: In the epidemic seasons of 2020-2021 and 2021-2022, the vaccination coverage of influenza in China was 3.16% and 2.47%, respectively. The free vaccination policy had the highest vaccination coverage (51.75% and 38.32%), followed by the medical insurance reimbursement policy (9.74% and 7.36%). During the epidemic season of 2021-2022, the number of counties and districts implementing the free vaccination policy in China decreased 61 compared with the previous year, but the number of people covered increased by 51.29%. However, the vaccination coverage of the vast population decreased significantly, with the medical staff (75.69% and 40.15% for two epidemic seasons), preschool children (58.86% and 26.15%), and the elderly (45.71% and 32.94%). During the epidemic season of 2021-2022, the number of counties and districts implementing the medical insurance reimbursement policy increased by 6 compared with the previous year, and the number of people covered increased by 11.12%, but the vaccination coverage decreased. Conclusion: The influenza vaccination rate in China is low, and the implementation of cost preferential policy can greatly improve the influenza vaccination rate.

[Thoughts and suggestions on co-administration of seasonal influenza vaccine and COVID-19 vaccine].

In the context of the global pandemic of COVID-19, the epidemic intensity, epidemic characteristics and infection risk of influenza have presented new features. COVID-19 and influenza have simultaneously emerged in many regions of the world. COVID-19 and influenza are similar in terms of transmission mode, clinical symptoms and other aspects. There are also similarities in the mechanism of influenza virus and novel coronavirus on cells. At the same time, it is feasible and significant to do a good job in the prevention and control of COVID-19 and influenza. This paper discusses the relevant strategies and measures for the joint prevention and control of influenza and novel coronavirus from the aspects of influenza vaccination to prevent co-infection, simultaneous vaccination of influenza vaccine and novel coronavirus vaccine, etc., and puts forward corresponding thoughts and suggestions, in order to provide scientific support for the formulation of strategies on seasonal influenza vaccine and novel coronavirus vaccination.

[Application of penile index in the diagnosis and therapeutic evaluation of concealed penis in children].

Objective: To explore the significance of penile index in the diagnosis of concealed penis and the evaluation of therapeutic efficacy. Methods: A retrospective study was conducted on 221 children with phimosis and 113 children with concealed penis aged 6-10, all of whom had undergone circumcision or phalloplasty respectively in Shanghai Children's Medical Center from January 2014 to December 2017. Penile index was measured before and after surgery. The values of phimosis and concealed penis were tested by group t test. Self -control test was performed for values of concealed penis before and after operations. Results: Penile index was 0.78±0.08 in children with phimosis. It was 0.23±0.10 in concealed penis before operation and changed to 0.84±0.11 postoperatively. In children with phimosis and concealed penile, the difference of penile index was statistically significant (P<0.001). The difference of penile index before and after operation was statistically significant (P<0.001) in children with concealed penis. Conclusion: Penile index is an effective index to evaluate the degree of penis exposure.

[Pilot surveillance and evaluation of influenza-like illness based on automatic computer analysis of electronic medical record in sentinel hospital].

Objective: To compare the accuracy of influenza-like illness (ILI) surveillance by automatic computer analysis based on electronic medical records and by doctor's report. Methods: A total of 3 542 patients who presented to Yichang Central Hospital fever clinic, respiratory department or emergency department between April to October 2019 with an ICD-10 code for acute respiratory illness (J00-J22) and complete electronic medical information of ILI related syndromes were drawn as the study sample. Taking the classification of the study sample according to the ILI case definition by influenza surveillance professionals as the gold standard, draw the receiver operating characteristic (ROC) curve and calculate sensitivity, specificity, diagnostic consistency to compared the accuracy of ILI surveillance by automatic computer analysis and by doctor's report. Results: Median age of 3 542 cases was 30 (24, 38) years old; 1 179 cases (33.29%) compliance with the case definition, ILI reported by doctors was 1 306 cases (36.87%), and computer automatic identification ILI were 1 150 cases (32.47%); 1 391 (39.27%) cases were men. The results of automatic computer analysis and doctor report consistency of kappa values with gold standard judgment were 0.97 and 0.66 respectively; area under the ROC curve was 0.98 and 0.84, respectively. And the sensitivity and specificity of automatic computer analysis were higher than that of doctor's report (all P values were <0.001), the sensitivity was 96.95% and 82.27%, and the specificity was 99.70% and 85.78%, respectively. Conclusion: The automatic computer analysis based on electronic medical records can identified ILI cases with good sensitivity and specificity in ILI case surveillance.

