Influenza Program, US Center for Disease Control and Prevention-India office, New Delhi, India.
Centre for Community Medicine, All India Institute of Medical Sciences, New Delhi, India.
PLoS One. 2018 Apr 26;13(4):e0196495. doi: 10.1371/journal.pone.0196495. eCollection 2018.
To estimate rates of community-level influenza-like-illness (ILI) and influenza-associated ILI in rural north India.
During 2011, we conducted household-based healthcare utilization surveys (HUS) for any acute medical illness (AMI) in preceding 14days among residents of 28villages of Ballabgarh, in north India. Concurrently, we conducted clinic-based surveillance (CBS) in the area for AMI episodes with illness onset ≤3days and collected nasal and throat swabs for influenza virus testing using real-time polymerase chain reaction. Retrospectively, we applied ILI case definition (measured/reported fever and cough) to HUS and CBS data. We attributed 14days of risk-time per person surveyed in HUS and estimated community ILI rate by dividing the number of ILI cases in HUS by total risk-time. We used CBS data on influenza positivity and applied it to HUS-based community ILI rates by age, month, and clinic type, to estimate the community influenza-associated ILI rates.
The HUS of 69,369 residents during the year generated risk-time of 3945 person-years (p-y) and identified 150 (5%, 95%CI: 4-6) ILI episodes (38 ILI episodes/1,000 p-y; 95% CI 32-44). Among 1,372 ILI cases enrolled from clinics, 126 (9%; 95% CI 8-11) had laboratory-confirmed influenza (A (H3N2) = 72; B = 54). After adjusting for age, month, and clinic type, overall influenza-associated ILI rate was 4.8/1,000 p-y; rates were highest among children <5 years (13; 95% CI: 4-29) and persons≥60 years (11; 95%CI: 2-30).
We present a novel way to use HUS and CBS data to generate estimates of community burden of influenza. Although the confidence intervals overlapped considerably, higher point estimates for burden among young children and older adults shows the utility for exploring the value of influenza vaccination among target groups.
估计印度北部农村地区社区流感样疾病（ILI）和与流感相关的 ILI 的发病率。
2011 年，我们在印度北部巴拉伯格尔的 28 个村庄中，对过去 14 天内出现任何急性医疗疾病（AMI）的居民进行了基于家庭的医疗保健利用调查（HUS）。同时，我们在该地区对发病≤3 天的 AMI 病例进行了基于诊所的监测（CBS），并使用实时聚合酶链反应收集鼻和咽拭子进行流感病毒检测。回顾性地，我们将 ILI 病例定义（测量/报告的发热和咳嗽）应用于 HUS 和 CBS 数据。我们将每个接受调查的人 14 天的风险时间除以 HUS 中的总风险时间，以计算 ILI 病例数，从而估计社区 ILI 发病率。我们使用 CBS 数据中的流感阳性率，并将其应用于基于 HUS 的社区 ILI 发病率，按年龄、月份和诊所类型进行分层，以估计社区中与流感相关的 ILI 发病率。
该年对 69369 名居民进行的 HUS 产生了 3945 人年的风险时间（p-y），并确定了 150 例（5%，95%CI：4-6）ILI 病例（38 例 ILI 病例/1000 p-y；95%CI：32-44）。在从诊所招募的 1372 例 ILI 病例中，有 126 例（9%，95%CI：8-11）具有实验室确诊的流感（A（H3N2）=72 例；B=54 例）。在调整年龄、月份和诊所类型后，总体流感相关 ILI 发病率为 4.8/1000 p-y；发病率在<5 岁的儿童中最高（13；95%CI：4-29）和≥60 岁的老年人中最高（11；95%CI：2-30）。
我们提出了一种使用 HUS 和 CBS 数据生成流感社区负担估计的新方法。尽管置信区间重叠较大，但在儿童和老年人中较高的负担点估计值表明，该方法在探索目标人群中流感疫苗接种的价值方面具有一定的效用。
