Just two months after being officially declared Ebola-free, Liberia has been struck with more cases of the deadly disease as the virus worryingly resurfaces. That’s not to say that the situation is due to complacency from health officials, but it does once again highlight the desperate need for effective preventive measures.
Although there are currently no licensed vaccines, trials are underway for several encouraging candidates, raising hopes that we could have one by the end of the year. And we may now have another potential agent to add to this promising list, as scientists have just developed an inhalable vaccine that has been shown to provide non-human primates with protection. Not only is this type of vaccine a first for Ebola, but the delivery method could prove extremely useful in remote areas of developing nations.
“A needle-free, inhalable vaccine against Ebola presents certain advantages,” lead author Michelle Meyer from the University of Texas Medical Branch (UTMB) at Galveston said in a statement. “Immunization will not require trained medical personnel.”
The idea for this vaccine was sparked following observations that an individual can become infected if the virus comes into contact with the mucus-lined membranes of the respiratory tract, indicating that these protective barriers to the delicate airways could serve as an entry point for the pathogen. Furthermore, there are numerous lines of evidence to suggest that many potentially threatening agents are infectious when in the form of particles suspended in the air, so-called aerosols, which could be inhaled.
To explore the possibility of using this knowledge to our advantage, scientists from UTMB in collaboration with the National Institutes of Health developed two Ebola virus vaccines, one of which was delivered to the airways as a liquid, the other an inhaled aerosol. This study, published in the Journal of Clinical Investigation, actually marks the first time that such a delivery method has been tested for a viral hemorrhagic fever, the most famous of which are Ebola and Marburg.
For their investigation, they provided non-human primates with one of the forms of the vaccine and documented how the immune system responded, comparing the findings with another group immunized with a different, injectable vaccine. Remarkably, just one dose of the inhaled vaccine prevented the animals from both severe disease and death following exposure to the often fatal virus.
“The study demonstrates successful aerosol vaccination against a viral hemorrhagic fever for the first time,” study author Alex Bukreyev said in a statement. “A single-dose aerosol vaccine would enable both prevention and containment of Ebola infections, in a natural outbreak setting where healthcare infrastructure is lacking or during bioterrorism and biological warfare scenarios.”
Although this candidate is lagging behind others that are already being tested in humans, the researchers are hopeful that the findings will lead to approval for advancement into clinical trials. And with the virus already starting to make a comeback, it seems it is better late than never.
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