ObjectiveTo understand the seropositivity of neutralizing antibodies (NAb) and low-level NAb against SARS-CoV-2 infection in the community residents, and to explore the impact of COVID-19 vaccination and SARS-CoV-2 infection on the levels of NAb in human serum. MethodsOn the ground of surveillance cohort for acute infectious diseases in community populations in Shanghai, a proportional stratified sampling method was used to enroll the subjects at a 20% proportion for each age group (0‒14, 15‒24, 25‒59, and ≥60 years old). Blood samples collection and serum SARS-CoV-2 NAb concentration testing were conducted from March to April 2023. Low-level NAb were defined as below the 25^th percentile of NAb. ResultsA total of 2 230 participants were included, the positive rate of NAb was 97.58%, and the proportion of low-level NAb was 25.02% (558/2 230). Multivariate logistic regression analysis indicated that age, infection history and vaccination status were correlated with low-level NAb (all P<0.05). Individuals aged 60 years and above had the highest risk of low-level NAb. There was a statistically significant interaction between booster vaccination and one single infection (aOR=0.38, 95%CI: 0.19‒0.77). Compared to individuals without vaccination, among individuals infected with SARS-CoV-2 once, both primary immunization (aOR=0.23, 95%CI: 0.16‒0.35) and booster immunization (aOR=0.12, 95%CI: 0.08‒0.17) significantly reduced the risk of low-level NAb; among individuals without infections, only booster immunization (aOR=0.28, 95%CI: 0.14‒0.52) showed a negative correlation with the risk of low-level NAb. ConclusionsThe population aged 60 and above had the highest risk of low-level NAb. Regardless of infection history, a booster immunization could reduce the risk of low-level NAb. It is recommended that eligible individuals , especially the elderly, should get vaccinated in a timely manner to exert the protective role of NAb.

OBJECTIVES: We propose a new melanoma segmentation model, SG-UNet, to enhance the precision of melanoma segmentation in dermascopy images to facilitate early melanoma detection. METHODS: We utilized a U-shaped convolutional neural network, UNet, and made improvements to its backbone, skip connections, and downsampling pooling sections. In the backbone, with reference to the structure of VGG, we increased the number of convolutions from 10 to 13 in the downsampling part of UNet to achieve a deepened network hierarchy that allowed capture of more refined feature representations. To further enhance feature extraction and detail recognition, we replaced the traditional convolution the backbone section with self-calibrated convolution to enhance the model's ability to capture both spatial and channel dimensional features. In the pooling part, the original pooling layer was replaced by Haar wavelet downsampling to achieve more effective multi-scale feature fusion and reduce the spatial resolution of the feature map. The global attention mechanism was then incorporated into the skip connections at each layer to enhance the understanding of contextual information of the image. RESULTS: The experimental results showed that the SG-UNet model achieved significantly improved segmentation accuracy on ISIC 2017 and ISIC 2018 datasets as compared with other current state-of-the-art segmentation models, with Dice reached 92.41% and 86.62% and IoU reaching 92.31% and 86.48% on the two datasets, respectively. CONCLUSIONS The proposed model is capable of effective and accurate segmentation of melanoma from dermoscopy images.
Melanoma/diagnosis* ; Humans ; Neural Networks, Computer ; Dermoscopy/methods* ; Skin Neoplasms ; Image Processing, Computer-Assisted/methods* ; Calibration ; Algorithms

Objective　To establish a dual droplet digital PCR (ddPCR) assay for herpes simplex virus type I (HSV-1) and varicella-zoster virus (VZV). Methods The specific primers and probes were derived based on the conserved regions of HSV-1 and VZV genome. The primer-probe combinations were screened, and the annealing temperatures and primer-probe concentration ratios of the dual-droplet digital PCR reaction were optimized to establish a dual-droplet digital PCR reaction system for HSV-1 and VZV, which was tested for other viruses and validated for clinical samples. The sensitivity, specificity, and reproducibility of the established dual microtiter digital PCR method were analyzed. Results The optimal concentrations of primers and probes for the dual ddPCR detection method of HSV-I and VZV were determined to be 800 nmol/L and 250 nmol/L, respectively, with an optimal annealing temperature of 56 ℃. The correlation coefficient (R2) of the standard curve of the dual ddPCR assay was 0.99, showing a clear linear relationship. The method showed high sensitivity, with the lowest detection limit of herpes simplex virus type I being 2.97 copies/μL, and for VZV being 2.73 copies/μL. The repeatability was high with a small coefficient of variation and stable detection results; the specificity was excellent, and no cross-reaction was found with herpes simplex virus type Ⅱ, Epstein-Barr virus, Adenovirus, Coxsackievirus (CA6/CA10/CA16), Cytomegalovirus, Human Cytomegalovirus, Human enterovirus 71, Japanese Encephalitis virus, West Nile virus, Measles virus, Mumps virus, and human nucleic acids. Conclusions The dual droplet digital PCR assay for herpes simplex virus type I and varicella-zoster virus established in this experiment has strong sensitivity, specificity, and high repeatability, and can provide a solution for rapid quantitative detection of the two viruses in different scenarios.

