Early vaccine effectiveness estimates against medically attended laboratory-confirmed influenza based on influenza surveillance, Beijing, China, 2024/25 season.

We estimated early influenza vaccine effectiveness (VE) for the 2024/25 season in outpatients, in Beijing using a test-negative design. A(H1N1)pdm09 dominated (99.3%), all sequenced strains (n = 38) clustered in clade 6B.

Vaccine effectiveness against influenza B/Victoria-associated medically attended influenza-like illness: Beijing, China, 2021-2022 influenza season.

Influenza B/Victoria viruses predominated during the 2021-2022 influenza season in Beijing, China, unlike most northern hemisphere countries, likely due to reduced international travel. We estimated influenza vaccine effectiveness (VE) against the B/Victoria lineage to provide a more comprehensive evaluation of 2021-2022 influenza VE. Between October 2021 and April 2022, patients aged ≥6 months with influenza-like illness (ILI) visiting outpatient departments in Beijing's influenza virological surveillance system were enrolled.

Moderate effectiveness of influenza vaccine in outpatient settings: A test-negative study in Beijing, China, 2023/24 season.

Introduction: The objective of our study was to estimate the influenza vaccine effectiveness for 2023/24 epidemic of co-circulating influenza A(H3N2) and B(Victoria) viruses in Beijing, China.

Methods: The surveillance-based study included all swabbed patients through influenza virological surveillance in Beijing, between October 2023 and March 2024. A Test-Negative Design(TND) was used to estimate influenza vaccine effectiveness(VE) against medically- attended laboratory-confirmed influenza in outpatient settings, also calculated the influenza vaccination rate(IVR).

Influenza Vaccine Effectiveness against Influenza A-Associated Outpatient and Emergency-Department-Attended Influenza-like Illness during the Delayed 2022-2023 Season in Beijing, China.

Background: During the 2022-2023 influenza season, the influenza activities in most regions of China were postponed, including Beijing. The unusually delayed influenza epidemic posed a challenge to the effectiveness of the influenza vaccine.

Methods: Using the test-negative design, we evaluated influenza vaccine effectiveness (VE) during the 2022-2023 influenza season against influenza A-associated outpatient and emergency-department-attended influenza-like illness (ILI) in Beijing, China, from 9 January to 30 April 2023.

An Intense Out-of-Season Rebound of Influenza Activity After the Relaxation of Coronavirus Disease 2019 Restrictions in Beijing, China.

Background: The aim of this study was to investigate the changes of epidemic characteristics of influenza activity pre- and post-coronavirus disease 2019 (COVID-19) in Beijing, China.

Methods: Epidemiologic data were collected from the influenza surveillance system in Beijing. We compared epidemic intensity, epidemic onset and duration, and influenza transmissibility during the 2022-2023 season with pre-COVID-19 seasons from 2014 to 2020.

Using an influenza surveillance system to estimate the number of SARS-CoV-2 infections in Beijing, China, weeks 2 to 6 2023.

With COVID-19 public health control measures downgraded in China in January 2023, reported COVID-19 case numbers may underestimate the true numbers after the SARS-CoV-2 Omicron wave. Using a multiplier model based on our influenza surveillance system, we estimated that the overall incidence of SARS-CoV-2 infections was 392/100,000 population in Beijing during the 5 weeks following policy adjustment. No notable change occurred after the Spring Festival in early February.

The role of absolute humidity in influenza transmission in Beijing, China: risk assessment and attributable fraction identification.

To assess the impact of absolute humidity on influenza transmission in Beijing from 2014 to 2019, we estimated the influenza transmissibility via the instantaneous reproduction number (R), and evaluated its nonlinear exposure-response association and delayed effects with absolute humidity by using the distributed lag nonlinear model (DLNM). Attributable fraction (AF) of R due to absolute humidity was calculated. The result showed a significant M-shaped relationship between R and absolute humidity.

Role of presymptomatic transmission of COVID-19: evidence from Beijing, China.

Background: The presymptomatic transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented in limited clusters, and it is predicted through modelling. However, there is a lack of evidence from observations with a large sample size.

