2018—2020年珠海市学校流感样病例暴发疫情流行特征及影响因素分析

目的 分析珠海市2018—2020年学校流感样病例暴发疫情的流行特征和影响疫情规模的相关因素,为制定防控策略提供依据。方法 采用描述流行病学方法分析学校流感样病例暴发疫情流行特征,采用χ2检验和Logistic回归分析疫情规模的影响因素。结果 2018—2020年珠海市学校累计报告67起流感样病例暴发疫情,累计发病人数1 746例。发病高峰为每年3月—6月和12月—次年1月,主要发生在小学,流感样病例的发病年龄高峰为6～8岁。病原体主要为B型、A(H3N2)亚型和A(H1N1)亚型流感病毒。暴发疫情涉及病例咽痛发生率>50%的学校发生大规模流感样病例暴发疫情的风险是咽痛发生率≤50%学校的4.308倍(95%CI:1.100～16.864)。结论 2018—2020年珠海市学校流感样病例暴发疫情主要集中在冬春季节的小学,高咽痛发生率是学校发生大规模疫情流感样病例暴发疫情的危险因素。     

Decomposing Racial and Ethnic Disparities in Nursing Home Influenza Vaccination

ObjectivesQuantify how observable characteristics contribute to influenza vaccination disparities among White, Black, and Hispanic nursing home (NH) residents.DesignRetrospective cohort.Setting and ParticipantsShort- and long-stay U.S. NH residents aged ≥65 years.MethodsWe linked Minimum Data Set (MDS) and Medicare data to LTCFocUS and other facility data. We included residents with 6-month continuous enrollment in Medicare and an MDS assessment between October 1, 2013, and March 31, 2014. Residents were classified as short-stay (<100 days in NH) or long-stay (≥100 days in NH). We fit multivariable logistic regression models to assess the relationships between 27 resident and NH-level characteristics and receipt of influenza vaccination. Using nonlinear Oaxaca-Blinder decomposition, we decomposed the disparity in influenza vaccination between White versus Black and White versus Hispanic NH residents. Analyses were repeated separately for short- and long-stay residents.ResultsOur study included 630,373 short-stay and 1,029,593 long-stay residents. Proportions vaccinated against influenza included 67.2% of White, 55.1% of Black, and 54.5% of Hispanic individuals among short-stay residents and 84.2%, 76.7%, and 80.8%, respectively among long-stay residents. Across 4 comparisons, the crude disparity in influenza vaccination ranged from 3.4 to 12.7 percentage points. By equalizing 27 prespecified characteristics, these disparities could be reduced 37.7% to 59.2%. Living in a predominantly White facility and proxies for NH quality were important contributors across all analyses. Characteristics unmeasured in our data (eg, NH staff attitudes and beliefs) may have also contributed significantly to the disparity.Conclusions and ImplicationsThe racial/ethnic disparity in influenza vaccination was most dramatic among short-stay residents. Intervening on factors associated with NH quality would likely reduce these disparities; however, future qualitative research is essential to explore potential contributors that were unmeasured in our data and to understand the degree to which these factors contribute to the overall disparity in influenza vaccination.     

Highly Pathogenic Avian Influenza A(H5N8) Virus Spread by Short- and Long-Range Transmission,France, 2016–17

We detected 3 genotypes of highly pathogenic avian influenza A(H5N8) virus in France during winter 2016–17. Genotype A viruses caused dramatic economic losses in the domestic duck farm industry in southwestern France. Our phylogenetic analysis suggests that genotype A viruses formed 5 distinct geographic clusters in southwestern France. In some clusters, local secondary transmission might have been started by a single introduction. The intensity of the viral spread seems to correspond to the density of duck holdings in each production area. To avoid the introduction of disease into an unaffected area, it is crucial that authorities limit the movements of potentially infected birds.     

COVID-19 and Infant Hospitalizations for Seasonal Respiratory Virus Infections,New Zealand, 2020

In March 2020, a national elimination strategy for coronavirus disease was introduced in New Zealand. Since then, hospitalizations for lower respiratory tract infection among infants <2 years of age and cases of respiratory syncytial or influenza virus infection have dramatically decreased. These findings indicate additional benefits of coronavirus disease control strategies.     

Determinants of biosecurity practices in French duck farms after a H5N8 Highly Pathogenic Avian Influenza epidemic: The effect of farmer knowledge,attitudes and personality traits

Biosecurity is crucial for infectious disease prevention, more importantly in the absence of vaccination. The need for improving the implementation of biosecurity practices was highlighted in French duck farms following the 2016–2017 H5N8 Highly Pathogenic Avian Influenza (HPAI) epidemic. Farmers have multiple reasons for not implementing biosecurity practices: external (time, money) and internal (socio‐psychological). The purpose of this study was to determine how sets of socio‐psychological factors (i.e. knowledge on biosecurity and avian influenza transmission, attitudes, personality traits, social background) affect the adoption of on‐farm biosecurity practices. Biosecurity practices and socio‐psychological determinants were assessed during 127 duck farm visits, in South West France, using both questionnaires and on‐farm observations. Factorial analysis of mixed data (FAMD) and hierarchical clustering analysis (HCA) identified three groups of farmers with different socio‐psychological profiles: the first group was characterized by minimal knowledge, negative attitudes towards biosecurity, little social pressure and a low level of conscientiousness. The second group was characterized by more extensive experience in poultry production, higher stress and social pressure. The third group was characterized by less experience in poultry production, better knowledge and positive attitudes towards biosecurity, increased self‐confidence and orientation towards action. The first group had a significantly lower adoption of biosecurity measures than the two other groups. A better understanding of the factors involved in farmers' decision‐making could improve the efficiency of interventions aiming at improving and maintaining the level of on‐farm biosecurity in the duck industry.     

