More accurate and rapid diagnostic tests and significantly increased capacity to isolate patients are crucial for responding to any future outbreak of the Ebola virus according to a new paper published today (24 July). A team from King’s Health Partners and Connaught Hospital in Sierra Leone say that up to one in five of all positive Ebola cases during the most recent outbreak may have been missed when using existing case definition procedures for identifying the disease.
In the paper, published in The Lancet Infectious Diseases, the King’s Sierra Leone Partnership team describes how the wide-ranging variety of symptoms early on in the course of the disease made it very difficult to differentiate Ebola from other causes of severe illness. This means that Ebola cases were likely to have been missed wherever these case definitions were in use, and that as a result these patients may have been seen at general health care facilities, putting health care workers and other patients at risk.
The study suggests that 20 cases per 100 Ebola virus disease presentations would not be detected at screening and could be given admission to general clinical areas if an existing case definition, such as the WHO case definition, was used. For example, around one in ten Ebola cases did not present with any fever or history of fever. Optimisation of the case definition based on subsequent experience did not enable the team to adequately improve this case detection rate. The paper concludes that widespread adoption of a rapid point-of-care Ebola diagnostic test is the only way to help with this differential in the future. In a trial earlier this year, the King’s Sierra Leone Partnership team showed that such a test has the potential to accurately and quickly identify 100% of Ebola cases.(1)
Additionally, although the team were able to set up and run a small number of isolation centres for both treating and holding suspected Ebola patients, the limited capacity for isolation elsewhere in Sierra Leone meant that there were times when symptomatic patients had to be sent home until a bed became available. Building capacity would be critical for future outbreaks to allow teams to isolate patients while they more accurately identify all positive cases.
Dr Naomi Walker, King’s Sierra Leone Partnership, says that: “This study shows that, despite our best efforts, the lack of an accurate and rapid means of diagnosis and sufficient capacity to isolate all suspected cases mean that it is likely that some positive cases were misidentified. It is crucial that we learn the lessons from this outbreak to ensure we are better prepared in the future.”
King’s Sierra Leone Partnership has provided a full clinical response to Ebola at Connaught Hospital in the capital Freetown. It is an initiative of King’s Health Partners Academic Health Sciences Centre, an innovative partnership between King’s College London and three of London’s leading NHS foundation trusts – Guy’s and St Thomas’, King’s College Hospital and South London and Maudsley. The study was based on data from over 700 cases of suspected Ebola at Connaught between May 2014 and December 2014, during which time the team saw over half of the confirmed cases in Freetown.
Notes to editors
• The paper ‘Clinical features of patients isolated for suspected Ebola virus disease at Connaught Hospital, Freetown, Sierra Leone: a retrospective cohort study’ is available to read from 00:01 Friday 24 July in The Lancet Infectious Diseases at http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(15)00137-1/abstract. Advance copies are available under strict embargo.
• King’s Sierra Leone Partnership is part of King’s Health Partners Academic Health Sciences Centre (AHSC), a pioneering collaboration between King’s College London, and Guy’s and St Thomas’, King’s College Hospital and South London and Maudsley NHS Foundation Trusts. For more information visit www.kingshealthpartners.org
• The team, originally in Sierra Leone to help build and strengthen the local health system, has played a vital role in responding to Ebola since the virus first reached the country in May 2014. They have worked closely with the Sierra Leone Government and local and international partners to increase the local capacity to identify and treat Ebola patients, provide essential clinical training, spread best practice quickly and, by helping set up an Ebola Command Centre in Freetown, manage the effective flow of patients across the city. To find out more about King’s Sierra Leone Partnership visit http://kslp.org.uk/
• The study for Eurosurveillance, ‘Evaluation of a point-of-care blood test for identification of Ebola virus disease at Ebola holding units, Western Area, Sierra Leone, January to February 2015’ is available at http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=21073
• The team have also published a ‘Guide for the Establishment and Supervision of Ebola Holding Units’.
• For further information please contact Michael Carden, Head of Communications, King’s Health Partners on 0207 188 4058