Methods: We used data from meticulous contact tracing of people exposed to cases of SARS-CoV-2 to estimate the proportion of cases that result from the presymptomatic transmission of the virus in Beijing during January 2020 and February 2020.

Avian influenza A (H9N2) virus infections among poultry workers, swine workers, and the general population in Beijing, China, 2013-2016: A serological cohort study.

Background: Few studies have reported on the seroprevalence of antibodies against avian influenza A (H9N2) virus and the incidence of these infections in the northern China and among swine workers.

Methods: We conducted a serological cohort study among people working with poultry or swine or the general population in Beijing, China. It comprised four cross-sectional serological surveys in November 2013, April 2014, April 2015, and April 2016.

Reduction of influenza A(H3N2)-associated symptoms by influenza vaccination in school aged-children during the 2014-2015 winter season dominated by mismatched H3N2 viruses.

Background: Little is known about the vaccine effectiveness (VE) in attenuating the influenza-associated symptoms in children during the 2014-2015 influenza season in Beijing, China, in which there was a mismatch between the vaccine and circulating strain.

Methods: This study included 210 laboratory-confirmed influenza cases among children, who were enrolled in 2014, from November 1 to December 31. Standard demographic information and clinical symptoms were recorded.

Influenza vaccine effectiveness in preventing laboratory-confirmed influenza in outpatient settings: A test-negative case-control study in Beijing, China, 2016/17 season.

Background: The objective of this study was to estimate influenza vaccine effectiveness (VE) for the 2016/17 epidemic of co-circulating influenza A(H1N1)pdm09 and A(H3N2) viruses in Beijing, the capital of China.

Methods: The surveillance-based study included all swabbed patients through influenza virological surveillance, between November 2016 and April 2017. A test-negative case-control design was used to estimate influenza VE against medically-attended laboratory-confirmed influenza in outpatient settings.

Moderate influenza vaccine effectiveness against influenza A(H1N1)pdm09 virus and low effectiveness against A(H3N2) virus among older adults during 2013-2014 influenza season in Beijing, China.

Background: Since 2007, trivalent inactivated influenza vaccine has been provided free-of-charge to older adults aged ≥60 years in Beijing, China, but the data regarding influenza vaccine effectiveness (VE) among these people are very limited so far. We sought to estimate influenza VE against medically-attended laboratory-confirmed influenza illness among older adults during the 2013-2014 season.

Methods: The influenza-like illness (ILI) patients aged 60 years and older who participated in the influenza virological surveillance of Beijing during 2013-2014 influenza season were recruited in this study.

Influenza vaccination in preventing outbreaks in schools: A long-term ecological overview.

Influenza vaccination is the most effective way to reduce the incidence of influenza infections. However, the role of influenza vaccination, such as school-based influenza vaccination, in preventing the influenza outbreaks in schools remains unclear now. In this study, a total of 286 school febrile outbreaks involving 6863 cases in the Beijing area from September 1, 2006 to March 31, 2017 were analyzed.

Influenza vaccine effectiveness against medically attended influenza illness in Beijing, China, 2014/15 season.

Influenza vaccination is the most effective way of preventing influenza infections but its coverage is extremely low in China. Poor influenza vaccine effectiveness (VE) was reported in the 2014/15 season in some Northern Hemisphere countries with a predominance of H3N2 viruses belonging to the 3C.2a clade.

H7N9 not only endanger human health but also hit stock marketing.

Objective: This study aims to discuss the correlation between daily reported H7N9 cases and stock price indices in China.

Methods: Information on daily reported H7N9 cases and stock market sectors indices between February 19, 2013 and March 31, 2014 were collected. A distributed lag non-linear model was used to describe the variation trend for the stock indices.

Influenza Vaccine Effectiveness in Preventing Influenza Illness Among Children During School-based Outbreaks in the 2014-2015 Season in Beijing, China.

Background: Little is known about vaccine effectiveness (VE) against nonmedically attended A(H3N2) influenza illness during 2014-2015 when the vaccine component appeared to be a poor match with circulating strains.