2016—2019 年天津市河北区流行性感冒监测分析

目的 了解 2016—2019年天津市河北区流感流行特征,为有效防控流感提供相应科学依据。方法 对 2016—2019年天津市河北区流感样病例(Influenza-likecases,ILI)监测资料、病原学监测数据及暴发疫情信息进行分析。结果 2016—2019 年共采集IL咽拭子标本 2 962份,流感病毒核酸检测阳性标本为 715份,阳性率为 24.14%;2016—2019年共报告流感样病例暴发疫情 10起,均发生在中小学校。2016—2019 年天津市河北区流感样病例百分比 (IL%)在每年 11 月—次年 2 月出现一个高峰,呈现明显的季节性特征;2016—2019 年流感病原监测结果显示,天津市河北区流行毒株以甲型 H3N2 型和甲型 H1N1型交替出现为主,2017 年甲型与乙型 Yamagata 系混合流行,2019 年甲型 H3N2 型呈优势毒株。结论 2016—2019 年天津市河北区流感病毒以甲型 H3N2 型和甲型 H1N1 型为主,每年的流行毒株各不相同,呈交替或混合流行。应加强监测和流感防控并提高重点人群流感疫苗接种率。     

Cost-effectiveness analysis of quadrivalent seasonal influenza vaccines in Beijing: A modeling analysis

BackgroundSince 2007, Beijing has offered a free trivalent influenza vaccine (TIV) for residents aged ≥ 60 years and school students. The quadrivalent influenza vaccine (QIV) was administered to school children in 2018 and will be administered to elderly adults in the future. In addition, health care workers (HCWs) who are involved in the prevention and control of COVID-19 were included in the program in 2020. This study aimed to analyze the cost-effectiveness of a comprehensive list of combined strategies of TIV and QIV for school children, elderly adults, and HCWs to identify the most cost-effective strategy.MethodsA decision tree was developed to compare 1-year outcomes of TIV vs. QIV in three risk groups: school children, elderly adults, and HCWs. The outcome was incremental cost per quality-adjusted life-year (QALY). Probabilistic sensitivity analyses and scenario analyses were developed to assess the robustness of the results.ResultsFrom the perspective of society, this study found that the introduction of QIVs can be cost-effective for any and all targeted groups with a willingness-to-pay threshold of 3-fold GDP per capita. Among all programs, program H (all school children, elderly adults, and HCWs received the QIV) showed a 79% probability of being cost-effective with an incremental cost-effectiveness ratio (ICER) of 13,580 (95% CI: 13,294, 13,867) US$/QALY and was the preferred option in the base case scenario.ConclusionThe introduction of QIVs to school children, elderly adults, or HCWs is likely to be cost-effective, either separately or collectively. The introduction of QIV to school children, elderly adults, and health care workers simultaneously showed the highest probability of being cost-effective and was the preferred option.     

禽流感病毒核蛋白单克隆抗体的制备及部分特性鉴定

目的：制备抗禽流感病毒（AIV）核蛋白（NP）的单克隆抗体（mAb）并进行特性鉴定。方法：分别用甲醛灭活的和TritonX-100裂解的AIV H9N2及AIVNP基因的原核表达产物免疫BALB／c小鼠。经细胞融合、间接ELISA筛选及克隆化，建立能稳定分泌抗AIV NP mAb的杂交瘤细胞株。mAb的效价采用间接ELISA测定，用交义反应试验及间接免疫荧光染色法检测mAb的特异性。结果：经细胞融合、筛选及克隆化，间接ELISA法测定，mAb共得到6株能稳定分泌抗禽流感病毒NPmAb的杂交瘤细胞株，分别命名为4F4、1C3、1G11、1C2、1D10及2E7。1G11、1D10腹水的ELISA效价最高，分别为2^-13和2^-14。交叉反应试验及间接免疫荧光染色检测表明，两株mAb的特异性良好。结论：其获得6株抗AIVNP的mAb，其中2株mAb1C11和1D10的效价最高，特异性良好，为AIV的研究及快速诊断方法的建立奠定了基础。     

Clonal composition and persistence of antigen-specific circulating T follicular helper cells

T follicular helper (T_FH) cells play an essential role in promoting B cell responses and antibody affinity maturation in germinal centers (GC). A subset of memory CD4⁺ T cells expressing the chemokine receptor CXCR5 has been described in human blood as phenotypically and clonally related to GC T_FH cells. However, the antigen specificity and relationship of these circulating T_FH (cT_FH) cells with other memory CD4⁺ T cells remain poorly defined. Combining antigenic stimulation and T cell receptor (TCR) Vβ sequencing, we found T cells specific to tetanus toxoid (TT), influenza vaccine (Flu), or Candida albicans (C.alb) in both cT_FH and non-cT_FH subsets, although with different frequencies and effector functions. Interestingly, cT_FH and non-cT_FH cells specific for C.alb or TT had a largely overlapping TCR Vβ repertoire while the repertoire of Flu-specific cT_FH and non-cT_FH cells was distinct. Furthermore, Flu-specific but not C.alb-specific PD-1⁺ cT_FH cells had a “GC T_FH-like” phenotype, with overexpression of IL21, CXCL13, and BCL6. Longitudinal analysis of serial blood donations showed that Flu-specific cT_FH and non-cT_FH cells persisted as stable repertoires for years. Collectively, our study provides insights on the relationship of cT_FH with non-cT_FH cells and on the heterogeneity and persistence of antigen-specific human cT_FH cells.