A Vaccine for Ebola Virus is Safe in Healthy Adults

A DNA vaccine for Ebola virus was found to be safe in healthy adults, according to a study published in the November issue of journal Clinical and Vaccine Immunology. The vaccine developed by a research team from Vaccine Research Centre at National Institute of Allergy and Infectious Diseases, Bethesda, Maryland and Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, Washington was well-tolerated, with no significant adverse events or coagulation abnormalities.

Since 1976, Ebola virus has been spreading panic in developing countries of Africa like the Democratic Republic of the Congo (formerly Zaire) and Sudan. In recent years, it (especially Ebola-Zaire subtype) has surfaced in Uganda, Gabon and The Republic of Congo. This virus is deadly as it causes death in 50 and 90 per cent of all clinically ill cases.


The vaccine encoding the envelope glycoprotein (GP) from the Zaire and Sudan/Gulu species of Ebola virus as well as nucleoprotein was administered to 21 adults aged between 18 and 44. Each healthy volunteer received three injections of the vaccine. Of them, five received at a dose of 2 mg, 8 at 4 mg and 8 at 8 mg and these vaccinated adults were compared with 6 placebo subjects. The treated group showed specific antibody responses as well as generation of lymphocytes (CD8+ T-cell and CD4+ T-cell), a type of white blood cells, which are capable of killing the whole virus and help generate antibodies in response to GP of Ebola virus.

The lurking threat is the natural reservoir of the Ebola virus, which seems to reside in the rain forests of the African continent and in areas of the Western Pacific. On the African continent, Ebola infections of human cases have been linked to direct contact with gorillas, chimpanzees, monkeys, forest antelope and porcupines found dead in the rainforest. So far, the Ebola virus has been detected in the wild in carcasses of chimpanzees (in Côte-d’Ivoire and Republic of Congo), gorillas (Gabon and Republic of Congo) and duikers (Republic of Congo).

As any time, humans can come into contact with this natural reservoir during their day-to-day activities, most of which revolve around forest and wild life. No specific treatment or vaccine is yet available for Ebola haemorrhagic fever. Several vaccine candidates are being tested but it could be several years before any are available. The present study which highlights the safety of a DNA vaccine for Ebola virus, which has wreaked havoc in recent years, is very important and encouraging for developing countries in Africa as well as Asia.