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Abstract@#On October 13 2023, the Beijing Economic and Technological Development Area Center for Disease Control and Prevention recAAAAAeived a report from a school indicating an outbreak of fever among students in Class 2, Grade 4. An on-site epidemiological investigation was immediately conducted. A total of 14 cases were reported, all of whom were students, with an attack rate of 34.15%. The onset of illness was concentrated between October 6 and 15, with the main clinical symptoms being fever, cough and fatigue. There were no cases of hospitalization, severe illness or death. Seven cases tested positive for Mycoplasma pneumoniae P1-Ⅱ. Based on the on-site investigation and laboratory test results, it was an outbreak of influenza-like illness caused by Mycoplasma pneumoniae infection. The likely cause of the spread was cases infecting other classmates through respiratory droplets while attending class. The outbreak occurred only in one class and did not spread to neighboring classes. Schools should actively carry out health education to raise awareness among parents for reporting infectious diseases, and strengthen morning and afternoon screenings to improve the sensitivity of identification.
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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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@#Objective To understand the epidemiological and etiological characteristics of influenza in Mianyang City from 2019 to 2021, so as to provide a basis for the prevention and control of influenza. Methods Influenza surveillance data in Mianyang City from 2019 to 2021 were collected and analyzed statistically. Results A total of 55 970 cases of influenza were reported in Mianyang City from 2019 to 2021, with an average annual incidence of 388.08/100 000. A total of 103 723 cases of influenza -like illness cases (ILI) were reported, with an average annual ILI% of 3.58%. The incidence, ILI% , and positive detection rates of influenza were all far higher than those in the corresponding period in 2019. The classification of the population is mainly composed of students under the age of 15. The top three reported cases were Fucheng District (20 118, 35.94%), Youxian District (6 394, 11.42%) and Jiangyou District (5 800, 10.36%). 10 126 samples of ILI were received and detected, with a positive rate of 19.53%, the positive rate of ILI samples was mainly students under 15 years old. The dominant strains of influenza viruses showed an alternating trend over the years, and A (H3) was the predominant type in 2019. Except for 2 A (H9) strains detected in 2021, the rest were all BV strains. Due to the impact of COVID-19 in 2020, the positive detection rate was low throughout the year. 43 outbreaks of ILI were reported, which were mainly occurred in winter, and most of them were in primary schools. Conclusion From 2019 to 2021, the characteristics of cases, ILI, pathogen surveillance and outbreak events of influenza in Mianyang City are basically the same, with students under 15 years of age and schools remaining the key population and sites of concern. the importance of non-pharmaceutical interventions for influenza prevention and control is further evidenced by the low incidence of influenza during the COVID-19 pandemic.
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@#Abstract: Objective To evaluate the influence of coronavirus disease 2019 (COVID-19) prevention and control measures on the transmission and epidemic of influenza in Chongqing, so as to provide references for formulating targeted influenza prevention and control strategies. Methods The influenza surveillance data, during the year 2018 to 2020, were collected through the "China Influenza Surveillance Information System", and the seasonal characteristics of influenza epidemic were analyzed. The percentage of influenza like cases (ILI%) and influenza virus positive rate between 2020 and 2018-2019 were compared, so as to evaluate the impact of COVID-19 prevention and control measures on influenza epidemic characteristics. Results The annual proportions of ILI cases in Chongqing were respectively 3.53%, 2.23% and 1.2% from 2018 to 2020, while the positive rates of influenza virus were respectively 13.97%, 23.81% and 2.65%. The distribution trend of ILI% from 2018 to 2019 fluctuated were similar, but it continued to drop and remain at a low level since February 2020. The positive rate of influenza virus showed an epidemic peak from December to March in 2018-2019, also peaked from November 2019 to January 2020, but decreased to 0 in March. ILI% was positively correlated with the positive rate of influenza virus (r=0.404 8, P<0.05). In 2020, compared with the same period of 2018-2019, the growth rate of ILI% was -66.09% and -46.32%, respectively. The positive rate of influenza virus in 2020 decreased by 81.03% and 88.87% compared with the same period of 2018-2019, respectively. The growth rates of influenza virus positive rate in January 2020 were decreased with a small rate of about 39.87%, and with a significantly decline of more than 93.65% from February. No influenza epidemic was found after March. Conclusions Since COVID-19 prevention and control measures were implemented in January 2020 in Chongqing, the ILI% and the positive rate of influenza virus in sentinel hospitals decreased significantly. In the season of high incidence of respiratory infectious diseases, personal protection and other measures can effectively reduce influenza virus infection.
