Analysis on infection sources and transmission chains of three outbreaks caused by 2019-nCoV Omicron variant in Beijing, China / 中华流行病学杂志

Objective: To investigate the infection sources and the transmission chains of three outbreaks caused by 2019-nCoV Omicron variant possibly spread through cross-border logistics in Beijing. Methods: Epidemiological investigation and big data were used to identify the exposure points of the cases. Close contacts were traced from the exposure points, and the cases' and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: The Omicron variant causing 3 outbreaks in Beijing from January to April, 2022 belonged to BA.1, BA.1.1 and BA.2. The outbreaks lasted for 8, 12 and 8 days respectively, and 6, 42 and 32 cases infected with 2019-nCoV were reported respectively. International mail might be the infection source for 1 outbreak, and imported clothes might be the infection sources for another 2 outbreaks. The interval between the shipment start time of the imported goods and the infection time of the index case was 3-4 days. The mean incubation period (Q1, Q3) was 3 (2,4) days and the mean serial interval (Q1, Q3) was 3 (2,4)days. Conclusions: The 3 outbreaks highlighted the risk of infection by Omicron variant from international logistics-related imported goods at normal temperature. Omicron variant has stronger transmissibility, indicating that rapid epidemiological investigation and strict management are needed.

Survey of possible aerosol transmission of a COVID-19 epidemic caused by 2019-nCoV Delta variant / 中华流行病学杂志

Objective: To investigate the epidemiological characteristics and the transmission chain of a family clustering of COVID-19 cases caused by severe acute respiratory 2019-nCoV Delta variant in Changping district of Beijing. Methods: Epidemiological investigation was conducted and big data were used to reveal the exposure history of the cases. Close contacts were screened according to the investigation results, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: On November 1, 2021, a total of 5 COVID-19 cases caused by 2019-nCoV Delta variant were reported in a family detected through active screening. The infection source was a person in the same designated isolation hotel where the first case of the family cluster was isolated from 22 to 27, October. The first case was possibly infected through aerosol particles in the ventilation duct system of the isolation hotel. After the isolation discharge on October 27, and the first case caused secondary infections of four family members while living together from October 27 to November 1, 2021. Conclusion: 2019-nCoV Delta variant is prone to cause family cluster, and close attention needs to be paid to virus transmission through ventilation duct system in isolation hotels.

Early detection on the onset of scarlet fever epidemics in Beijing, using the Cumulative Sum / 中华流行病学杂志

[Introduction] Based on data related to scarlet fever which was collected from the Disease Surveillance Information Reporting System in Beijing from 2005 to 2011,to explore the efficiency of Cumulative Sum (CUSUM) in detecting the onset of scarlet fever epidcmics.Models as C1-MILD (C1),C2-MEDIUM (C2) and C3-ULTRA (C3) were used.Tools for evaluation as Youden' s index and detection time were calculated to optimize the parameters and optimal model.Data on 2011 scarlet fever surveillance was used to verify the efficacy of these models.C1 (k=0.5,H=2σ),C2 (k=0.7,H=2σ),C3 (k=1.1,H=2σ) appeared to be the optimal parameters among these models.Youden' s index of C1 was 83.0％ and detection time being 0.64 weeks,Youden' s index of C2 was 85.4％ and detection time being 1.27 weeks,Youden' s index of C1 was 85.1％ and detection time being 1.36 weeks.Among the three early warning detection models,C1 had the highest efficacy.Three models all triggered the signals within 4 weeks after the onset of scarlet fever epidemics.The early warning detection model of CUSUM could be used to detect the onset of scarlet fever epidemics,with good efficacy.

The genetic features of drug resistance to group A streptococcus and macrolides antibiotics among pediatric patients in Beijing 2012 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the genetic features of drug resistance to group A streptococcus(GAS) and macrolides antibiotics among pediatric patients in Beijing 2012.</p><p><b>METHODS</b>A total of 199 strains of GAS were collected from 36 hospitals in Beijing between May and July, 2012. All strains were isolated from oropharyngeal swabs. The minimum inhibitory concentrations (MICs) of ten antibiotics (penicillin, ampicillin, erythromycin, clindamycin, tetracycline, levofloxacin, tigecycline, vancomycin, linezolid and streptogramin) were detected by VITEK-2 compact with GPS-67 test kit. The genes encoding macrolides resistance (ermA, ermB and mefA ) were amplified and tested by PCR. The macrolides resistant phenotype of group A streptococcus was detected by double disc test (D-test).</p><p><b>RESULTS</b>Among 199 strains of GAS collected in this study, 101(50.8%) were from suburbs and the other 98(49.2%) were from urban areas. 111(55.8%) strains were collected from scarlet fever patients while the other 88(44.2%) were from oropharyngeal infection cases. All the strains were sensitive to penicillin and ampicillin, and the percentage of resistance to erythromycin, clindamycin and tetracycline were 96.5% (192/199), 95.5% (190/199) and 92.0% (183/199), respectively. All strains were susceptible to levofloxacin, tigecycline, vancomycin, linezolid and streptogramin. The rates of resistance to erythromycin, clindamycin and tetracycline were different in different districts, however, the difference in it between ages and clinical diagnosis did not show statistical significance (P > 0.05) . The detected rate of drug resistance gene ermB was 98.5% (196/199). The gene ermA was only detected out in 5 strains and the gene mefA was not detected out. 199 strains showed A macrolides resistant phenotype cMLS, while the phenotype iMLS was not found in this study.</p><p><b>CONCLUSION</b>This study demonstrates the high level of clindamycin resistance in group A streptococcus collected from children in Beijing, 2012. The macrolides resistance of group A streptococcus was highly prevalent in Beijing, and the dominant phenotype was cMLS mediated by gene ermB.</p>

Characteristics and related factors related to the resistance on antibiotics among group A streptococcus strains isolated from children in Beijing, during May and July 2011 / 中华流行病学杂志

Objective To analyze the characteristics of antibiotic resistance on group A streptococcus isolated from pediatrics in Beijing in 2011,to provide reference for clinical drug administration.Methods Strains of group A streptococcus were collected from the Departments of Pediatrics in 36 hospitals at different Districts of Beijing,from May to July 2011.Minimal inhibitory concentrations (MIC) with ten antibiotics of these isolates were tested by VITEK 2 Compact method.All the Susceptibility rate (S％),Intermediate rate (I％) and Resistance rate (R％) were calculated according to their MIC values.The macrolides resistant phenotype of group A streptococcus was detected by D-test.Results A total of 633 (19.1％) group A streptococcus strains were cultured from 3315 throat swabs.All the isolates were susceptible to penicillin,ampicillin,streptogramin,linezolid,tigecycline,vancomycin,while 96.5％ (611/633) of the isolates were susceptible to levofloxacin.A total of the 96.1％ (608/633) isolates exhibited resistance to erythromycin.The resistance rates to clindamycin and tetracycline were 79.3％ (502/633)and 93.7％ (593/633),respectively.A total of 9 different resistant patterns were observed,with the dominant patterns as:concomitant resistance to erythromycin,clindamycin and tetracycline (72.7％,460/633),followed by combined resistance to erythromycin and tetracycline (18.0％,114/633).The most commonly seen macrolide resistant phenotype was cMLS type (83.2％).In total,97 strains belonged to iMLS type and 5 strains to M type.Data through multivariate logistic regression analysis showed that factors as occupation and samples being collected from the sub-unban areas etc.were significantly associated with the resistance rates to tetracycline and the odds ratio (95％CI) as 2.43 (1.16-5.09) and 2.35 (1.47-3.73).Isolates collected from the sub-unban areas were significantly associated with resistance rates to clindamycin,with the odds ratio (95％CI) being 0.48(0.25-0.92).Conclusion All the isolates acquired from the Pediatrics Departments in Beijing were susceptible to penicillin and ampicillin.The high resistance rates of erythromycin,clindamycin and tetracycline resistance to group A streptococcus were observed,with the major resistant phenotype as cMLS.Factors as occupation and the collection site of samples were significantly associated with the resistance rates to tetracycline while the sites of sample collection were significantly associated with the resistance rates to clindamycin.

Study on the risk factors of diarrhea-related behaviors among adults in Beijing / 中华流行病学杂志

Objective To study the risk behaviors on diarrhea among the adults of Beijing.Methods 13287 adults aged over 18 years in Dongcheng,Xicheng,Haidian,Changping,Huairou and Tongzhou districts in Beijing were selected with a multi-stage stratified sampling method.Information on the demographic characteristics,with or without symptoms on diarrhea in the last year,and behaviors related to diarrhea,were collected through a self-designed questionnaire.Results The reported total prevalence of diarrhea symptoms in the last year was 17.6％ and,in urban areas as 16.8％,in rural areas as 18.2％ respectively.The differences on the reported prevalence rates of diarrhea in different age groups,background of education and occupations groups among urban residents were statistically significant (P＜0.05).Items as eating raw seafood or freshwater products,using the same chopping block and knife at the time when processing raw and cooked food,not being used to regular physical exercise etc.were the risk factors to diarrhea among adults from urban areas,with OR (95％CI) as 1.26 ( 1.07-1.48),1.37 (1.16-1.63) and 1.38 ( 1.20-1.59),respectively.The reported diarrhea prevalence rates related to sex,age,education background and occupations among rural residents did not show significant differences (P＞0.05).Without hand-washing habit before eating or after toilet-using,eating raw seafood or freshwater products,using the same chopping block and knife at the time when processing raw and cooked food,not being used to regular physical exercise etc.seemed to be the risk factors on diarrhea among adults in the rural areas with the OR(95％CI) as 1.85 (1.51-2.25),1.39 (1.17-1.67),1.44 (1.24-1.67) and 1.46 (1.27-1.67),respectively.Conclusion The prevalence reported on diarrhea symptoms among adults from the rural areas was higher than the urban adults.Diarrhea was related to health-related habits,eating habits and regularity of taking physical exercises.

Study on the index system in evaluating the adult health literacy situation related to infectiousdisease in Beijing / 中华流行病学杂志

Objective To establish and assess a comprehensive index system on adult health literacy which related to infectious disease.Methods A multi-stage stratified sampling method was carried out among adults aged over 18 years,in Bcijing.A questionnaire survey was used to collect the information on adult health literacy situation related to infectious disease,with answers scored.Degrees of difficulty and difference together with confirmatory factor analysis were used to screen the indications from the questionnaires so as to establish a comprehensive index system.Methods as Cronbach a coefficient,split-half reliability,confirmatory factor analysis and cluster analysis methods were used to assess the reliability and validity of the index system.Results The sample size was 13 287 with valid questionnaires as 13 001.There were 30 indexes selected to establish the comprehensive index system on adult health literacy related to infectious disease.The Cronbach a coefficient was 0.777,and the split-half reliability was 0.609.Data from Confirmatory factor analysis revealed that each of the standardized regression coefficient was significant,and there were significant differences between the groups of being clustered by Q cluster analysis method (P＜0.001).9.9％ of the residents were classified as having enough knowledge on health.Conclusion The index system set for adult health literacy that related to infectious disease showed good reliability and validity thus could be used as a good tool to evaluate the levels of health literacy which related to infectious diseases,in Beijing.

Study on types of M protein gene in group A streptococcus isolated from children in Beijing, 2011 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the distribution characteristics of the types of M protein gene (emm) in group A streptococcus (GAS) isolated from children in Beijing in the year 2011.</p><p><b>METHODS</b>During May to July in 2011, a total of 3315 patients who were diagnosed scarlet fever or pharyngeal infection by doctors in pediatric outpatient and emergency units of 36 hospitals, were selected as subjects. Their throat swab samples were collected and isolated the strains of GAS. Gene emm was then amplified and sequenced by PCR method, and the differences in types of gene emm between different populations and diseases were compared.</p><p><b>RESULTS</b>A total of 633 strains of GAS were isolated from the 3315 throat swab samples, 610 strains out of which were gene emm positive and were recruited in the study. Out of the 610 recruited strains, 448 (73.4%) were isolated from scarlet fever patients, the other 162 (26.6%) were isolated from pharyngeal infection patients; 397 (65.1%) were from urban, the other 213 (34.9%) were from suburb; 240 (39.4%) were from patients aging between 1 - 5 years old, the other 369(60.6%) were from patients aging 6 - 18 years old. A total of 8 types of gene emm (scarlet fever: 6 types, pharyngeal infection: 4 types) and 21 subtypes of gene emn (scarlet fever: 16 subtypes, pharyngeal infection: 10 subtypes) were identified. Three new subtypes were found in the study, naming emm1.63, emm12.62 and st5144.20. Among them, emm1.63 was found both in scarlet fever and pharyngeal infection patients, while emm12.62 and st5144. 20 were only found in pharyngeal infection patients. Among all the types of gene-emm, emm12 accounted for the highest percentage as 80.5% (491/610) and then followed by emm1 (18.0% (110/610)). Among all the subtypes, the dominant subtype was emm12.00, accounting for 69.0% (421/610), following by emm1.00 (16.9% (103/610)) and emm12.19 (6.1% (37/610)). All the above types and subtypes of gene emm were the most prevalent strains in scarlet fever patients and pharyngeal infection patients. Significant differences in the distribution of prevalent strains were observed among various aging patients and regions. The constituent ratios of emm1, emm1.00 and emm12.19 were higher in patients from suburb (emm1: 22.1% (47/213), emm1.00: 19.2% (40/213), emm12.19: 8.0% (17/213)) than those in urban areas (emm1: 15.9% (63/397), emm1.00: 15.6% (62/397), emm12.19: 5.0% (20/397)). The difference showed statistical significance (P < 0.05). The constituent ratio of emm1.00 was higher among patients aging 6-18 years old (19.2% (71/369)) than those aging 1 - 5 years old (13.3% (32/240)). The difference also showed statistical significance (χ(2) = 8.45, P < 0.05).</p><p><b>CONCLUSION</b>Among the types of gene emm in GAS isolated from children in Beijing in year 2011, the most prevalent two were emm12 and emm1, and the most prevalent emm subtypes were emm12.00, emm1.00 and emm12.19. A significant difference in their distribution between various aging patients and isolated places can be obviously found.</p>

The coverage rate and obstructive factors of influenza vaccine inoculation among residents aged above 18 years in Beijing from 2007 to 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To assess the coverage rate and obstructive factors of influenza vaccine inoculation among residents aged above 18 years in Beijing from 2007 to 2010.</p><p><b>METHODS</b>A total of 13 287 residents were recruited from six districts in Beijing. Information included demographic data, whether or not got vaccinated from 2007 to 2010, and the reasons for non-vaccination were collected using the questionnaires.</p><p><b>RESULTS</b>A total of 13 002 copies of questionnaires were valid and retrieved. The coverage rates of influenza vaccine inoculation among Beijing residents aged above 18 years between year 2007 and 2010 were 14.2% (1850/13 001), 18.0% (2345/13 002), 23.4% (3036/13 002) and 18.6% (2416/13 002), respectively. The 4-year adherent inoculation rate was 9.1% (1186/13 001). The coverage rates in the subjects aged over 60 years, less educated, medical-practitioner or retired were relative higher, with the 4-year adherent inoculation rate at 24.4% (614/2521), 24.4% (94/386), 14.6% (47/323) and 19.0% (386/2036). The factors induced non-vaccination among residents included "I don't think I am very likely to catch the flu" (51.2%, 6002/11 722), "I have no spare time to get vaccinated" (18.3%, 2145/11 722), "The influenza vaccination is too expensive" (15.8%, 1852/11 722), "I am afraid of the side-effects" (15.2%, 1782/11 722), "I don't believe the vaccine is effective enough" (12.9%, 1512/11 722), "I don't think influenza is a serious disease" (10.1%, 1184/11 722), "I have the specific contraindications" (7.3%, 856/11 722), and "I have never heard influenza vaccination before" (5.2%, 610/11 722). With regard to the reasons for non-vaccination, significant differences were found among subjects with different educated levels, different ages and different occupations. The proportion of thoughts "I don't think I am very likely to catch the flu" among the residents in five educational levels (illiterates or semi-illiterates, primary school, junior middle school, senior middle school and college or above) were 28.6% (83/289), 39.8% (473/1188), 49.1% (1642/3341), 50.7% (1719/3392) and 51.3% (1794/3501) respectively, with a significant statistical difference (χ(2) = 98.33, P < 0.01).</p><p><b>CONCLUSION</b>The coverage rates of influenza vaccine inoculation were low among residents aged above 18 years from 2007 to 2010 in Beijing. The main reasons for non-vaccination included lack of information about risk in influenza infection and its severity to health, and anxiety about vaccine safety and effectiveness.</p>

Association between socioeconomic status and physical activities in Chinese children / 中华流行病学杂志