[The surgical treatment of ovarian cancer metastasis between liver and diaphragm: a report of 83 cases].

Objective: To explore the safety and feasibility of associating diaphragm resection and liver-diaphragmatic metastasis lesions resection for patients with advanced ovarian cancer. Methods: Retrospectively analysis 83 cases(98 times) of advanced ovarian cancer with liver-diaphragmatic metastasis between January 2012 and December 2016 at Department of Liver Surgery, Peking Union Medical College Hospital.The patients were aged from 19 to 75 years.Surgical procedure included metastatic lesions resection(43 times) and stripping(55 times). Operation status, post-operative complications, pathology results and follow-up of the patients were analyzed. Results: Fifteen patients received twice surgical treatment and 68 patients received one time surgical treatment. Postoperative hemorrhage in chest and between liver and diaphragm was not occurred in all cases.Dyspnea and low oxygen saturation were occurred in two cases of stripping patients and 1 case of metastatic lesions resection patients.Results of CT examination indicated that there was medium to large amount of ascites in right chests.The symptoms were relieved after placing thoracic closed drainage.Other patients were recovered smoothly.All patients were diagnosed as ovarian cancer by pathological examination. Conclusion: Associating diaphragm resection is safe and feasible for liver-diaphragmatic metastasis lesions from ovarian cancer.

[Theoretical models for influenza vaccination behavior at the individual level].

Influenza imposes a significant disease burden on society and individuals annually, and influenza vaccination is considered a significant public health measure to prevent influenza and reduce influenza-related severe disease and death. The low influenza vaccination rate in China is partly due to certain factors affecting the willingness and behavior of individuals to receive them. Scientific research and targeted interventions on these factors can effectively improve the vaccination situation. Commonly used individual-level theoretical models for influenza vaccination behavior include the health belief model, protection motivation theory, and theory of planned behavior. This study reviews theoretical models commonly employed in researching influenza vaccination willingness and behavior. An overview of these practical applications and challenges models is presented to provide references for relevant research and intervention programs in China.

[Progress in research of influenza vaccination in pregnant women].

Influenza is an acute respiratory infectious disease caused by influenza virus. Pregnancy is associated with physiologic and immunological changes that may increase the risk for influenza virus infection and influenza-related complications. Influenza vaccination is the most effective way to prevent influenza virus infection. WHO and many countries have classified pregnant women as a priority population for influenza vaccination, however, there are still many challenges for promoting influenza vaccination in pregnant women in China, influenza vaccination coverage in pregnant women remains low and some influenza vaccine package inserts list pregnancy as an absolute contraindication. In this paper, we summarize the research progress in the effects of influenza infection and influenza vaccination during pregnancy both at home and abroad, then discuss the strategies to promote influenza vaccination in pregnancy for the purpose of providing reference for the related research and policy development in China.

[Performance of screening of contacts of COVID-19 cases in same flight].

Objective: To understand the performance of 2019-nCoV nucleic acid detection in screening of contacts of COVID-19 cases in same flights and provide evidence for the effective screening of persons at high risk for the infection in domestic flights. Methods: The information of passengers who took same domestic flights with COVID-19 cases in China from April 1, 2020 to April 30, 2022 were retrospectively collected,and χ2 test was used to analyze positive nucleic acid detection rates in the passengers in different times before the onsets of the index cases, in different seat rows and in epidemic periods of different 2019-nCoV variants. Results: During the study period, a total of 433 index cases were identified among 23 548 passengers in 370 flights. Subsequently, 72 positive cases of 2019-nCoV nucleic acid were detected in the passengers, in whom 57 were accompanying persons of the index cases. Further analysis of the another 15 passengers who tested positive for the nucleic acid showed that 86.67% of them had onsets or positive detections within 3 days after the diagnosis of the index cases, and the boarding times were all within 4 days before the onsets of the index cases. The positive detection rate in the passengers who seated in first three rows before and after the index cases was 0.15% (95%CI: 0.08%-0.27%), significantly higher than in the passengers in other rows (0.04%, 95%CI: 0.02%-0.10%, P=0.007),and there was no significant difference in the positive detection rate among the passengers in each of the 3 rows before and after the index cases (P=0.577). No significant differences were found in the positive detection rate in the passengers, except the accompanying persons, among the epidemics caused by different 2019-nCoV variants (P=0.565). During the Omicron epidemic period, all the positive detections in the passengers, except the accompanying persons, were within 3 days before the onset of the index cases. Conclusions: The screening test of 2019-nCoV nucleic acid can be conducted in the passengers took the same flights within 4 days before the onsets of the index cases on board. Passengers who seated within 3 rows from the index cases can considered as the close contacts at high risk for 2019-nCoV, for whom screening should be conducted first and special managements are needed. The passengers in other rows can be classified as general risk persons for screening and management.

