Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Influenza Other Respir Viruses. 2018 Jan;12(1):104-112. doi: 10.1111/irv.12489. Epub 2018 Feb 16.
Understanding the burden of influenza-associated severe acute respiratory infection (SARI) is important for setting national influenza surveillance and vaccine priorities. Estimating influenza-associated SARI rates requires hospital-based surveillance data and a population-based denominator, which can be challenging to determine.
We present an application of the World Health Organization's recently developed manual (WHO Manual) including hospital admission survey (HAS) methods for estimating the burden of influenza-associated SARI, with lessons learned to help others calculate similar estimates.
Using an existing SARI surveillance platform in Cambodia, we counted influenza-associated SARI cases during 2015 at one sentinel surveillance site in Svay Rieng Province. We applied WHO Manual-derived methods to count respiratory hospitalizations at all hospitals within the catchment area, where 95% of the sentinel site case-patients resided. We used HAS methods to adjust the district-level population denominator for the sentinel site and calculated the incidence rate of influenza-associated SARI by dividing the number of influenza-positive SARI infections by the adjusted population denominator and multiplying by 100 000. We extrapolated the rate to the provincial population to derive a case count for 2015. We evaluated data sources, detailed steps of implementation, and identified lessons learned.
We estimated an adjusted influenza-associated 2015 SARI rate of 13.5/100 000 persons for the catchment area of Svay Rieng Hospital and 77 influenza-associated SARI cases in Svay Rieng Province after extrapolation.
Methods detailed in the WHO Manual and operationalized successfully in Cambodia can be used in other settings to estimate rates of influenza-associated SARI.
了解流感相关严重急性呼吸道感染（SARI）的负担对于制定国家流感监测和疫苗优先事项至关重要。估计流感相关 SARI 发病率需要基于医院的监测数据和基于人群的分母，这可能难以确定。
我们介绍了世界卫生组织（WHO）最近开发的手册（WHO 手册）中包括医院入院调查（HAS）方法在内的应用，用于估计流感相关 SARI 的负担，并提供了一些经验教训，以帮助其他人计算类似的估计。
我们利用柬埔寨现有的 SARI 监测平台，在斯威里昂省的一个哨点监测点计算了 2015 年流感相关 SARI 病例。我们应用 WHO 手册中方法计算了整个监测区所有医院的呼吸道住院人数，其中 95%的哨点病例患者居住在该监测区。我们使用 HAS 方法对哨点所在地区的人口分母进行调整，并通过将流感阳性 SARI 感染人数除以调整后的人口分母，再乘以 100000 来计算流感相关 SARI 的发病率。我们将该比率外推到省级人口，以得出 2015 年的病例数。我们评估了数据来源、实施的详细步骤，并确定了经验教训。
我们估计，斯威里昂医院监测区调整后的 2015 年流感相关 SARI 发病率为 13.5/100000 人，斯威里昂省有 77 例流感相关 SARI 病例。
在柬埔寨成功实施的 WHO 手册中详细描述的方法可用于其他地区估计流感相关 SARI 的发病率。
