Credit: Elise Amendola
Experts from the World Health Organization (WHO) have identified several interventions that should be the focus of clinical evaluation for treating and preventing Ebola.
Transfusions of blood products from Ebola survivors topped this list.
Of course, such blood preparations, like the other interventions the WHO discussed, have not been approved to treat or prevent Ebola.
However, they could be available before the year is out, according to WHO estimates. The organization is exploring options to conduct clinical trials of blood products in Ebola patients.
Previous studies have suggested blood transfusions from Ebola survivors might prevent or treat Ebola virus infection. However, it is unclear whether antibodies in the plasma of survivors are sufficient to treat or prevent the disease.
Safety is also a concern, although the WHO said transfusions should be safe if they are provided by well-managed blood banks. Still, there is a risk of transmitting blood-borne pathogens and a theoretical concern about antibody-dependent enhancement of Ebola virus infection.
“[T]here was a lot of discussion and emphasis on blood, on blood transfusion, whole-blood transfusion, as well as on plasma that can be purified from convalescent serum,” said Marie-Paule Kieny, Assistant Director-General at the WHO.
“There was consensus that this has a good chance to work and that, also, this is something that can be produced now from the affected countries themselves.”
The experts also agreed that the international community needs to help affected countries create the necessary infrastructure to draw blood safely and prepare the blood products safely.
Aside from blood transfusions, the WHO experts mentioned 2 potential Ebola vaccines that should be a priority. Safety studies of these vaccines—based on vesicular stomatitis virus (VSV-EBO) and chimpanzee adenovirus (ChAd-EBO)—are beginning in the US and are slated to begin in Africa and Europe in mid-September.
If proven safe, a vaccine could be available in November 2014 for priority use in healthcare workers.
The WHO experts also discussed the availability and evidence supporting the use of novel therapeutic drugs, including monoclonal antibodies, RNA-based drugs, and small antiviral molecules. They considered the potential use of existing drugs approved for other diseases and conditions as well.
Of the novel products discussed, some have shown great promise in monkey models. Others have been used in a few Ebola patients and appear safe, but the numbers are too small to permit any definitive conclusions about efficacy.
Existing supplies of all experimental medicines are limited, the WHO said. While many efforts are underway to accelerate production, supplies will not be sufficient for several months to come. The prospects of having augmented supplies of vaccines rapidly look slightly better.
The WHO also cautioned that the investigation of the aforementioned interventions should not detract attention from measures to prevent Ebola from spreading.