Methods: Forty-three eligible school influenza outbreaks in Beijing, China, from November 1, 2014, to December 31, 2014, were included in this study. The VE of 2014-2015 trivalent inactivated influenza vaccine (IIV3) was assessed in preventing laboratory-confirmed influenza among school-age children through a case-control design, using asymptomatic controls.

Avian influenza A(H7N9) and (H5N1) infections among poultry and swine workers and the general population in Beijing, China, 2013-2015.

Although several studies have reported seroprevalences of antibody against avian influenza A(H7N9) virus among poultry workers in southern China, results have varied and data in northern China are scarce. To understand risks of H7N9 and H5N1 virus infections in northern China, a serological cohort study was conducted. Poultry workers, swine workers and the general population in Beijing, China, were evaluated through three surveys in November 2013, April 2014 and April 2015.

Estimated burden of group a streptococcal pharyngitis among children in Beijing, China.

Background: Burden of Group A streptococcus (GAS) pharyngitis is scarce in developing countries, still unknown in China. The objective of this study was to determine the incidence of clinical cases of pharyngitis and GAS culture-positive pharyngitis, and their outpatient visits among children aged 0-14 years in Beijing, the capital of China.

Methods: Multiplier model was used to estimate the numbers of pharyngitis cases, based on reported numbers of clinical cases and GAS culture-positive rates from GAS surveillances in Beijing, consultation rate, population coverage of GAS surveillances, sampling success rate, and test sensitivity of GAS culture from previous studies, surveys and surveillances.

Infectious disease-specific health literacy in Tibet, China.

This study was aimed to develop an instrument to assess infectious disease-specific health literacy (IDSHL) in the general population of Tibet, China and identify the association between IDSHL and reported infectious disease-related symptoms. A survey using a standardized questionnaire, which included 25 questions on knowledge, behaviors and skills regarding infectious diseases, was conducted in the general population of Tibet, China between September 2011 and November 2011. The 25 questions formed the index system of the instrument assessing IDSHL (total scores: 25 scores).

Hygiene Behaviors Associated with Influenza-Like Illness among Adults in Beijing, China: A Large, Population-Based Survey.

The objective of this study was to identify possible hygiene behaviors associated with the incidence of ILI among adults in Beijing. In January 2011, we conducted a multi-stage sampling, cross-sectional survey of adults living in Beijing using self-administered anonymous questionnaires. The main outcome variable was self-reported ILI within the past year.

Technical guidelines for the application of seasonal influenza vaccine in China (2014-2015).

Influenza, caused by the influenza virus, is a respiratory infectious disease that can severely affect human health. Influenza viruses undergo frequent antigenic changes, thus could spread quickly. Influenza causes seasonal epidemics and outbreaks in public gatherings such as schools, kindergartens, and nursing homes.

Cluster of human infections with avian influenza A (H7N9) cases: a temporal and spatial analysis.

Objectives: This study aims to describe the spatial and temporal characteristics of human infections with H7N9 virus in China using data from February 2013 to March 2014 from the websites of every province's Population and Family Planning Commission.

Methods: A human infection with H7N9 virus dataset was summarized by county to analyze its spatial clustering, and by date of illness onset to analyze its space-time clustering using the ESRI® Geographic Information System (GIS) software ArcMap™ 10.1 and SatScan.

The impact of temperature and humidity measures on influenza A (H7N9) outbreaks-evidence from China.

Objectives: To examine the non-linear effects of meteorological factors on the incidence of influenza A H7N9 and to determine what meteorological measure, and on which day preceding symptom onset, has the most significant effect on H7N9 infection.

Methods: We applied a zero truncated Poisson regression model incorporating smoothed spline functions to assess the non-linear effect of temperature (maximum, minimum, and daily difference) and relative humidity on H7N9 human case numbers occurring in China from February 19, 2013 to February 18, 2014, adjusting for the effects of age and gender.

Results: Both daily minimum and daily maximum temperature contributed significantly to human infection with the influenza A H7N9 virus.