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The purpose of this study was to investigate the epidemiological characteristics and risk factors of influenza in Hainan province,to provide evidence to support influenza prevention and control efforts.Pathogen monitoring data of influenza-like illness(ILI)in six national sentinel hospitals in Hainan province from 2013 to 2021 were analyzed in SPSS 20.0 software.A total of 50 415 ILI cases were detected during the 2013-2021 season,of which 5 581 were positive for influenza viruses,with a positivity rate of 11.07％.The dominant strains were type B,type A(H1N1)pdm09 and type A(H3N2).The positivi-ty rate of influenza virus was highest in people 5-14 years of age(17.56％)and lowest in people 0-4 years of age(7.32％).Influenza activity showed both a summer peak and a winter-spring peak in the 2014-2016,2017-2018 and 2019-2020 sea-sons,and was concentrated in April to September,with a maximum peak of 53.64％,and in November to March of the next year,with a peak of 47.30％.The 2013-2014,2016-2017 and 2018-2019 seasons showed only a winter-spring peak concen-trated between October and March of the next year,with a maximum peak of 54.17％,but no obvious summer peak.The pre-dominant influenza viruses during the eight surveillance seasons varied among H1N1,H3N2 and type B.The positive detection rate of influenza virus steeply declined during the 2020-2021 season:the positive detection rate was only 0.25％,and no obvi-ous epidemic period was observed.The intensity of influenza epidemic varied among monitoring years,and the dominant strains changed rapidly in Hainan Province.People 5-14 years of age were the key population affected.Summer,winter and spring were the key periods for influenza prevention and control.Etiological surveillance of influenza should continue to be strength-ened,the roles of health education and publicity should be emphasized,and the dual measures of influenza vaccination and non-drug intervention should be actively promoted to decrease the occurrence of influenza.
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Objective @# To analyze the epidemiological characteristics of influenza in Anhui province from 2018 to 2023 , and to explore the change rule of influenza etiology , so as to provide reference for the prevention and control of influenza. @*Methods @#Sentinel hospital surveillance data and network laboratory etiological surveillance data of influenza⁃like cases (ILI) in Anhui province from 2018 to 2023 were collected by " China influenza surveillance information system" , and the data were analyzed using Excel 2019 and SPSS 25. 0.@*Results @#From 2018 to 2023 , ILI% in Anhui province were 3. 74% , 4. 26% , 3. 53% , 4. 34% , 6. 80% , respectively. The positive rates of influenza virus were 14. 87% , 19. 98% , 0. 12% , 12. 39% and 24. 72% , respectively. There were significant differences in time distribution and age distribution of ILI% and influenza virus positive rates (P < 0. 001) . Influenza mainly occurred from December to March and from June to August in Anhui province. The positive rate of influenza virus detection was the highest among children under 15 years old , which was the main population of influenza cases. The outbreaks had mainly occurred in primary and secondary schools and childcare facilities.@*Conclusion@#There are two incidence peaks of influenza each year, one is in winter and spring , another one is in summer. From December to March , from June to August are the critical periods of influenza control and prevention. Children under 15 years old are the key groups and schools are the key places of influenza control and prevention. Continuous influenza surveillance can provide scientific basis for the prevention and control of influenza in Anhui province.
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ObjectiveTo predict the incidence trend of influenza-like illness proportion （ILI%） in Shanghai using the seasonal autoregressive integrated moving average model （SARIMA）， and to provide an important reference for timely prevention and control measures. MethodsTime series analysis was performed on ILI% surveillance data of Shanghai Municipal Center for Disease Control and Prevention from the 15th week of 2015 to the 52nd week of 2019， and a prediction model was established. Seasonal autoregressive integrated moving average （SARIMA） model was established using data from the foregoing 212 weeks， and prediction effect of the model was evaluated using data from the latter 36 weeks. ResultsFrom the 15th week of 2015 to the 52nd week of 2019， the average ILI% in Shanghai was 1.494%， showing an obvious epidemic peak. SARIMA（1，0，0） （2，0，0） 52 was finally modeled. The residual of the model was white noise sequence， and the true values were all within the 95% confidence interval of the predicted values. ConclusionSARIMA（1，0，0） （2，0，0） 52 can be used for the medium term prediction of ILI% in Shanghai， and can play an early warning role for the epidemic and outbreak of influenza in Shanghai.