[Investigation of incidence of acute respiratory infection and healthcare-seeking behavior in period of COVID-19 epidemic].

Objective: To analyze the incidence of acute respiratory infection (ARI) and related healthcare seeking behaviors in population in the period of COVID-19 epidemic in China. Methods: According to the province specific cumulative incidence rates of COVID-19 reported as of March 31, 2020, the low, medium and high-risk areas were classified. In these areas, a stratified two stage cluster random sampling method was used to select participants for face-to-face questionnaire surveys. Data on the incidence of ARI and related healthcare seeking behaviors in community residents during COVID-19 epidemic period were collected to calculate the attack rate of ARI and related healthcare seeking rate. Logistic regression method was used to explore the influencing factors for ARI incidence and healthcare seeking behavior. Results: A total of 34 857 community residents were surveyed, in whom 647 (1.9%) reported that they had ARI symptoms during the COVID-19 epidemic period, and 241 (37.2%) had healthcare seeking behaviors. In terms of the incidence of COVID-19-related ARI, in high-risk area, the risk of COVID-19-related ARI was 1.36 times (95%CI: 1.12-1.65) than that in low-risk area; among different age groups, the risk of COVID-19-related ARI in age groups 20-39 years, ≥60 years was 1.80 times (95%CI: 1.29-2.59) and 1.63 times (95%CI: 1.14-2.40) than that in age group 1-9 years; the risk of COVID-19-related ARI in people with underlying diseases was 1.53 times (95%CI: 1.23-1.89) than that in those without underlying diseases; the risk of COVID-19-related ARI in people with contacts with confirmed cases of COVID-19 and people with fever or respiratory symptoms was 1.53 times (95%CI: 1.01-2.27) and 6.60 times (95%CI: 5.05-8.53) than those in people without these contacts. The healthcare seeking rate in COVID-19-related ARI patients with exposures to those with fever or respiratory symptoms was 1.68 times (95%CI: 1.05-2.70) than that in such patients without the exposures. Conclusions: The attack rate of COVID-19-related ARI was affected by the local epidemic level of COVID-19, and in high-risk area, the attack rate of COVID-19-related ARI was also high. The healthcare seeking rate in patients with COVID-19-related ARI was low. Therefore, it is necessary to encourage the healthcare seeking in people with ARI in COVID-19 pandemic period.

[Advance on the infectivity of SARS-CoV-2 infection at different stages].

The studies on infectiousness of person infected with SARS-CoV-2 at different stages of illness are an important basis for making effective prevention and control measures such as investigating the infectious source, determining the scope of close contacts and the timing of case isolation. This review discusses the infectiousness of cases infected with SARS-CoV-2 in the incubation period, symptomatic period and convalescent period by reviewing national and international literatures, technical and professional guidelines. Existing researches suggest that the infectious viruses could be isolated at the end of the incubation period as well as since illness onset, and viral load in upper respiratory tract swabs reached the peak on day 4-6 after illness onset and thereafter began to decline, implying the infectiousness was relatively strong at the end of incubation period and within one week after illness onset. Although there were a few cases who tested positive for SARS-CoV-2 after recovery, no evidence was found to indicate these cases can cause the transmission.

[Analysis on prevention and control of some infectious diseases in the elderly aged 60 years and above in China and countermeasure recommendation].

