Ebola Vaccine Alternative

           On our previous post, “McAfee Engineers Working On Ebola Anti-virus?” we explored the process a vaccine goes through in order to be released to the public for treatment. As the post explained, the development of a vaccine can years to complete. So what other options do Ebola patients have? To this date, more than 15,00 people have contracted the virus and more than 5,400 people have died. WHO (World Health Organization) has announced two candidate vaccines are currently in phase 1 trials (clinical trials) and plans are to bring them to the market as early as January 2015. But, what can be done in the meantime? Well, there is another way to treat Ebola patients until a proper vaccine is released to the market. The method is conducted by transfusing blood, plasma or plasma immunoglobulin fractions from convalescent donors who have fully recovered from the virus and have developed protective and long-lasting immunoglobulin. In the article, “Ebola virus convalescent blood products: Where we are now and where we may need to go,” Thierry Burnouf, from the Graduate Institute of Biomedical Materials and Tissue Engineering, explores the possibilities of these alternatives.

1.    The Past

The use of human convalescent blood products first started in the early 20^th century. It was regularly used to treat various infections since vaccines and other ways of antibiotics were not yet developed. Some of the most common viruses treated by using this method have been:

·      Influenza

·      Mumps

·      Poliomyelitis

·      Typhoid fever

·      Herpes zoster

·      Measles

2.    The Present

Today, new accomplishments in science and technology allow a more controlled and safer procedures. Modern blood transfusion is the key factor when preparing convalescent blood products (See Figure 1).   

a.    Whole blood

In this process, a donor needs to be pre-screened before blood can be collected. Then, blood is collected with an anticoagulant solution and need to be transfused within 24 hours to maintain clotting factors. Furthermore, whole blood has to be stored at 2-6°C for up to 35 days.

During a study in 1999, eight Ebola patients were treated with convalescent whole blood; in which seven survived. It should be known that the efficiency of whole blood was not proved completely during this study.

b.    Plasma

Plasma is obtained by decantation or centrifugation, of whole blood or by apheresis. Apheresis is the preferred mode of collection for many reasons: larger volume collected, possibility of more frequent donations, and absence of impact on the hemoglobin level due to the reinfusion of the red blood cells.

3   The Future
In the absence of a vaccine for Ebola, WHO has approved the use of these alternatives mentioned above under certain conditions that mostly require the safety of patients. At this point, whole blood and plasma seem to be a good alternative to treat patients. However, There are some challenges we need to point out. For example, most countries in West-Africa do not have the proper infrastructures and necessary tools to proceed with this method. Additionally, Having controlled clinical evaluations is also important to establish safe treatments for patients. If regulations established by WHO are followed, this method can be safely applied for future virus outbreaks.

References:

Burnouf, T. Seghatchian, J. 2014. Ebola virus convalescent blood products: Where we are now and where we may need to go. Transfusion and Apheresis Science. Retrieved from:

http://www.sciencedirect.com.mutex.gmu.edu/science/article/pii/S1473050214001724#

http://apps.who.int/iris/bitstream/10665/144032/1/roadmapsitrep_19Nov14_eng.pdf?ua=1