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Background: Influenza activity was reported to be below the seasonal levels during the Coronavirus disease?2019 (COVID?19) pandemic globally. However, during the severe acute respiratory syndrome corona virus?2 outbreak, the routine real?time surveillance of influenza?like illness and acute respiratory infection was adversely affected due to the changes in priorities, economic constraints, repurposing of hospitals for COVID care, and closure of outpatient services. Methods: A systematic review and meta-analysis were carried out to assess the pooled proportion of symptomatic cases tested for influenza virus before the current pandemic in 2019 and during the pandemic in 2020/21. An electronic search of PubMed/MEDLINE, Scopus, and Google Scholar was carried out for the articles reporting the impact of the COVID?19 pandemic on influenza surveillance among humans using search terms. The study was designed based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines and the meta-analysis was performed to synthesize the pooled proportion of patients sampled for influenza with 95% confidence interval (CI). Results: The nine qualified studies from the WHO European region, Canada, Japan, Germany, Italy, Spain, South Africa, and the United States were pooled by random?effects meta?analysis. The overall pooled proportion of symptomatic cases sampled for influenza surveillance before and during the pandemic was 2.38% (95% CI 2.08%–2.67%) and 4.18% (95% CI 3.8%–4.52%), respectively. However, the pooled proportion of samples tested for influenza before the pandemic was 0.69% (95% CI 0.45%–0.92%) and during the pandemic was 0.48% (95% CI 0.28%–0.68%) when studies from Canada were excluded. Conclusion: The meta-analysis concludes that globally there was a decline in influenza surveillance during the COVID?19 pandemic except in Canada.
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ObjectiveTo analyze the influenza surveillance data in Ezhou City， Hubei Province from 2016 to 2021， determine the epidemiological characteristics and etiological trend of influenza like illness （ILI）， and to provide scientific evidence for influenza prevention and control. MethodsThe ILI surveillance data were reported by Ezhou influenza sentinel hospitals and etiological examination results were collected by network laboratory. Influenza surveillance data from 2016 to 2021 were analyzed. ResultsFrom 2016 to 2021， the percentage of ILI visits （ILI%） in Ezhou city was 2.81% and increased over years. Majority （55.55%） of ILI cases were 0‒4 years. A total of 7 716 ILI samples were examined from 2016 to 2021， of which 1 467 tested positive with a positive rate of 19.01%. Influenza A H1N1 was mainly concentrated in January-April， A H3N2 mainly in August-December， B Victoria mainly in April-July and December-March， and B Yamagata mainly in December-February. Influenza network laboratory isolated influenza virus from the 1 467 positive samples by using MDCK cells and SPF chicken embryos. The overall isolation rate was 32.78%， which was 26.93% by MDCK cells and 5.86% by SPF chicken embryos. From 2016 to 2021， a total of 13 ILI outbreaks were reported in Ezhou City. Temporally， the outbreaks mainly occurred in winter and spring. Spatially， they were mainly in primary schools， middle schools and kindergartens. ConclusionThe winter and spring are the key time period of influenza prevention and control in Ezhou City， as they are susceptible to influenza outbreaks. Children aged 0‒14 are the key population of prevention and control. Diverse subtypes of influenza virus alternate by years， which warrants continually strengthening monitoring. Additionally， certain countermeasures against COVID-19 may be recommended in the prevention and control of influenza.
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ObjectiveTo perform the analysis of influenza surveillance in Dehong from 2016 to 2020 and determine the epidemic situation of influenza and prevalent virus strains， so as to provide evidence for local influenza prevention and control. MethodsThe influenza surveillance data in Dehong Prefecture was collected from January 2016 to December 2020. Statistical analysis was conducted by descriptive epidemiological methods. ResultsA total of 4 146 samples from influenza-like illness cases were examined. The 502 specimens tested positive for influenza virus， including 311 cases with influenza A virus and 136 cases with influenza B virus， resulting in a positive rate of 12.11%. The positive rate was the highest in 2017， followed by 2019， and the lowest in 2020 （P < 0.05）. It peaked in winter and fall. Furthermore， it was the lowest among children aged 0‒4 years and the highest among adults aged 25‒59 （P < 0.001）. In addition， positive rate did not differ significantly by gender（P>0.05） ConclusionThe positive rate of influenza has decreased in Dehong since January 2020. The influenza epidemic is seasonal， mainly in fall and winter， except 2020. Influenza A virus is predominant， compared to alternating influenza B virus.
