Polio infrastructure strengthened disease outbreak preparedness and response in the WHO African Region

IntroductionThe continuous deployments of polio resources, infrastructures and systems for responding to other disease outbreaks in many African countries has led to a number of lessons considered as best practice that need to be documented for strengthening preparedness and response activities in future outbreaks.MethodsWe reviewed and documented the influence of polio best practices in outbreak preparedness and response in Angola, Nigeria and Ethiopia. Data from relevant programmes of the WHO African Region were also analyzed to demonstrate clearly the relative contributions of PEI resources and infrastructure to effective disease outbreak preparedness and response.ResultsPolio resources including, human, financial, and logistic, tool and strategies have tremendously contributed to responding to diseases outbreaks across the African region. In Angola, Nigeria and Ethiopia, many disease epidemics including Marburg Hemorrhagic fever, Dengue fever, Ebola Virus Diseases (EVD), Measles, Anthrax and Shigella have been controlled using existing polio Eradication Initiatives resources. Polio staffs are usually deployed in occasions to supports outbreak response activities (coordination, surveillance, contact tracing, case investigation, finance, data management, etc.). Polio logistics such vehicles, laboratories were also used in the response activities to other infectious diseases. Many polio tools including micro planning, dashboard, guidelines, SOPs on preparedness and response have also benefited to other epidemic-prone diseases. The Countries’ preparedness and response plan to WPV importation as well as the Polio Emergency Operation Center models were successfully used to develop, strengthen and respond to many other diseases outbreak with the implication of partners and the strong leadership and ownership of governments. This review has important implications for WHO/AFRO initiative to strengthening and improving disease outbreak preparedness and responses in the African Region in respect to the international health regulations core capacities.     

Projecting the impact of a two-dose COVID-19 vaccination campaign in Ontario,Canada

BackgroundA number of highly effective COVID-19 vaccines have been developed and approved for mass vaccination. We evaluated the impact of vaccination on COVID-19 outbreak and disease outcomes in Ontario, Canada.MethodsWe used an agent-based transmission model and parameterized it with COVID-19 characteristics, demographics of Ontario, and age-specific clinical outcomes. We implemented a two-dose vaccination program according to tested schedules in clinical trials for Pfizer-BioNTech and Moderna vaccines, prioritizing healthcare workers, individuals with comorbidities, and those aged 65 and older. Daily vaccination rate was parameterized based on vaccine administration data. Using estimates of vaccine efficacy, we projected the impact of vaccination on the overall attack rate, hospitalizations, and deaths. We further investigated the effect of increased daily contacts at different stages during vaccination campaigns on outbreak control.ResultsMaintaining non-pharmaceutical interventions (NPIs) with an average of 74% reduction in daily contacts, vaccination with Pfizer-BioNTech and Moderna vaccines was projected to reduce hospitalizations by 27.3% (95% CrI: 22.3% − 32.4%) and 27.0% (95% CrI: 21.9% − 32.6%), respectively, over a one-year time horizon. The largest benefits of vaccination were observed in preventing deaths with reductions of 31.5% (95% CrI: 22.5% − 39.7%) and 31.9% (95% CrI: 22.0% − 41.4%) for Pfizer-BioNTech and Moderna vaccines, respectively, compared to no vaccination. We found that an increase of only 10% in daily contacts at the end of lockdown, when vaccination coverage with only one dose was 6%, would trigger a surge in the outbreak. Early relaxation of population-wide measures could lead to a substantial increase in the number of infections, potentially reaching levels observed during the peak of the second wave in Ontario.ConclusionsVaccination can substantially mitigate ongoing COVID-19 outbreaks. Sustaining population-wide NPIs, to allow for a sufficient increase in population-level immunity through vaccination, is essential to prevent future outbreaks.     

Quantification of SARS-CoV-2 spike and nucleocapsid proteins using isotope dilution tandem mass spectrometry

The emergence and subsequent global outbreak of the novel coronavirus SARS-CoV-2 prompted our laboratory to launch efforts to develop methods for SARS-CoV-2 antigen detection and quantification. We present an isotope dilution mass spectrometry method (IDMS) for rapid and accurate quantification of the primary antigens, spike and nucleocapsid proteins. This IDMS method utilizes liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze sample tryptic digests for detection and quantification of selected conserved peptides of SARS-CoV-2 spike and nucleocapsid proteins. The IDMS method has the necessary attributes to be successfully utilized for accurate quantification in SARS-CoV-2 protein-based vaccines and as targets of rapid diagnostic tests. Absolute quantification was achieved by quantifying and averaging 5 peptides for spike protein (3 peptides in the S1 subunit and 2 peptides in the S2 subunit) and 4 peptides for nucleocapsid protein. The overall relative standard deviation of the method was 3.67% for spike protein and 5.11% for nucleocapsid protein. IDMS offers speed (5 h total analysis time), sensitivity (LOQ; 10 fmol/µL) and precision for quantification of SARS-CoV-2 spike and nucleocapsid proteins.     

