Senga Mikiko, Koi Alpha, Moses Lina, Wauquier Nadia, Barboza Philippe, Fernandez-Garcia Maria Dolores, Engedashet Etsub, Kuti-George Fredson, Mitiku Aychiluhim Damtew, Vandi Mohamed, Kargbo David, Formenty Pierre, Hugonnet Stephane, Bertherat Eric, Lane Christopher
Department of Pandemic and Epidemic Diseases, World Health Organization, Geneva, Switzerland
Kenema District Health Management Team, Kenema District, Sierra Leone.
Philos Trans R Soc Lond B Biol Sci. 2017 May 26;372(1721). doi: 10.1098/rstb.2016.0300.
Contact tracing in an Ebola virus disease (EVD) outbreak is the process of identifying individuals who may have been exposed to infected persons with the virus, followed by monitoring for 21 days (the maximum incubation period) from the date of the most recent exposure. The goal is to achieve early detection and isolation of any new cases in order to prevent further transmission. We performed a retrospective data analysis of 261 probable and confirmed EVD cases in the national EVD database and 2525 contacts in the Contact Line Lists in Kenema district, Sierra Leone between 27 April and 4 September 2014 to assess the performance of contact tracing during the initial stage of the outbreak. The completion rate of the 21-day monitoring period was 89% among the 2525 contacts. However, only 44% of the EVD cases had contacts registered in the Contact Line List and 6% of probable or confirmed cases had previously been identified as contacts. Touching the body fluids of the case and having direct physical contact with the body of the case conferred a 9- and 20-fold increased risk of EVD status, respectively. Our findings indicate that incompleteness of contact tracing led to considerable unmonitored transmission in the early months of the epidemic. To improve the performance of early outbreak contact tracing in resource poor settings, our results suggest the need for prioritized contact tracing after careful risk assessment and better alignment of Contact Line Listing with case ascertainment and investigation.This article is part of the themed issue 'The 2013-2016 West African Ebola epidemic: data, decision-making and disease control'.
埃博拉病毒病(EVD)疫情中的接触者追踪是指识别可能接触过该病毒感染者的个体,并从最近一次接触之日起对其进行为期21天(最长潜伏期)的监测。目的是尽早发现并隔离任何新病例,以防止进一步传播。我们对2014年4月27日至9月4日期间塞拉利昂凯内马区国家EVD数据库中的261例疑似和确诊EVD病例以及接触者名单中的2525名接触者进行了回顾性数据分析,以评估疫情初期接触者追踪的成效。在2525名接触者中,21天监测期的完成率为89%。然而,只有44%的EVD病例在接触者名单中登记了接触者,6%的疑似或确诊病例此前曾被确定为接触者。接触病例的体液和与病例身体直接进行身体接触分别使EVD感染风险增加了9倍和20倍。我们的研究结果表明,接触者追踪的不完整导致了疫情最初几个月中大量未被监测到的传播。为了提高资源匮乏地区疫情初期接触者追踪的成效,我们的研究结果表明,需要在仔细进行风险评估后优先进行接触者追踪,并使接触者名单与病例确诊和调查更好地协调一致。本文是主题为“2013 - 2016年西非埃博拉疫情:数据、决策与疾病控制”的特刊的一部分。