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Background and Objectives@#Fire events emit pollutants that affect both air quality and respiratory health. This paper analyzed the interrelationship of satellite-derived fire spot density and annual average particulate matter (PM₂.₅) concentrations with the incidence of respiratory diseases. @*Methodology@#Monthly cases of influenza-like illness (ILI) and pertussis for 2017-2018 in all 17 regions of the Philippines were accessed from the Department of Health (DOH) Epidemiology Bureau. Reported cases per 100,000 population in the Philippines were linked with regional fire spot density and annual mean PM₂.₅ estimates from satellite data, Visible Infrared Imaging Radiometer Suite (VIIRS) active fire data, and Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), respectively. Linear, logistic, and Poisson models were used to analyze the association between the exposure and outcome variables. @*Results and Discussion@#The highest PM₂.₅ concentrations were observed in Regions IV-A and NCR but fire spot density was relatively lower. High PM₂.₅ levels can be due to other sources in these largely urbanized regions, such as vehicular emission, among others. Similarly, results showed inconclusive association between atmospheric parameters and incidence of ILI and pertussis. Among the variables, pertussis and PM₂.₅ may have the strongest association, albeit p>0.05. Other factors contributing to the increase of disease counts may be explored including vaccine rates and case reporting. @*Conclusion@#There is insufficient evidence to show that fire events and higher PM₂.₅ levels at a regional scale increased the risk for ILI and pertussis in 2017-2018. Further studies may be explored on how satellite-derived atmospheric data can be utilized in respiratory health studies.
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Objective:To investigate the epidemiological characteristics of influenza-like illnesses (ILI) and the etiological characteristics of influenza viruses in Minhang District of Shanghai from 2010 to 2021.Methods:The surveillance data collected by influenza surveillance sentinel hospitals and the influenza laboratory network from the first week of 2010 to the 52 nd week of 2021 were used for a statistical analysis. Results:A total of 122 903 cases with ILI were reported by the national influenza surveillance sentinel hospitals in Minhang during 2010 to 2021, and the average percentage of ILI cases was 0.94%, showing an increasing trend ( P<0.001). Among them, those aged 0-4, 5-14, 15-24, 25-59 and ≥60 years accounted for 4.35%, 13.30%, 14.30%, 54.32% and 13.73%, respectively. The percentage of ILI showed obvious periodicity. The seasonal incidence of ILI peaked from December to February and from July to September. But the winter peak at the beginning of 2013 was postponed. There was no significant peak in 2021. A total of 11 625 samples were tested from 2010 to 2021, in which the detection rate of influenza viruses was 20.92% (2 432/11 625). The positive rate was 12.83% (1 492/11 625) for influenza A viruses and 8.09% (940/11 625) for influenza B viruses, indicating that the epidemic intensity caused by influenza A viruses was greater than that caused by influenza B viruses. The overall positive rates for influenza A/H3N2 virus, influenza A/H1N1 virus, influenza B/Victoria lineage and influenza B/Yamagata lineage were 9.04% (1 051/11 625), 3.79% (441/11 625), 2.69% (313/11 625) and 2.19% (255/11 625) during 2010 to 2021. The predominant circulating strains altered between influenza A and influenza B viruses in Minhang District of Shanghai during 2010 to 2019. It generally took six months for an epidemic strain to be replaced by a new one. No obvious regularity was observed in 2020 or 2021. The tendency of the incidence of ILI reported from 2010 to 2019 was basically the same as that of the positive rate of influenza viruses, while there were significant differences in 2020 and 2021. Conclusions:Influenza viruses circulated seasonally in Minhang District of Shanghai with alternating prevalent viral subtypes and the infections mostly occurred in the winter and summer seasons. During the epidemic of COVID-19, the intensity of influenza was decreased, but with the normalization of prevention and control measures, the influenza epidemic showed an obvious upward trend. Therefore, it was important to strengthen the prevention and monitoring of influenza and analyze the virus variations in time.
