An inhaled aerosol vaccine against Ebola has been found to effectively neutralize the virus in rhesus macaques, activating immune cells in their respiratory systems and fully protecting the monkeys from the symptoms of hemorrhagic fever.
The study was carried out by researchers at the University of Texas Medical Branch in Galveston and the National Institutes of Health in Bethesda, Maryland, and the results were published in the Journal of Clinical Investigation, the New York Times reported earlier this week. It was their first attempt to use the aerosol to vaccinate monkeys against the deadly virus.
Alexander Bukreyev, a virologist from the University of Texas Medical Branch told the Times that their vaccine was “one of the few… that works” in monkeys, but as the newspaper pointed out, this success will not necessarily translate into results in humans, as already this year, a vaccine which worked in monkeys failed in people.
Dr. Daniel Bausch, a virologist from Tulane University, added that while the results represented “a positive step forward,” he cautioned that it was “not a breakthrough.” Dr. Igor Lukashevich, a medical virologist from the University of Louisville who was not involved with the study, noted, however, that the “aerosolized form of the vaccine” is “what the field needs right now.”
Lungs could be first line of defense against the virus
According to the Times, the aerosol can be administered without assistance from doctors or other medical professionals, which would make it ideal for use in developing nations where there is a shortage of personnel capable of giving most types of vaccines. This includes West Africa, a place reportedly in the midst of the worst Ebola epidemic in history.
Lead author Dr. Michelle Meyer, a postdoctoral fellow at the UT Medical Branch, explained that the aerosol generated significantly more ant-Ebola immunity cells in the respiratory tract than in the blood or spleen, which indicates that the lungs serve as the first layer of protection against the disease. This makes it “ideal to combat the virus at the site of infection,” she said.
In the study, four rhesus macaques were given one dose of the aerosol vaccine, four others were given two doses, two more were given the vaccine in a liquid form, and two served as controls and were not vaccinated at all. Four weeks later, all 12 of the monkeys were injected with a dose of the Ebola virus that was 1,000 times stronger than a lethal dose.
Just over one week later, the new unvaccinated monkeys contracted the hemorrhagic fever and had to be euthanized. The vaccinated monkeys remained healthy, however, and after the end of the study, the surviving monkeys were examined. The researchers found no sign of Ebola virus in their blood or tissue, and dose was enough to protect them.
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