Effectiveness of typhoid conjugate vaccine in Zimbabwe used in response to an outbreak among children and young adults: A matched case control study

BackgroundZimbabwe suffers from regular outbreaks of typhoid fever (TF), worse since 2017. Most cases were in Harare and a vaccination campaign with Typhoid Conjugate Vaccine (TCV) was conducted in March 2019. The vaccine effectiveness (VE) was assessed against culture-confirmed S. Typhi in children six months to 15 years and in individuals six months to 45 years in Harare.MethodsA matched case-control study was conducted in three urban suburbs of Harare targeted by the TCV vaccination campaign. Suspected TF cases were enrolled prospectively in four health facilities and were matched to facility (1:1) and community (1:5) controls.FindingsOf 504 suspected cases from July 2019 to March 2020, 148 laboratory-confirmed TF cases and 153 controls confirmed-negative were identified. One hundred and five (47 aged six months to 15 years) cases were age, sex, and residence matched with 105 facility-based controls while 96 cases were matched 1:5 by age, sex, and immediate-neighbour with 229 community controls.The adjusted VE against confirmed TF was 75% (95%CI: 1–94, p = 0.049) compared to facility controls, and 84% (95%CI: 57–94, p < 0.001) compared to community controls in individuals six months to 15 years. The adjusted VE against confirmed TF was 46% (95%CI: 26–77, p = 0.153) compared to facility controls, and 67% (95%CI: 35–83, p = 0.002) compared to community controls six months to 45 years old.InterpretationThis study confirms that one vaccine dose of TCV is effective to control TF in children between six months and 15 years old in an African setting.     

Two outbreaks of typhoid fever related to the war in Bosnia and Herzegovina

Two outbreaks of typhoid fever caused by Salmonella typhi of the same phagotype (A, biotype II) and antibiotic susceptibility are reported. Both occurred during the war in Bosnia and Herzegovina. The first outbreak appeared among the refugees from the town of Jajce. The second outbreak appeared among the inhabitants in the village of Vidosi near Livno. This report describes main clinical, epidemioloigcal and laboratory findings for 22 patients treated in Split University Hospital, Croatia, in the period November 1992–January 1993. Possible epidemiological connections between those two outbreaks are discussed.     

泉州市2003年多起麻疹爆发流行病学调查分析

目的　通过分析麻疹爆发流行病学特征及发生原因 ,指导麻疹防制工作 ,加速控制麻疹进程。方法　对爆发调查和疫情资料进行描述流行病学分析 ,采用酶联免疫吸附试验 (ELISA)捕捉法检测麻疹IgM、IgG抗体 ,应用SPSS统计软件统计分析。结果　在 5个县 (市、区 )发生 1 0起麻疹爆发 ,爆发分学校 (幼儿园 )型、城镇工业区型、农村散居型 ,学校 (幼儿园 )型占 71. 6 %;主要集中在 5～ 6月 ;本地儿童占 6 8.1 %,流动儿童占 3 1 9%;4～ 9岁占73. 6 %;有麻疹疫苗 (MV)接种史的占 4 1.7%;多数病例有典型的临床症状 ;有 7起爆发经实验室确诊。对 6 4 9名 1～ 1 5岁健康人群进行麻疹IgG抗体监测 ,各年龄组抗体阳性率均 >85 %,几何平均滴度 (GMT)均 >1 :80 0。实施MV应急接种或查漏补种 ,疫情很快得到有效控制。结论　麻疹爆发是影响泉州市麻疹疫情的主要因素 ,流动儿童麻疹爆发在麻疹爆发中具有重要意义 ,预防和控制麻疹爆发是目前加速控制麻疹的主要任务     

政和县发热出疹性疾病爆发的流行病学特征与控制策略

目的为进一步降低政和县麻疹发病率，对发热出疹性疾病（RFIs）爆发疫情进行流行病学特征分析，并探讨RFIs的防控措施。方法对政和县自2000年以来6起Rns爆发疫情进行流行病学调查，采集病例的急性期血清检测麻疹、风疹IgM抗体。结果6起RFIs爆发经血清学证实：1起为麻疹爆发，5起为风疹爆发。RFIs的发病高峰季节为春季。乡、村二级医疗单位麻疹监测系统不敏感及血清学检测结果报告时间较长等延误对RFIs爆发疫情控制措施的及时落实。结论麻诊接种率高，复种年龄提前的地区麻疹发病基本处于散发状态，RFIns爆发以学校风疹为主，有条件的县级疾控单位应建立麻疹血清学诊断实验室，加大乡、村二级医疗单位疫情报告监督力度，提高监测系统敏感性，把风疹纳入常规免疫接种，可加速控制麻疹和减少风疹的爆发。     

杭州市流感暴发疫情罹患率相关因素多元回归分析

目的了解杭州市流感暴发疫情罹患率的相关因素。方法收集2004年1月至2006年4月杭州市流感暴发疫情资料,应用描述性流行病学和多元回归分析方法分析暴发疫情及流行相关因素。结果2004年1月至2006年4月杭州市共发生9起流感暴发疫情,平均罹患率为7.65%;病例主要分布于7-14岁的小学生,多发于2-4月份;住校生罹患率与走读生罹患率存在显著性差异（χ^2=78.68,P〈0.005）;以罹患率Y为应变量进行多元回归分析,有5个因素,X2（首例与高峰值时间间隔）、X3（流行时限）、X4（首例与报告时间时间间隔）、X5（单位城乡分布）、X6（单位等级）进入方程。暴发疫情流感病毒分离,阳性率为41.86%;2-4月流感流行期暴发疫情与门诊就诊的流感样病例流感病毒阳性率差异不显著（χ^2=0.38,P〉0.05）。结论杭州市流感暴发疫情罹患率与首例与发病高峰值时间间隔、流行时限、首例与疫情报告时间间隔、单位城乡分布、单位等级5个因素有关。     

2008-2019年南宁市手足口病暴发疫情流行特征分析

目的 了解南宁市手足口病暴发疫情的流行病学特征,为手足口病暴发疫情防控工作提供科学依据.方法 收集整理2008-2019年间南宁市报告的手足口病暴发疫情处置资料进行分析.结果 2008-2019年南宁市累计报告手足口病暴发疫情104起,每年3-6月和9-10月是疫情高发期,城区报告疫情起数较多,占61.54％,但县区罹...