Impact of COVID-19 control measures on the spread of influenza / 上海预防医学

ObjectiveTo analyze the effects of respiratory control measures before and after COVID-19 epidemic on influenza virus. MethodsThe percentage of influenza-like cases， the positive rate of influenza virus and the change of influenza outbreaks before and after the COVID-19 pandemic were compared and analyzed by selecting the data of influenza surveillance sentinel-points in Shanghai. ResultsThe percentage of influenza-like illness after the outbreak of COVID-19 in 2020 was significantly higher than that during the same period between 2017 and 2019. The positive rate of influenza virus detection in 2020 was significantly lower than the average rate of influenza virus detection from 2017 to 2019 with significant statistical difference （χ 2=2 359.07， P<0.001）. The number of outbreaks in 2020 was significantly lower than that from 2017 to 2019. ConclusionDuring the respiratory season， personal protection and reduction of human aggregation can effectively reduce the infection of influenza and the incidence of influenza in the population.

Impact of COVID-19 control measures on the spread of influenza / 上海预防医学

ObjectiveTo analyze the effects of respiratory control measures before and after COVID-19 epidemic on influenza virus. MethodsThe percentage of influenza-like cases， the positive rate of influenza virus and the change of influenza outbreaks before and after the COVID-19 pandemic were compared and analyzed by selecting the data of influenza surveillance sentinel-points in Shanghai. ResultsThe percentage of influenza-like illness after the outbreak of COVID-19 in 2020 was significantly higher than that during the same period between 2017 and 2019. The positive rate of influenza virus detection in 2020 was significantly lower than the average rate of influenza virus detection from 2017 to 2019 with significant statistical difference （χ 2=2 359.07， P<0.001）. The number of outbreaks in 2020 was significantly lower than that from 2017 to 2019. ConclusionDuring the respiratory season， personal protection and reduction of human aggregation can effectively reduce the infection of influenza and the incidence of influenza in the population.

Epidemiologic characteristics of influenza in Shanghai from 2013 to 2015 / 上海预防医学

Objective To study the epidemiologic characters of influenza in Shanghai from 2013 to 2015 . Methods Data of outpatient visits for influenza-like illness ( ILI ) were collected through influenza surveillance hospitals .Pathogenic surveillance to part of ILI samples was conducted . Results From 2013 to 2015, the ILI consultation rate ranged from 0.68%~3.73%, with an average rate of 1 .46%.In total 51 445 samples were collected , and 12673 samples were positive , with the positive rate of 24 .63%.The ratio of the patient visited for ILI aged from 25 to 60 was higher than other groups . Conclusion The peak of epidemic of influenza in Shanghai was in winter and summer .The ratio of the patients visited for ILI aged over 60 increased with years .More measures should be taken to protect the elder people .

Preliminary application of Back-Propagation artificial neural network model on the prediction of infectious diarrhea incidence in Shanghai / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish BP artificial neural network predicting model regarding the daily cases of infectious diarrhea in Shanghai.</p><p><b>METHODS</b>Data regarding both the incidence of infectious diarrhea from 2005 to 2008 in Shanghai and meteorological factors including temperature, relative humidity, rainfall, atmospheric pressure, duration of sunshine and wind speed within the same periods were collected and analyzed with the MatLab R2012b software. Meteorological factors that were correlated with infectious diarrhea were screened by Spearman correlation analysis. Principal component analysis (PCA) was used to remove the multi-colinearities between meteorological factors. Back-Propagation (BP) neural network was employed to establish related prediction models regarding the daily infectious diarrhea incidence, using artificial neural networks toolbox. The established models were evaluated through the fitting, predicting and forecasting processes.</p><p><b>RESULTS</b>Data from Spearman correlation analysis indicated that the incidence of infectious diarrhea had a highly positive correlation with factors as daily maximum temperature, minimum temperature, average temperature, minimum relative humidity and average relative humidity in the previous two days (P < 0.01), and a relatively high negative correlation with the daily average air pressure in the previous two days (P < 0.01). Factors as mean absolute error, root mean square error, correlation coefficient(r), and the coefficient of determination (r(2)) of BP neural network model were established under the input of 4 meteorological principal components, extracted by PCA and used for training and prediction. Then appeared to be 4.7811, 6.8921,0.7918,0.8418 and 5.8163, 7.8062,0.7202,0.8180, respectively. The rate on mean error regarding the predictive value to actual incidence in 2008 was 5.30% and the forecasting precision reached 95.63% .</p><p><b>CONCLUSION</b>Temperature and air pressure showed important impact on the incidence of infectious diarrhea. The BP neural network model had the advantages of low simulation forecasting errors and high forecasting hit rate that could ideally predict and forecast the effects on the incidence of infectious diarrhea.</p>

A case-control study on risk factors that associated with severe hand-foot-mouth disease in Shanghai / 中华流行病学杂志

Objective To explore the factors associated with severe hand-food-mouth disease (HFMD) case in Shanghai.Methods A total of 105 severe HFMD cases diagnosed from May to July,2011 in Shanghai were enrolled as case group while another 210 mild HFMD cases were randomly selected as control group in the same period.All subject' s parents or babysitters were asked to fill in the questionnaire in which including demography,ways of babysitting,behavior and the like.All HFMD cases were diagnosed by both clinical symptom and nuclear acid testing.Data was processed by EpiData (V3.0) and analyzed by SPSS (V17.0).Results Factors as age,gender,Diaspora pattern,migrant,size of house,numbers of family member,numbers of children,frequency of seeing doctor,dishware that sharing with babysitter,food chewed by babysitter,dirty hand,EV71 virus type and diagnosis on HFMD in the fist visit to hospital were found associated with severe HFMD by univariate analysis.Results through multivariate logistic regression showed that factors including:being the only male kid,more than 3 children in the family,dirty hands,unable to be diagnosed as HFMD in the first visit to the hospital,visiting doctor during the past 6 months for 2 and 3 times etc.could be kept in the model with statistical threshold of 0.05.Adjusted ORs and confidence intervals of them were 2.431 ( 1.317-4.487),2.661 (1.332-5.315),3.403 ( 1.871-6.191 ),6.607 (3.011-14.500),2.431 ( 1.111-5.321 ),2.628 ( 1.137-6.071 ) respectively.Being Infected by EV71 was also found a very important risk factor compared with CoxA16 or other enteroviruses,and its adjusted OR was 5.614 (2.409-13.082).Conclusion It was necessary to implement molecular diagnosis for identifying the virus type of HFMD,together with improvement on the capacity of clinical diagnosis in order to diagnose the HFMD cases earlier.More attention should be paid to these HFMD cases with EV71 infection as well as prompting frequent visits to hospitals on those families with more children.