Abstract: More than 300 mosquito-borne arboviruses have been found worldwide, among which Dengue virus, Chikungunya virus, Japanese encephalitis virus, West Nile virus, and Zika virus are circulating around the world, causing a huge public health burden and arousing widespread concern in the whole society. China's vast territory and complex geographical landscapes are suitable for the reproduction of various mosquito-borne arboviruses, so the species and geographical distribution of mosquito-borne arboviruses in China have attracted much attention. Since the 1980s, 38 mosquito-borne arboviruses belonging to nine families, including Flaviviridae, Bunyaviridae, Togaviridae, and Reoviridae, have been isolated and identified from more than 1 million mosquitoes and human and animal specimens collected across China by means of tissue cell culture and animal inoculation. The results of field and laboratory tests indicate the existence of various mosquito-borne arboviral diseases in China, including Japanese encephalitis, Dengue fever, West Nile encephalitis, and febrile diseases caused by Tahyna virus infection. This study summarizes the species and geographical distribution of mosquito-borne arboviruses, mosquito-borne arboviruses, and their vectors, and mosquito-borne arboviral infectious diseases in China, providing technical support for the control and prevention of mosquito-borne arbovirus and their corresponding diseases, endemic management, disease early warning and prediction. Joint prevention and control of arboviral diseases in Asia and even the world is also of long-term and practical significance.

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the efficacy of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects who were previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extended or switched TMF treatment for 48 weeks. Efficacy was evaluated based on virological, serological, biological parameters, and fibrosis staging. Statistical analysis was performed using the McNemar test, t-test, or Log-Rank test according to the data. Results:593 subjects from the initial TMF group and 287 subjects from the TDF group were included at week 144, with the proportions of HBV DNA<20 IU/ml at week 144 being 86.2% and 83.3%, respectively, and 78.1% and 73.8% in patients with baseline HBV DNA levels ≥8 log10 IU/ml. Resistance to tenofovir was not detected in both groups. For HBeAg loss and seroconversion rates, both groups showed a further increase from week 96 to 144 and the 3-year cumulative rates of HBeAg loss were about 35% in each group. However, HBsAg levels were less affected during 96 to 144 weeks. For patients switched from TDF to TMF, a substantial further increase in the alanine aminotransferase (ALT) normalization rate was observed (11.4%), along with improved FIB-4 scores.Conclusion:After 144 weeks of TMF treatment, CHB patients achieved high rates of virological, serological, and biochemical responses, as well as improved liver fibrosis outcomes. Also, switching to TMF resulted in significant benefits in ALT normalization rates (NCT03903796).

Objective:In chronic hepatitis B (CHB) patients with previous 96-week treatment with tenofovir amibufenamide (TMF) or tenofovir disoproxil fumarate (TDF), we investigated the safety profile of sequential TMF treatment from 96 to 144 weeks.Methods:Enrolled subjects that previously assigned (2:1) to receive either 25 mg TMF or 300 mg TDF with matching placebo for 96 weeks received extending or switching TMF treatment for 48 weeks. Safety profiles of kidney, bone, metabolism, body weight, and others were evaluated.Results:666 subjects from the initial TMF group and 336 subjects from TDF group with at least one dose of assigned treatment were included at week 144. The overall safety profile was favorable in each group and generally similar between extended or switched TMF treatments from week 96 to 144. In subjects switching from TDF to TMF, the non-indexed estimated glomerular filtration rate (by non-indexed CKD-EPI formula) and creatinine clearance (by Cockcroft-Gault formula) were both increased, which were (2.31±8.33) ml/min and (4.24±13.94) ml/min, respectively. These changes were also higher than those in subjects with extending TMF treatment [(0.91±8.06) ml/min and (1.30±13.94) ml/min]. Meanwhile, switching to TMF also led to an increase of the bone mineral density (BMD) by 0.75% in hip and 1.41% in spine. On the other side, a slight change in TC/HDL ratio by 0.16 (IQR: 0.00, 0.43) and an increase in body mass index (BMI) by (0.54±0.98) kg/m 2 were oberved with patients switched to TMF, which were significantly higher than that in TMF group. Conclusion:CHB patients receiving 144 weeks of TMF treatment showed favorable safety profile. After switching to TMF, the bone and renal safety was significantly improved in TDF group, though experienceing change in metabolic parameters and weight gain (NCT03903796).

Objective:To establish a rapid pipeline for whole genome sequencing of Chikungunya virus (CHIKV) by combining imbricated multiplex-PCR amplification and Illumina high-throughput sequencing platform.Methods:The primary reference sequences of CHIKV were downloaded from the National Center for Biotechnology Information (NCBI) database, covering all genotypes of CHIKV. After multiple alignments using the Mafft software and phylogenetic analysis, the 20 CHIKV references were selected for primer design. The Primal Scheme tool and Geneious Prime software were used to design, evaluate and optimize the primer panel. Finally, seven CHIKV-positive samples were involved in the validation of the primer panel.Results:All the amplicons of the designed panel were generated successfully. The consensuses generated from the mapping results could cover 100.00% of the coding region of the CHIKV genome when the Ct-value of the sample was less than 33, as the percentage would decrease to 99.38% when the Ct-value reached 35. The mapping percentage could be increased by 5.70%-25.43% when using the stepwise correction mapping strategy.Conclusion:The multiplex-PCR amplification method for CHIKV whole genome sequencing is relatively simple and convenient, which only requires two tubes of PCR amplification and performs well on CHIKV-positive clinical samples with different concentration levels of virus.

