Wednesday, October 08, 2014

ECDC: Risk Of Ebola Transmission From Blood Products & Other Substances Of Human Origin In the EU

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While the Ebola epidemic is currently only spreading in three West African countries, there are concerns that over time the virus could migrate to other African nations - or to other regions of the world - necessitating the thinking about possible public health risks both as they stand now, and how they might evolve down the road.


Yesterday the ECDC published a technical report on managing the potential risks to the blood supply, and to organ and cell donations, due to the Ebola epidemic.

 

Risk of transmission of Ebola virus via donated blood and other substances of human origin in the EU

06 Oct 2014

Abstract

​The epidemic of Ebola virus disease (Zaïre ebolavirus) has increased the risk of Ebola virus transmission via donated blood and blood components, cells, tissues and organs.  

This technical report assesses the risk of Ebola virus transmission through substances of human origin and offers guidelines on the safety of donations where the potential donors are travellers returning from Ebola-affected countries, people exposed to Ebola virus or patients who have recovered from the disease. 

 


SoHO refers to substances of Human Origin, such as blood, blood products, or organ donation. A few excerpts from the Technical report include:

 

Risk of transmission of Ebola virus via donated blood and other substances of human origin in the EU

(Excerpts)

Background


The epidemic of Ebola virus disease (EVD) in West Africa in 2014 has increased the risk of Ebola virus transmission via donated blood and blood components, cells, tissues and organs (substances of human origin - SoHO). There are no specific EU regulations or recommendations for the safety of SoHO donated by patients who have recovered from EVD; people exposed to Ebola virus; or people who have visited or reside in EVD-affected areas.


Ebola virus transmissions through donated blood, tissues or organs have not been described. Asymptomatic replicative infections with Ebola virus have been described [1,2]. Travellers from Ebola-affected countries* are deferred for donation because malaria-risk countries overlap with the current Ebola-risk countries in Africa [3]. However, there is a need for specific guidelines to maintain the safety of SoHO donation by people who have been exposed to Ebola virus. There is a possibility that the current outbreaks in West Africa and the Democratic Republic of Congo will spread to areas where there is no malaria risk.

Risk assessment


The risk of Ebola virus transmission through SoHO is related to the presence of Ebola virus in the donor’s blood, tissues and organs. The presence and concentration of virus in organs, tissues, blood and other bodily fluids changes during the course of the infection. The virus concentration peaks when the patient is most sick, and viruses can be detected and isolated from breast milk and semen weeks after recovery [4]. There are limited data available on when patients become viraemic and infectious during the incubation period. The assumption is that the rate of virus replication and excretion into bodily fluids is not high enough in the pre-symptomatic phase to result in person-to-person transmission through day-to-day contacts in the community. However, there are no data on when viraemia starts during the incubation period. During the symptomatic phase of EVD, the virus is present in high concentrations in all bodily fluids, tissues and organs [5]. When the disease is fatal, the dead body remains highly contagious. After recovery from the acute phase, a patient may continue to excrete live and infective viruses for long periods [4].

There are currently insufficient data on which to base deferral period recommendations for recovered EVD patients; contacts of EVD cases and people who have visited the EVD-affected countries but do not have a documented exposure. EVD has an acute onset of prominent symptoms that is believed to be temporally related to the viraemia. This makes it unlikely that patients in the viraemic phase would be accepted for donation of SoHO, because it would be obvious that they were ill.

Recommendations for the safety of SoHO donations


Travellers or residents returning from EVD-affected areas


It is expected that a deferral of donation for two incubation periods will provide a reasonable margin of safety for asymptomatic donors returning from EVD-affected areas. The longest incubation period for EVD has been estimated at 21 days. However, a recent study has proposed to extend the longest possible incubation period to 25 days [6]. Thus, asymptomatic travellers or residents returning from EVD-affected areas should be temporarily deferred from donation of SoHO for two months after leaving an area affected by EVD.


It should be noted that all Ebola outbreaks to date have occurred in malaria-endemic areas in Africa and that, according to EU Directive 2004/33/EC of 22 March 2004 [3], asymptomatic blood donors returning from malaria risk areas are deferred for blood donation for at least four months. However, the donor deferral for malarial risk is not required when the donation is used exclusively for plasma for fractionation. So, the asymptomatic travellers or residents returning from EVD affected area should defer donation of plasma for fractionation until two months after return.


According to EU directives, malaria testing of potential donors of tissues and cells returning from malaria-endemic areas is mandatory only under certain circumstances, but for organ donation malaria testing is not mandatory [7,8]. Therefore, asymptomatic travellers or residents returning from an Ebola affected area should be deferred from donation of cells, tissues and organs for two months after return. This period can be reduced to one month in the case of urgent need for organ transplantation, provided that the potential donor tests negative for Ebola virus by nucleic acid amplification testing (NAT).


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