As the progress of population aging in China, the proportion of elderly population is increasing. Both chronic diseases and infectious diseases can threaten the health of the elderly. There are many kinds of infectious diseases, including vaccine preventable infectious diseases affecting the health of adults, such as influenza, pneumococcal diseases and herpes zoster. In addition, the newly emerged COVID-19 has caused a pandemic in the world, resulting the highest proportion of deaths occurred in the elderly and posing a serious threat to the health of the elderly. This paper mainly summarizes the prevention and control of vaccine preventable diseases and COVID-19 to which the elderly are susceptible, analyzes the infectious disease problems affecting the health of elderly population, and recommends countermeasures for the prevention and control of these diseases in elderly population.

[Distribution and infectious characteristics of re-positive cases infected with SARS-CoV-2].

Domestic and foreign literatures related to the persistence of SARS-CoV-2 and the re-positive cases infected with SARS-CoV-2 were reviewed, and the characteristics and infectivity of the re-positive cases were analyzed to provide scientific evidence for the improvement of case management and the development of measures to stop the spread of SARS-CoV-2. Existing studies have shown that re-positive rate of SARS-CoV-2 ranged from 2.4% to 19.8%, the median of interval between re-positive detection and discharge was 4-15 days. Following the second course of the disease, the anti-SARS-CoV-2 IgM, IgG and IgA positive rates of the cases were 11.11%-86.08%, 52.00%-100.00% and 61.54%-100.00% respectively, the total antibody and neutralizing antibody positive rates were 98.72% and 88.46%. The viral load of the re-positive cases was lower than that in the initial infection. At least 3 380 re-positive cases have been reported globally. SARS-CoV-2 strains were isolated from the samples of 3 re-positive cases (1 immunodeficiency case and 2 cases with abnormal pulmonary imaging). There were close contacts that were infected by an asymptomatic case taking immunosuppressive agents. In conclusion, the infectivity of re-positive cases infected with SARS-CoV-2 is generally very low. Rare re-positive cases infected with SARS-CoV-2 might cause further transmission. The management approach for the re-positive cases can be based on the assessment of the individual transmission risk according to the pathogen detection results.

[Progress in research of specific antibody dynamic characteristics in patients with COVID-19].

COVID-19 is an emerging infectious disease caused by SARS-CoV-2. After the infection of the virus, the host immune system is stimulated to produce multifarious specific antibodies to decrease or eliminate effects of the pathogen. Study of the specific antibodies dynamic characteristics in patients with COVID-19 is very important for the understanding and diagnosis of the disease, research and development of vaccine, and planning of prevention and control strategy. This paper reviews and summarizes the domestic and oversea research on dynamic characteristics of specific antibodies of COVID-19 patients, including the antibody producing, duration and level, and its possible influencing factors in order to improve the understanding of the immunological characteristics of COVID-19.

Structure/function analysis of a critical disulfide bond in the active site of L-xylulose reductase.

L-xylulose reductase (XR) is involved in water re-absorption and cellular osmoregulation. The crystal structure of human XR complemented with site-directed mutagenesis (Cys138Ala) indicated that the disulfide bond in the active site between Cys138 and Cys150 is unstable and may affect the reactivity of the enzyme. The effects of reducing agents on the activities of the wild-type and mutant enzymes indicated the reversibility of disulfide-bond formation, which resulted in three-fold decrease in catalytic efficiency. Furthermore, the addition of cysteine (>2 mM) inactivated human XR and was accompanied by a 10-fold decrease in catalytic efficiency. TOF-MS analysis of the inactivated enzyme showed the S-cysteinylation of Cys138 in the wild-type and Cys150 in the mutant enzymes. Thus, the action of human XR may be regulated by cellular redox conditions through reversible disulfide-bond formation and by S-cysteinylation.

Propofol alleviates hypoxic neuronal injury by inhibiting high levels of mitochondrial fusion and fission.