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Objective:To study the pathogenic spectrum of enterovirus (EV) in the samples of child influenza-like(ILI)cases in Hangzhou city .Methods:In 2019, 1 060 throat swab specimens of ILI cases were collected for serotyping of influenza virus and EVs by real-time RT-PCR. The positive rates of influenza virus and EV in spring, summer, autumn and winter were compared by chi-square test with SPSS16.0 software. Specific primers were synthesized and used to amplify the VP1 fragments of EV. PCR products were sequenced and the results were compared with the reference sequences by using Basic Local Alignment Search Tool (BLAST) to identify the serotypes of isolated EV. The clinical diagnoses of EV positive cases were classified and analyzed.Results:A total of 1 060 specimens were collected and 283(26.70%) were positive for influenza virus, 75(7.08%) were positive for EV, 3(0.28%)were positive for influenza virus and EV. The comparison of positive detection rate of spring, summer, autumn and winter showed that influenza virus were prevalent in winter and spring. EV were mostly popular in the summer months. VP1 sequences of 51 EV were successfully amplified and BLAST analysis revealed that these strains belonged to 10 serotypes, including five serotypes of EV-A species, four serotypes of EV-B species and one serotype of EV-D. The ten serotypes of EV, including coxsackievirus (CV)A2, A4, A5, A6, A9, A10, and echovirus (ECHO)7, ECHO11, ECHO18, and EV-D68 were obtained and the percentages of positive were 16.00%, 16.00%, 5.33%, 12.00%, 5.33%, 1.33%, 1.33%, 5.33%, 4.00% and 1.33%, respectively. The phylogram of EV VP1 sequence showed that 51 EV strains in Hangzhou had different degrees of variation compared with the reference strains. Acute upper respiratory tract infection was the main clinical diagnosis in EV positive children, with 44 cases (58.67%). Acute tonsillitis was followed by 14 cases (18.67%). Followed by herpetic pharyngitis, acute bronchitis, asthmatic bronchitis, pneumonia, accounting for 12.00%, 8.00%, 1.33%, 1.33%, respectively.Conclusions:EV causing influenza-like illness in children in Hangzhou in 2019 belonged to 10 serotypes, CVA2 and CVA4 were the predominant serotypes, and the positive rate of EV detection was higher in summer.
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Objective To investigate the epidemiological characteristics of influenza in Songjiang District, Shanghai during 2014-2018, and to provide scientific evidence for the prevention of influenza. Methods We collected the data including influenza-like illness(ILI)report, etiological examination and influenza outbreak in Songjiang, and further characterized the epidemic of influenza using descriptive statistics. Results Data from the sentinel hospital-based surveillance system showed two peaks of influenza incidence in winter and summer in Songjiang, in which the winter peak was more significant. The largest proportion of ILI was the age group 0-4 years(57.90%). The proportion of being positive for influenza nucleic acid was 18.44%. All principal types of influenza were prevalent in Songjiang with a certain pattern of alternative circulation, in which influenza B virus accounted for 41.18% among all the types, followed by seasonal H3(36.95%)and H1N1(21.98%). A total of 650 influenza strains were isolated. The total proportion of isolation was 67.08%, which fluctuated by year with a peak of 79.37% in 2016. Of all the 27 outbreaks of influenza, 88.89% of them were identified in primary and middle schools and 70.37% occurred in December. Conclusion Different subtypes of influenza viruses were prevalent alternatively in Songjiang during 2014-2018. The etiological results and influenza outbreaks are generally in consistent with ILI report. It warrants necessary prevention in primary and middle schools in epidemic seasons of influenza.
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Objective To analyze the distribution and epidemiological characteristics of influenza pathogens in Huai’an City from 2017-2019, and to provide a scientific basis for prevention and control of influenza. Methods The influenza-like illness (ILI) and outbreaks data was collected from China Influenza Surveillance Information System from 2017 to 2019. A descriptive analysis method was used to analyze the influenza data. Results A total of 103 082 ILI cases were reported in Huai’an City from 2017 to 2019, accounting for 8.96% of the total outpatient and emergency department visits. Winter and spring were the seasons for the high incidence of influenza, and children under 15 years old were the key population with high incidence. A total of 37 influenza outbreaks occurred in the city, with 774 reported cases. The epidemics mainly occurred in kindergartens, elementary schools, and junior high schools. There were 6,730 samples tested in the laboratory, 1,093 were positive for nucleic acid test, and the positive rate was 16.24%. Of the 1,093 positive samples, 417 were tested positive for H1N1 type, accounting for 38.15%; 251 were positive for seasonal H3 type, accounting for 22.96%; 274 were positive for Victoria subtype, accounting for 25.07%; and 151 were positive for Yamagata subtype, accounting for 13.82%. The types of dominant influenza strains alternated, and sometimes several types of influenza viruses coexisted. Conclusion Influenza often occurs in schools and has obvious seasonality. It is recommended that high-risk groups be vaccinated with quadrivalent influenza vaccine.
