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Rapid risk assessment: Outbreak of Ebola haemorrhagic fever in Guinea

24 Mar 2014
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Abstract

Main conclusions

Since December 2013, and as of 12 October 2014, 8 997 cases of EVD, including 4 493 deaths, have been reported by the World Health Organization (WHO) in seven reporting countries (Guinea, Liberia, Nigeria, Senegal, Sierra Leone, Spain and the USA). One additional case was reported by the USA on 14 October in a second healthcare worker in Dallas, Texas, who tested positive for Ebola virus after having cared for the first case in the USA.

On 6 October, the Spanish authorities reported a confirmed case of Ebola virus disease (EVD) in a healthcare worker who cared for a patient with Ebola infection repatriated to Spain. The ongoing investigation in Spain is providing information to further understand how the infection was transmitted to this healthcare worker. There is currently no evidence indicating that the healthcare-associated transmission resulted from a change in the transmissibility of the virus. The current recommended infection control measures remain appropriate, if strictly applied. While additional cases among the contacts of the infected nurse cannot be excluded at this time, it is considered extremely unlikely that the event will result in significant spread in Spain.

The evolving epidemic of EVD over the last weeks increases the likelihood that EU residents and travellers to the EVD-affected countries will be exposed to infected or ill persons. The risk of infection for residents and visitors in the affected countries through exposure in the community is considered low if they adhere to the recommended precautions. Residents and visitors to the affected areas run a risk of exposure to EVD in healthcare facilities. The level of this risk is related to how well the infection control measures are being implemented in these settings and the nature of the care required.

As the epidemic is still evolving and more staff is deployed in the affected countries to support the epidemic control, the risk of importation of EVD cases to the EU is increasing. The risk of Ebola virus spreading from an EVD patient who arrives in the EU as result of a planned medical evacuation is considered to be low when appropriate measures are strictly adhered to, but cannot be excluded in exceptional circumstances. The transmission to a healthcare worker in Spain illustrates the connection between the epidemic in West Africa and the risk for the EU, and further stresses the need to control the epidemic in West Africa.

If a symptomatic case of EVD presents in a EU Member State, secondary transmission to caregivers in the family and in healthcare facilities cannot be excluded. This may happen in particular at an early stage of the disease, when patients are not yet very contagious but unprotected contacts are occurring, and at a late stage of the disease, after EVD is confirmed, when patients may experience very high viral loads while undergoing contamination-prone invasive procedure in intensive care units.

Options for risk reduction

• To reduce the risk of infection in West Africa the following options are available: avoid non-essential travel to the affected areas and strictly follow the EVD prevention measures in communities. As there is an increased risk of infection in healthcare facilities, visitors to the EVD-affected countries should identify appropriate incountry healthcare resources prior to travelling.

• To reduce the risk of importation to the EU, the WHO recommendations related to the declaration of a Public Health Event of International Concern (PHEIC) should be applied, in particular effective exit screening. Screening cannot detect infected cases still incubating and not yet presenting with symptoms.

• Based on the evidence of the validity of methods currently available for entry screening at major points of entry, and the likely prevalence of screening-detectable cases among those who have undergone exit screening, the added value of entry screening, if exit screening is being conducted effectively, is likely to be very small, and the resource implications considerable. In the absence of an evaluation of the performance of exit screening, entry screening remains an option to be considered.

• To reduce the risk of transmission within the EU following importation of Ebola virus, the following options are available: epidemic control based on interruption of transmission by infection control measures and implementation of isolation and treatment of patients, and monitoring and contact tracing of contacts; raising awareness and sensitising healthcare providers in the EU about EVD, and supporting them with resources that will help them identify and manage potential EVD patients; enhancing information and communication to travellers departing from EVD-affected countries.

• Transmission to healthcare workers can be prevented by the strict application of infection control measures as recommended by WHO. However, even when infection control measures are thoroughly applied, transmission to healthcare workers can still exceptionally occur. Infection of a healthcare worker may result from a breach in the strict application of the infection control measures, when caring for an infectious patient, when involved in waste management or when removing personal protective equipment (PPE).

Tools that need to be considered for the optimisation of the safe management of patients include regularly repeated hands-on training in the use of PPE, the performance of simulation exercises, continuous supervision and monitoring of both the care of the patient and the putting on and removal of PPE and working in pairs (buddy system). Transfer of the patient to a specialised high level isolation unit is an option that may be considered, taking into account availability, feasibility and the safety of transfer. 

 

Source and date of request

Internal decision, 16 October 2014.
 

Rationale for Risk Assessment

To update the assessment of the risk of importation and transmission of Ebola virus in the EU associated with the epidemic of Ebola virus disease in West Africa currently affecting Guinea, Liberia, Sierra Leone, Spain and the United States of America. We add evidence on the risks of transmission and on hospital infection control, since three healthcare workers having cared for EVD patients outside of West Africa have become infected.
 
This assessment does not cover the ongoing EVD epidemic in the Democratic Republic of Congo or the outbreak of Marburg virus disease in Uganda.
 
The current EVD outbreak was first assessed in an ECDC rapid risk assessment entitled ‘Outbreak of Ebola haemorrhagic fever in Guinea’, dated 23 March 2014. Detailed information about the Ebola virus and the epidemiology of EVD can be found in a series of ECDC publications that are available on the ECDC website.
 

Consulted experts

ECDC contributors (in alphabetical order): Mike Catchpole, Denis Coulombier, Josep Jansa, Kaja Kaasik Aaslav, Teija Korhonen, Diamantis Plachouras, Emmanuel Robesyn, Gianfranco Spiteri, Bertrand Sudre, Marco Testa, Wim Van Bortel and Hervé Zeller.

 

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