OBJECTIVE: This study aimed to explore the mechanism of propofol in alleviating neuronal oxidative damage. MATERIALS AND METHODS: The neuron cells were randomly assigned to normal group (NOR), model group (MOD), and propofol administration group (MED). A 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was carried out to detect the viability of neuron cells, reverse transcription PCR (RT-PCR) assay to determine the gene expression of Fis and Mfn1, and Western blot assay to determine the protein expression of Caspase-3, Caspase-9, Bax, Bcl-2, and COX-2. RESULTS: According to the results of cell proliferation rate, under normal circumstances, neuron cells would have some programmed death and weak apoptosis, while after hypoxia-reoxygenation, the apoptosis rate of neuron cells gradually increased with the increase of culture time, which was significantly higher than that of the NOR. After the addition of propofol, the overall apoptosis rate of neuron cells slowly increased, significantly lower than that in the MOD and close to that in the NOR. Compared with the NOR, the ROS content in the MOD was significantly reduced, and compared with the MOD, the ROS content in the MED significantly recovered. Furthermore, the RT-PCR results showed that compared with the NOR, the expression of mitochondrial fusion protein (Mfnl) in the MOD group declined significantly, and the expression of mitochondrial fission protein 1 (Fis1) increased significantly, while after the addition of propofol, the expression of Mfnl and Fis1 was closed to that in the NOR. WB results showed that compared with the NOR, the expression of apoptosis proteins (Caspase-3, Caspase-9, Bax, and COX-2) in the MOD increased significantly, and the expression of Bcl-2 reduced significantly (all p<0.05), and the addition of propofol improved the expression of corresponding proteins. CONCLUSIONS: Propofol could alleviate hypoxic neuronal injury by inhibiting high levels of mitochondrial fusion and fission.

Anatomical study of the anterior neurovascular interval approach to the elbow: observation of the neurovascular interval and relevant branches.

BACKGROUND: The aim of the study was to investigate the anatomy of the anterior nerve and artery of the elbow joint to provide reference on the relevant surgical approach to the elbow joint, and determine a simple better surgical approach for the treatment of part of the fractures of the elbow joint. MATERIALS AND METHODS: The upper extremities of 10 adult cadavers fixed by formaldehyde and perfused with red latex in the artery were observed to investigate the anatomic structure of the anterior approach to the elbow joint. From the clearance of the brachioradialis and pronator teres muscle to the approach of the neurovascular interval, we observed the states of the median nerve, the brachial, radial and ulnar arteries, and its branches through anatomical layers and measurement methods. RESULTS: Through the anterior neurovascular interval approach to the elbow, nerve and artery can be protected, and the anterior structures of the elbow, such as the ulna coronoid process, humeroulnar joint and trochlea of the humerus, can be exposed. CONCLUSIONS: This study demonstrates that the anterior anatomical structure of the elbow joint including the trochlea of the humerus, coronoid process of the ulna and the front capsule of the elbow can be exposed through the anterior neurovascular approach to the elbow.

[Analysis on seasonality, age distribution of influenza B cases and matching degree of influenza B vaccine in China, 2011-2019].

Objective: To analyze the seasonality, age distribution of influenza B cases and matching degree of influenza B vaccine in China from 2011 to 2019, and provide evidences for the future surveillance, estimation of disease burden of influenza B, application of quadrivalent vaccines, and development of vaccine strategies. Methods: The epidemiological and virological surveillance data of influenza B from week 14 of 2011 to week 13 of 2019 obtained from National Influenza Surveillance Network were used to draw hot spot maps and conduct descriptive statistics to analyze the seasonality and age distribution of influenza B cases. The published antigenicity analysis results from the China Weekly Influenza Report were used to analyze the matching degree between the trivalent vaccine strain and the circulating influenza B strains. Results: From 2011 to 2019, the incidence of influenza B showed obvious seasonal characteristics, and influenza B virus co-circulated with influenza A virus in six winter-spring seasons, and influenza B virus/Victoria and Yamagata lineages circulated alternately. In some southern provinces, two lineages co-circulated in some southern areas in certain years. The age distribution of influenza B cases was double-peaked, and both lineages had the highest positive rate in age-group 5-15 years, with peaks at age of 10 years; B/Victoria virus had a sub-peak in age-group 25-35 years; B/Yamagata virus had a sub-peak in age-group 55-65 years. Trivalent influenza vaccine strain and influenza B epidemic strains mismatched in 2015-2016 and 2017-2018 seasons, matched in 2011-2012, 2012-2013, 2013-2014, 2014-2015 and 2016-2017 seasons, and moderately matched in 2018-2019 season, but reactivity was low. Conclusions: Influenza B mainly occurred in winter-spring season in China, and its intensity was lower than that of influenza A. There was a difference in the age distribution of the cases among different virus strains. Trivalent influenza vaccine strains and influenza B epidemic strains mismatched in several seasons. It is crucial to conduct continuous surveillance of influenza B and disease burden evaluation, improve vaccine immunization strategy, increase influenza vaccination rate to reduce the harm of influenza B in high-risk groups.