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Objective@#To evaluate the feasibility of autoregressive integrated moving average with explanatory variables ( ARIMAX ) model including meteorological factors on the prediction of influenza-like illness ( ILI ), so as to provide a basis for the monitoring and early warning of influenza.@*Methods@#The ILI data reported by four sentinel hospitals in Yuhang District of Hangzhou from the 1st week of 2014 to the 26th week of 2018 was collected, as well as the meteorological data during the same period. The ARIMAX model was established using the percentage of ILI cases in total outpatients ( ILI% ) data from the 1st week of 2014 to the 52nd week of 2017 and the meteorological factors selected by Lasso regression model. The ILI% from the 1st to 26th week of 2018 was predicted and compared with the actual values to verify the ARIMAX model.@*Results@#From the 1st week of 2014 to the 26th week of 2018, a total of 60 419 cases of ILI were reported by the four sentinel hospitals of Yuhang District, with ILI% of 1.29%. Lasso regression analysis showed that there was a positive correlation between weekly average absolute humidity and ILI% ( r=27.769 ), and a negative correlation between weekly average temperature and ILI% ( r=-0.117 ). The ARIMAX (1, 0, 0) ( 1, 0, 0 )12 with weekly average temperature and absolute humidity was selected as the optimal model, with the Bayesian information criterion (BIC) value of 81.30 and the mean absolute percentage error (MAPE) value of 15.77%. The MAPE value of the ARIMAX model predicting the ILI% from 1st to 26th week of 2018 were 43.75%.@*Conclusion@#The ARIMAX model including meteorological factors can be used to predict the prevalence of ILI, but the accuracy needs to be promoted.
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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.
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ObjectiveTo analyze the epidemiological characteristics and incidence trend of influenza-like illness in Xuhui District from 2010 to 2019， in order to understand the patterns of influenza epidemic of Xuhui District，and to provide evidence for the prevention and control of influenza in the future. MethodsSurveillance data of influenza-like illness （ILI） in Xuhui District from 2010 to 2019 were collected from the National Influenza Surveillance System for statistical description and trend analysis. ResultsFrom 2010 to 2019， the overall proportion of influenza-like illness was 0.54%. The annual proportions of ILI were between 0.35%~1.14%．The majority of cases were reported in age group of 25~59， accounted for 54.50% of the total ILI. A total of 9 053 throat swab specimens from ILI patients were collected and tested， from which 2 137 specimens were positive， with a positive rate of 23.61%. The most frequent subtype of influenza virus detected was influenza A virus （accounting for 67.62%）. The proportion of ILI and the positive rate of influenza virus nucleic acid detection reached the peak in summer and winter over time. There was a positive correlation between the proportion of ILI and the positive rate of influenza （r=0.666， P<0.01）. From 2010 to 2019， both ILI% and nucleic acid positive rate of influenza virus showed a downward trend. ConclusionThe incidence of influenza shows a downward trend in Xuhui District， with two peaks in summer and winter. The most susceptible individuals are in 25~59 age group. The dominant strains of influenza virus alternate regularly， influenza A（H3N2） dominate the summer epidemic peak while the epidemic peak in winter is dominated by influenza A（H1N1） and influenza B.
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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.
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ObjectiveTo analyze the epidemiological characteristics and incidence trend of influenza-like illness in Xuhui District from 2010 to 2019， in order to understand the patterns of influenza epidemic of Xuhui District，and to provide evidence for the prevention and control of influenza in the future. MethodsSurveillance data of influenza-like illness （ILI） in Xuhui District from 2010 to 2019 were collected from the National Influenza Surveillance System for statistical description and trend analysis. ResultsFrom 2010 to 2019， the overall proportion of influenza-like illness was 0.54%. The annual proportions of ILI were between 0.35%~1.14%．The majority of cases were reported in age group of 25~59， accounted for 54.50% of the total ILI. A total of 9 053 throat swab specimens from ILI patients were collected and tested， from which 2 137 specimens were positive， with a positive rate of 23.61%. The most frequent subtype of influenza virus detected was influenza A virus （accounting for 67.62%）. The proportion of ILI and the positive rate of influenza virus nucleic acid detection reached the peak in summer and winter over time. There was a positive correlation between the proportion of ILI and the positive rate of influenza （r=0.666， P<0.01）. From 2010 to 2019， both ILI% and nucleic acid positive rate of influenza virus showed a downward trend. ConclusionThe incidence of influenza shows a downward trend in Xuhui District， with two peaks in summer and winter. The most susceptible individuals are in 25~59 age group. The dominant strains of influenza virus alternate regularly， influenza A（H3N2） dominate the summer epidemic peak while the epidemic peak in winter is dominated by influenza A（H1N1） and influenza B.