Tuesday, July 28, 2015

An Inhalable Vaccine Against Ebola?

A recent research study published in the Journal of Clinical Investigation offers hope that a vaccine against the Ebola virus (and perhaps other infectious diseases) can be delivered as an aerosol spray rather than injected. In the study, monkeys were given either an aerosolized vaccine against Ebola via the respiratory tract; the same vaccine in injected liquid form; or no vaccine at all. Four weeks later, all of the monkeys were deliberately exposed to the Ebola virus to see what would happen. The non-vaccinated monkeys died, whereas all of the treated monkeys survived.

At the end of the experiment the vaccinated animals were euthanized and blood and tissue samples were taken for analysis. Antibody titers against the Ebola virus were high in all of the vaccinated animals regardless of route of vaccine delivery, and there were no signs of the Ebola virus. But in addition, the animals that had received the aerosolized vaccine had developed an especially vigorous immune cell response in the lungs. This latter finding is important, because the Ebola virus may infect some of its victims via droplets of aerosolized fluids that enter the lungs. The finding of an enhanced immune cell response in the lungs suggests that an aerosolized vaccine might offer an extra level of protection against Ebola.

But perhaps the biggest advantage of an aerosolized vaccine is that it could be delivered without the assistance of medical personnel. This would be a huge advantage in places such as West Africa (where the recent outbreak of Ebola occurred) because medical personnel are scarce in that region.

An aerosolized vaccine against Ebola has never been tried in humans. Clinical trials in humans will be needed before such a vaccine would become widely available.

No comments: