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.

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.

Exposure to avian influenza virus and the infection status of virus among people breeding or butchering ducks in the suburb of Beijing / 中华流行病学杂志

Objective To understand the exposure and the infection status of virus among people engaging in breeding or butchering ducks in the suburb of Beijing.Methods People from six districts (Daxing,Fangshan,Huairou,Miyun,Shunyi,Tongzhou) who engaged in breeding or butchering ducks were studied and the status of infecting avian influenza virus was obtained by testing antibody level in serum.Information on demographic characteristics,status of regular exposure and exposure to sick or dead poultry were collected through a self-designed questionnaire.Results 1741people were involved in this study in which 313 (18.0％ ) were workers in duck-breeding enterprise,562 (32.3％) were workers in duck slaughterhouse,261 (15.0％) farmers were in individualsmall-scale duck farms,605 (34.7％) were farmers raising duck in backyard.Among farmers raising duck in backyard,the percentage of people whose ducks ever contacted with wild birds was higher than the other three groups (66.8％)(P＜0.05).Among farmers who bred their ducks in the backyard (35.2％) and those abattoir workers (31.3％ ),the percentage of people who had contacted ducks but not been vaccinated with avian influenza vaccine was higher than the other two groups (P＜0.05).Regarding the status on cleaning and disinfection among the studied farmers who had bred their ducks in the backyard,the percentage of people who had closer contact with ducks would clean the settings more than 4 times per month (8.8％) and disinfected those places more than 12 times per year (27.3％) but still lower than the other three groups (P＜0.05).Among those farmers who bred ducks in the backyard,the percentage of people who had ever touched duck with their hands was high (34.4％) (P＜ 0.05).Regarding exposure to sick or dead poultry,higher proportion was found among those who had ever closely contacted sick or dead poultry commercial duck raisers (36.1％) and individuals who raise large amount of ducks (36.0％).70.8％ of the individual duck raisers had never taken any protective measures when closely contacting the sick or dead poultry.Among 1741 samples,0 were positive to avian influenza virus H5 and H7 subtypes.12 were positive to H9 subtype (positive rate was 0.7％ ),in which 10 were farmers raising ducks in backyard (the positive rate of 1.7％ ).Differences between H9 subtype antibody positive rates difference in 4 population groups were statistically significant (x2=13.699,P＜0.05).Conclusion Farmers who bred their ducks in the backyard had greater risk of contracting the avian influenza.Individual duckers who raise ducks in large scale and the farmers who bred their ducks in the backyard were in lack of protective measures when contacting the sick or dead poultry.Our findings suggested that some intervention measures should be taken to reduce the risk of avian influenza infection.

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>