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Objective@#To investigate the epidemiological characteristics of influenza in Yuhang District, Hangzhou City from 2019 to 2023, so as to provide the reference for formulating influenza prevention and control measures.@*Methods@#Influenza case data with current address in Yuhang District was collected through the Chinese Disease Prevention and Control Information System from 2019 to 2023. Influenza-like illness data was collected through the Hangzhou Epidemiological Investigation System. Time distribution, population distribution and pathogen detection of influenza-like illness were descriptively analyzed.@*Results@#There were 118 319 influenza cases reported in Yuhang District from 2019 to 2023, with an average annual reported incidence rate of 2 316.80/105. The highest incidence rate was seen in 2023, with a reported incidence rate of 5 736.82/105. The peak incidence of influenza occurred from November to March of the following year, presenting the winter and spring epidemic. The cases were mainly distributed in the age groups of 7 to 14 years and 25 to 59 years, with 31 310 and 34 470 cases, accounting for 26.46% and 29.13%, respectively. Influenza cases were reported in all 12 towns (streets) in Yuhang District, with the top two being Wuchang Street and Liangzhu Street, with the average annual incidence rates of 17 346.08/105 and 14 945.80/105, respectively. From 2019 to 2023, there were 103 868 cases of influenza-like illness, and 1 482 throat swab samples were collected. Among them, 260 positive samples of influenza virus were detected, with a positive rate of 17.54%. The peak detection period for positive specimens was from November to March of the following year, with 222 influenza virus positive specimens detected. The influenza virus types included H1N1, H3N2, and Victoria B, accounting for 25.77%, 38.85% and 35.38%, respectively.@*Conclusions@#The peak of influenza outbreak in Yuhang District from 2019 to 2023 was in winter and spring, with children and adolescents being the main affected objectives. H1N1, H3N2 and Victoria B were alternately prevalent. Prevention and control measures such as influenza vaccination should be strengthened.
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@#Abstract: Objective To analyze the clinical characteristics and changes of serum IgG, IgM antibodies in patients infected with the SARS-CoV-2 B.1.1.529 (Omicron) variant. Methods The clinical data of 82 patients with SARS-CoV-2 B.1.1.529 variant was analyzed retrospectively. Based on the presence of pneumonia on chest CT, the patients were divided into pneumonia group and non-pneumonia group. Serum IgG, IgM antibodies were observed at 5 time points T1 (1~<4 d), T2 (4~<8 d), T3 (8~<15 d), T4 (15~<22 d) and T5 (22~<30 d) after admission. Results Among the 82 patients infected with the SARS-CoV-2 B.1.1.529 variant strain, there were 62 cases of cough, 31 cases of fever, 33 cases of throat discomfort, 5 cases of muscle soreness and 3 cases of diarrhea. The serum IgG antibody levels at 5 time points were 50.22 (142.20) AU/mL, 326.50 (220.63) AU/mL, 368.23 (76.21) AU/mL, 368.65 (79) AU/mL, and 385.26 (113.10) AU/mL, respectively. The level of serum IgG antibody in the pneumonia group was lower than that of the non-pneumonia group at T1 and T4 time points, and the differences were statistically significant (P<0.05) , the positive rate of serum IgG antibody in the pneumonia group was lower than that of the non-pneumonia group at the T1 time point, and the difference was statistically significant (P<0.05) . The serum IgM antibody levels at 5 time points were 0.41 (0.81) AU/mL, 0.95 (1.62) AU/mL, 1.09 (2.42) AU/mL, 0.74 (3) AU/mL, and 0.81 (3.10) AU/mL respectively, and there was no significant difference between the two groups. Conclusion The clinical symptoms of patients infected with the SARS-CoV-2 B.1.1.529 variant strain are mild. Serum IgG antibodies increased after infection, but there are some differences between the pneumonia group and the non-pneumonia group, whether serum IgG has a protective effect needs further research; the serum IgM antibodies do not increase highly after infection, there are some differences between individuals.