[Epidemiological characteristics of imported COVID-19 cases in Beijing]

Objective: To analyze the epidemiological characteristics of imported COVID-19 cases and the effect of vaccination on virus load and disease severity of the cases in Beijing. Methods: The data of the imported COVID-19 cases in Beijing were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and Epidemiology investigation. The data were processed and analyzed by Excel 2010 and SPSS 22.0. Results: From June 1 to September 30, 2021, a total of 171 imported COVID-19 cases were reported in Beijing, of which 66.67% (114/171) were asymptomatic. The cases were mainly from the Philippines, the United Arab Emirates, the United Kingdom and the Russian Federation, accounting for 67.84% (116/171). The male to female ratio of the cases was 2∶1 (114∶57). The median age M (Q₁, Q₃) of the cases was 28 (23, 36) years. The cases of Chinese accounted for 80.12% (137/171). The sequencing of the whole genome of the virus in 47 imported COVID-19 cases showed that the proportion of Delta variant was 76.60% (36/47). The COVID-19 vaccination coverage rate in the cases was 60.82% (104/171), but the full vaccination coverage rate was 53.80% (92/171). In the imported COVID-19 cases, 13.53% (23/170) were screened to be SARS-CoV-2 nucleic acid positive on the day when they arrived in Beijing, and all the cases were positive for 2019-nCoV nucleic acid within 28 days. The severity of the disease was higher in the unvaccinated group than in the partially vaccinated group and fully vaccinated group (P<0.001). In the unvaccinated group, there were 1 severe case and 1 critical case. The median Ct values M (Q₁, Q₃) of N gene and ORFlab gene in unvaccinated group were 32.51 (23.23, 36.06) and 32.78 (24.00, 36.38), respectively. There was no significant difference in the median of double-gene Ct value between the partially vaccinated group and the fully vaccinated group. Conclusions: During the study period, most of the imported COVID-19 cases in Beijing were asymptomatic. No matter vaccinated or not, the viral loads in the COVID-19 cases were similar, but the vaccination could reduce the severity of the disease.

[Epidemiological characteristics of hand, foot and mouth disease among people aged 6 and over in Beijing, 2011-2020]

Objective: To analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) among people ≥6 years old in Beijing from 2011 to 2020. Methods: The incidence data of HFMD cases from 2011 to 2020 were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and the etiological surveillance of HFMD in 29 sentinel hospitals from 16 districts of Beijing. Descriptive epidemiological methods were used to analyze the distributions, pathogen constituents, and changes of HFMD cases in Beijing people ≥6 years old. Results: From 2011 to 2020, a total of 38 183 cases of HFMD were reported among people ≥6 years old in Beijing, of which 46 (0.12%) cases were severe. The average annual reported incidence was 19.04/100 000. The ratio of males to females were 1.37∶1(22 064∶16 119). The proportion of HFMD in people ≥6 years old increased from 7.56%(2 606/34 488) in 2011 to 24.54% (546/2 225) in 2020. The average incidence of HFMD was higher in Shunyi district, Yanqing district, and Tongzhou district than in other districts in Beijing. The positive rate of enterovirus in sentinel surveillance was 66.78% (1 976/2 959), the proportion of enterovirus group A 71 (EV-A71) was 45.29% (101/223) in 2014, no EV-A71 positive was detected in 2020, and the proportion of Coxsackievirus A 6 (CV-A6) increased from 15.11% (34/225) in 2016 to 81.08% (60/74) in 2020. Conclusions: From 2011 to 2020, the proportion of cases with HFMD in people ≥6 years old in Beijing increased yearly, and the proportion of EV-A71 positive patients decreased basically. Since 2016, CV-A6 has gradually become the dominant pathogen. More attention should be paid to the epidemic situation and dynamic pathogen changes of hand foot mouth disease in people ≥6 years old.

[Analysis on duplicated reporting of brucellosis in China, 2005-2017]

Objective: To analyze the current status of duplicated reporting of brucellosis in China during 2005-2017, to understand the impact of duplicated reporting on the incidence of brucellosis, analyze the possible causes of duplicated reporting, and put forward propose solutions to further improve the brucellosis surveillance data quality. Methods: Data were from brucellosis case reporting cards in National Notifiable Disease Report System (NNDRS), Excel 2010 software was used to establish the database, the duplicated reporting was identified by using Spark DataFrame aggregation analysis in Python 3.2. Results: During 2005-2017, a total of 499 577 cases of brucellosis were reported, but the duplicated reporting rate was 75.76/10 000 (3 785/499 577). The duplicated reporting rate in same year was 37.21/10 000 (1 859/499 577), the duplicated reporting rate in other year was 39.87/10 000 (1 992/499 577) and the overall duplicated reporting rate increased year by year. The duplicated reporting rate in same institution was 33.59% (1 271/3 785) and the duplicated reporting rate by other institutions was 66.41% (2 514/3 785). Hospitals had the highest number of duplicated reporting (2 757), and community healthcare centers had the highest of duplicated reporting rate (281.27/10 000) (123/4 373). The reported incidence of brucellosis was 2.926 4/100 000 in 2017, the corrected incidence was 2.844 8/100 000 after removing the duplicated reporting, which was the maximum decrease from 2005 to 2017, the corrected incidence decreased by 2.79%. From 2005 to 2017, the average reported incidence of brucellosis in Xinjiang Uygur autonomous region was 14.712 0/100 000, and the corrected incidence was 14.060 0/100 000 after removing the duplicate reporting, with a decrease by 4.43%, the biggest decline in China. The average reported incidence of brucellosis in Ningxia Hui autonomous region was 13.987 1/100 000, and the corrected incidence of brucellosis was 13.662 2/100 000, with a decrease of 2.32%, ranking second in China. The reasons for duplicated reporting of brucellosis included repeated medical care seeking in same or different medical institutions in same year or other year, including the repeated medical care seeking in other areas. Conclusions: During 2005-2017, the number of duplicated reporting of brucellosis cases was on the rise in China. Hospital and community health service centers had highest case number and rate of duplicate reporting respectively, the duplicated reporting was mainly caused by re-reporting by other institutions or in other years. The duplicated reporting of brucellosis had greatly affected the accuracy of surveillance data of brucellosis in some provinces, such as Xinjiang and Ningxia. It is recommended to further strengthen brucellosis reporting management, improve data quality of NNDRS.

Single-mode optical waveguides

An efficient and powerful technique has been developed to treat the problem of wave propagation along arbitrarily shaped single-mode dielectric waveguides with inhomogeneous index variations in the cross-sectional plane. This technique is based on a modified finite-element method. Illustrative examples were given for the following guides: (a) the triangular fiber guide; (b) the elliptical fiber guide; (c) the single material fiber guide; (d) the rectangular fiber guide; guide; (g) the optical stripline guide.