Muhimbili University of Health and Allied Sciences, School of Public Health and Social Sciences (SPHSS), Dar es Salaam, Tanzania.
Tanzania Field Epidemiology and Laboratory Training Program (TFELTP), Dar es Salaam, Tanzania.
PLoS One. 2023 Mar 20;18(3):e0283043. doi: 10.1371/journal.pone.0283043. eCollection 2023.
The World Health Organization (WHO) recommends periodic evaluations of influenza surveillance systems to identify areas for improvement and provide evidence of data reliability for policymaking. However, data on the performance of established influenza surveillance systems are limited in Africa, including Tanzania. We aimed to assess the usefulness of the Influenza surveillance system in Tanzania and to ascertain if the system meets its objectives, including; estimating the burden of disease caused by the Influenza virus in Tanzania and identifying any circulating viral strains with pandemic potential.
From March to April 2021, we collected retrospective data through a review of the Tanzania National Influenza Surveillance System electronic forms for 2019. Furthermore, we interviewed the surveillance personnel about the system's description and operating procedures. Case definition (ILI-Influenza Like Illness and SARI-Severe Acute Respiratory Illness), results, and demographic characteristics of each patient were obtained from the Laboratory Information System (Disa*Lab) at Tanzania National Influenza Center. The United States Centers for disease control and prevention updated guidelines for evaluating public health surveillance systems were used to evaluate the system's attributes. Additionally, the system's performance indicators (including turnaround time) were obtained by evaluating Surveillance system attributes, each being scored on a scale of 1 to 5 (very poor to excellent performance).
A total of 1731 nasopharyngeal and oropharyngeal samples were collected from each suspected influenza case in 2019 from fourteen (14/14) sentinel sites of the influenza surveillance system in Tanzania. Laboratory-confirmed cases were 21.5% (373/1731) with a predictive value positive of 21.7%. The majority of patients (76.1%) tested positive for Influenza A. Thirty-seven percent of patients' results met the required turnaround time, and 40% of case-based forms were incompletely filled. Although the accuracy of the data was good (100%), the consistency of the data was below (77%) the established target of ≥ 95%.
The overall system performance was satisfactory in conforming with its objectives and generating accurate data, with an average performance of 100%. The system's complexity contributed to the reduced consistency of data from sentinel sites to the National Public Health Laboratory of Tanzania. Improvement in the use of the available data could be made to inform and promote preventive measures, especially among the most vulnerable population. Increasing sentinel sites would increase population coverage and the level of system representativeness.
世界卫生组织（WHO）建议定期评估流感监测系统，以确定改进领域，并为决策提供数据可靠性证据。然而，在非洲，包括坦桑尼亚在内，有关既定流感监测系统性能的数据有限。我们旨在评估坦桑尼亚流感监测系统的有用性，并确定该系统是否符合其目标，包括：估计流感病毒在坦桑尼亚造成的疾病负担，并确定任何具有大流行潜力的循环病毒株。
2021 年 3 月至 4 月，我们通过审查坦桑尼亚国家流感监测系统 2019 年的电子表格，收集了回顾性数据。此外，我们还采访了监测人员，了解系统的描述和操作程序。从坦桑尼亚国家流感中心的实验室信息系统（Disa*Lab）获得了每个病例的定义（ILI-流感样疾病和 SARI-严重急性呼吸道疾病）、结果和人口统计学特征。美国疾病控制与预防中心更新了评估公共卫生监测系统的指南，用于评估系统的属性。此外，还通过评估监测系统属性获得了系统的性能指标（包括周转时间），每个属性的评分范围为 1 到 5（非常差到优秀）。
2019 年，从坦桑尼亚流感监测系统的 14 个哨点（14/14）的每个疑似流感病例中收集了 1731 份鼻咽和口咽样本。实验室确诊病例为 21.5%（373/1731），阳性预测值为 21.7%。大多数患者（76.1%）检测出甲型流感呈阳性。37%的患者结果符合规定的周转时间要求，40%的病例报告表填写不完整。尽管数据的准确性良好（100%），但数据的一致性低于（77%）既定目标的≥95%。
总体而言，该系统在符合其目标和生成准确数据方面表现令人满意，平均性能为 100%。系统的复杂性导致来自哨点的数据一致性降低，无法到达坦桑尼亚国家公共卫生实验室。可以改进对现有数据的利用，为弱势群体提供信息并促进预防措施。增加哨点将增加人口覆盖范围和系统代表性水平。