Objective To study the daily physical activity patterns of pupils in Beijing, and to identify the association between the socioeconomic status (SES) and physical activities. Methods 1502 pupils were recruited from 2-5 grades of eight primary schools in Beijing. Information on physical activity, sedentary activity, and transportation styles inside and outside schools were collected using a "7-day physical activity questionnaire". Results Gymnastics, running, playing games, walking in queues etc. Were the most common activities at school, with the proportion as 94.13%, 85.55%, 77.26%, and 71.32% respectively. Physical labor, playing games, running and walking were the common activities outside schools, with the proportion as 72.14%, 69.70%,65.05%, and 64.64% respectively. However, pupils seldom participated in the ball games. Significant differences between SES groups were observed on the patterns of both physical and sedentary activities. Compared to low-SES pupils, high-SES pupils more frequently participated in dancing, walking upstairs or downstairs, swimming, skating, but less frequently (P＜0.05) in walking, rope skipping, kicking shuttlecock or rubber band skipping. Conclusion Data from our study showed that both the quantity and the distribution of different activities did not meet the need of the Chinese children. Physical activity in association with SES was also demonstrated.

Study on the trend of minority students' health status from 1995 to 2005 in China / 中华流行病学杂志

myopia rates in 2005 were 29.5%, 39.1%, 10.1%, 42.6%, 41.1%, for boys and 45.4%, 50.0%, 15.4%, 49.7%, 46.7% for girls. Conclusion In order to improve the health of students in minority regions, we need to promote health education at schools.

Secular changes on the morphological development and nutrition status of Tibetan students from 1985 to 2005 / 中华流行病学杂志

Objective To study the secular changes on both morphological development and nutritional status among Tibetan students, from 1985 to 2005. Methods Data from the Chinese national survey on students' physical fitness and health in 1985, 1995, 2000 and 2005 were used to analyze and find out the difference of the morphological development and nutrition status of Tibetan students aged 7-18 years in different years. Results From 1985 to 2005, the height and weight of Tibetan students had a growing trend. The height and weight of schoolboys and schoolgirls aged 7-18 years increased 3.94 cm, 5.08 kg, 2.25 cm, and 4.24 kg respectively, while the circumference decreased without significance. The prevalence rates of underweight and malnutrition in Tibetan students further went down along with the improvement of their nutritional status. However, the prevalence rates on both overweight and obesity increased continuously, affecting the health status of Tibetan students. Conclusion From 1985 to 2005, the morphological development of Tibetan students had a growing trend and their nutrition status improved. However, the prevalence of overweight and obesity continuously increased.

Changes of physical functions among Chinese minority students from 1985 to 2005 / 中华流行病学杂志

Objective To study the changes of physical functions among minority students in China from 1985 to 2005, to provide evidence for health promotion to the minority students in the country. Methods Using data from the Chinese national survey on students physical fitness and health from 1985 to 2005, we analyzed the physical functions of 15 minority groups from primary and secondary schools, including Mongolian, Hui, Uygur, Zhuang, Korean, Tibetan, Yao, Li, Qiang, Buyi, Dong, Miao, Tu, Salar, Kirgiz, aged 7-18 years old. Results Some of the minority students had the higher levels of physiological functions and athletic ability, but some indicators decreased significantly. In terms of items related to 'speed' , most of the minority boys and girls improved, but items related to 'endurance' or 'vital capacity', were significantly declining. Part of the minority students bad better 'endurance' than students of Hart ethnicity in the cities. All the indicators of athletic ability declined in schoolboys and schoolgirls of Korean ethnicity. Kirgiz students were outstanding in vital capacity and speed quality while Uighur students had better physical development and vital capacity, but were poorer in running and jumping, reflecting the weakness of explosive power of lower limbs. On the contrary, Li and Zhuang students had shown a very good quality in running, jumping, male shoulder muscular strength and endurance items, etc. Conclusion The physical functions and the athletic ability of the minority students in China had the advantages and characteristics, which might be related to their living environment and habits.

Prevalence rates of overweight and obesity in Chinese minority students in 2005 / 中华流行病学杂志

ghest. Conclusion In general, both the prevalence rates of overweight and obesity in Chinese minority students were comparatively low. However, in some minority groups the prevalence had already become higher, which demands early prevention.