Objective:To analyze the growth characteristics of different genotypes of Japanese encephalitis virus (JEV) in different cell lines, and to provide scientific basis for the selection of cell lines in the study of JEV.Methods:BHK-21, Vero, C6/36, PK-15, DF-1, N2a, SH-sy5y and MDCK cell lines were selected. The proliferation ability of genotype 1 (NX1889 strain), genotype 3 (P3 strain) and genotype 5 (XZ0934 strain) JEV in these cell lines was evaluated by plaque assay and RT-qPCR.Results:Significant cytopathogenic effects (CPE) were observed in BHK-21, Vero, C6/36, DF-1, N2a and PK-15 cell lines across all three JEV genotypes. However, no significant differences in CPE characteristics were observed within the same cell line. SH-sy5y and MDCK cell lines did not show significant CPE, but virus proliferation was detected in SH-sy5y cell line, while MDCK cell line were found to be insensitive to JEV. No significant difference was observed in the proliferation curves of G1, G3 and G5 JEV in BHK-21, Vero and SH-sy5y cell lines. In C6/36 and PK-15 cell lines, the titer of G1 JEV was higher than that of G3 and G5. In DF-1 cell line, G5 demonstrated a higher titer than the other two genotypes, whereas in N2a cell line, G5 showed a lower titer than the other two.Conclusions:There are differences in the proliferation of three different genotypes of JEV in different cell lines, which can provide reference for the study of JEV in different directions.

Objective:To elucidate the etiological and epidemiological characteristics and epidemiological patterns of viral acute respiratory infections (ARI) in Shanghai during 2023, with the aim of providing robust laboratory evidence for effective prevention and control strategies against related respiratory diseases and facilitating risk assessment.Methods:Respiratory pathogens were detected in the clinical surveillance specimens submitted by sentinel hospitals through multiplex PCR, as part of the multi-pathogen surveillance of acute respiratory infections in Shanghai during 2023. The obtained detection result were statistically analyzed in conjunction with sample information.Results:The positive detection rate of viral pathogens in 2023 was 21.17% (984/4 648), with rates of 33.53% (504/1 503) observed in ILI cases and 15.62% (480/3 145) in SARI cases. Influenza A virus (FluA) was the predominant virus detected, accounting for 13.7% (637/4 648). Other viruses identified in the surveillance samples included influenza B virus (Flu B), human rhinovirus/enterovirus (HRV/HEV), respiratory syncytial virus (RSV), human metapneumovirus (HMPV), parainfluenza virus (PIV), adenovirus (ADV) and human bocavirus (HBoV). Regarding temporal distribution, HRV/HEV and RSV exhibited the highest detection rates during the second quarter at 2.27% each (28/1 236). PIV had its peak during the third quarter at a rate of 2.49% (35/1 405), and HMPV showed prevalence mainly during the third and fourth quarters, with detection rates of 2.63% (37/1 405) and 2.35% (32/1 360), respectively.Conclusions:In acute respiratory infection surveillance cases in Shanghai in 2023, Flu A emerged as the predominant respiratory pathogen. The detection rate of HMPV ranked second only to Flu A, while other respiratory viruses such as HRV/HEV, RSV, and PIV were detected during different seasons and co-circulated. The prevalence of various respiratory viruses varied among different infected populations and over times.

Objective:To establish a rapid pipeline for whole genome sequencing of Chikungunya virus (CHIKV) by combining imbricated multiplex-PCR amplification and Illumina high-throughput sequencing platform.Methods:The primary reference sequences of CHIKV were downloaded from the National Center for Biotechnology Information (NCBI) database, covering all genotypes of CHIKV. After multiple alignments using the Mafft software and phylogenetic analysis, the 20 CHIKV references were selected for primer design. The Primal Scheme tool and Geneious Prime software were used to design, evaluate and optimize the primer panel. Finally, seven CHIKV-positive samples were involved in the validation of the primer panel.Results:All the amplicons of the designed panel were generated successfully. The consensuses generated from the mapping results could cover 100.00% of the coding region of the CHIKV genome when the Ct-value of the sample was less than 33, as the percentage would decrease to 99.38% when the Ct-value reached 35. The mapping percentage could be increased by 5.70%-25.43% when using the stepwise correction mapping strategy.Conclusion:The multiplex-PCR amplification method for CHIKV whole genome sequencing is relatively simple and convenient, which only requires two tubes of PCR amplification and performs well on CHIKV-positive clinical samples with different concentration levels of virus.