By Sola Ogundipe
Who says an Ebola vaccine has to be injected? Certainly not.
Researchers at the University of Texas Medical Branch (UTMB), Galveston have discovered an inhalable vaccine that can protect rhesus macaque monkeys against severe illness and death when they were exposed to the Ebola virus.
Rhesus Macaques are among the most widespread primates after humans and are the monkeys most widely used in biomedical research.
Findings published in the Journal of Clinical Investigation suggests that the linings of the airways may be an important point of entry for the Ebola virus into the body.
Alexander Bukreyev, a professor of virology at the University said the study demonstrates successful aerosol vaccination against a viral hemorrhagic fever for the first time.
“A single-dose aerosol vaccine would enable both prevention and containment of Ebola infections, in a natural outbreak setting where health care infrastructure is lacking or during bioterrorism and biological warfare scenarios,” he added.
“A needle-free, inhalable vaccine against Ebola presents certain advantages. Immunization will not require trained medical personnel,” Michelle Meyer, a postdoctoral fellow in the pathology department at the UTMB further stated.
In the new study, Bukreyev and colleagues administered the inhaled vaccine to six rhesus macaque monkeys.
A month later, the team injected the monkeys with a dose of Ebola virus that was 1,000 times the level that would normally be deadly.
None of the monkeys died or developed severe cases Ebola, although a few developed mild depression.
The new vaccine is made from a mild, very common respiratory virus, called human parainfluenza virus type 3 (HPIV3), that has been engineered to include genes from the Ebola virus that encode the proteins of the virus’s outer coat.
The researchers found that the engineered virus infiltrated monkey’s respiratory tracts, and replicated there, triggering the cells to produce many copies of the Ebola virus’s coat.
The immune system, in turn, recognized that outer coat as foreign, and activated a response.
The new vaccine would be an improvement over other vaccines not only because it could be delivered by people other than medical professionals.
Researchers said the vaccine triggered two different forms of immunity — a “local” immune response, in the mucous membranes of the respiratory tract, as well as a body-wide immune system response, in form of immune cells circulating throughout the body.
Most other Ebola vaccines only stimulate systemic immunity, so the new vaccine could add another layer of protection.
The National Institutes of Health is currently starting a Phase I trial of the vaccine, in a small number of people, to see if the drug is safe.
Further studies are needed to confirm that the vaccine is both safe and effective, and may likely take at least three years before the vaccine be used in the field.
The 18-month-old west African Ebola epidemic has sickened more than 27,000 and left more than 15,000 dead, mostly in Guinea, Liberia and Sierra Leone, according to the World Health Organization.
Vaccines and treatments have been used in the field, either in organised clinical trials or in certain special situations.
But many of the vaccines are shots that must be administered by people with at least some medical training.
But in the parts of Africa hard-hit by the outbreak, Ebola has decimated the health workforce especially hard, leading to severe shortages in doctors and nurses.