Lasting protection against Ebola from single-dose inhaled vaccine looks feasible

Date: Nov-04-2014 An experimental anti-Ebola vaccine that can be taken in inhaled form is

showing promise following animal trials that compared it to injected forms.

A vaccine would not only reduce Ebola transmission from person to person in an ongoing epidemic, but it would also help control further outbreaks.

In trials with non-human primates, a single inhaled dose of the experimental

vaccine, successfully gave the animals long-term protection against lethal Ebola

infection.

Results of the pre-clinical study are reported in the journal Molecular

Pharmaceutics. It is thought to be the only proof to date that a single, non-injected dose of anti-Ebola vaccine can give long-lasting protection.

Co-author Maria A. Croyle, a professor in the College of Pharmacy at the University

of Texas at Austin, is to present the study findings on 5th November at the 2014

American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and

Exposition.

She and her group worked with a team at the National Microbiology Laboratory in

Winnipeg led by co-author Dr. Gary Kobinger.

Inhalable vaccine could overcome many of the obstacles faced by immunization

campaigns

Should it work in humans, the breathable vaccine they are working on could make a

significant contribution to controlling future outbreaks of the deadly virus.

The ease with which vaccines can be shipped, stored and administered plays an

important part in successful immunization campaigns, especially where health systems

and infrastructures are patchy. An inhalable vaccine can overcome many of these

obstacles.

Depending on the strain, the Ebola virus kills between 25% and 90% of the people it

infects and causes devastating outbreaks in Africa and Asia. While scientists are

making great progress toward understanding the biology of the virus, as yet, there are

no licensed treatments or vaccines.

The current epidemic of Ebola in West Africa - where around 70% of cases are fatal

- is the largest and most complex the world has ever seen since the virus was

discovered in 1976. The World Health Organization (WHO) have declared it a public

health emergency of international concern.

A vaccine would not only reduce transmission from person to person in an ongoing

epidemic, but it would also help control further outbreaks.

The inhalable Ebola vaccine improved survival in non-human primates

Prof. Croyle and colleagues have been developing an inhalable form of an Ebola

vaccine for over 7 years. They carried out trials of it in non-human primates and

found it improved survival of immunized animals from 67% to 100% when the animals were infected with 1,000 plaque-forming units of Ebola 150 days after immunization. The strain used was the Zaire strain - the one currently circulating in West Africa.

The authors note: "The formulated vaccine was fully protective against challenge 21

weeks after immunization."

When the animals were given the vaccine by the standard method of intramuscular

injection, only 50% survived the infection challenge.

Prof. Croyle says the main advantage of their vaccine over others currently

undergoing clinical testing is that it offers long-lasting protection after a single

inhaled dose, and explains:

"This is important since the longevity of other vaccines for Ebola that are

currently being evaluated is not fully evaluated. Moreover, this immunization method

is more attractive than an injectable vaccine given the costs associated with syringe

distribution and needle safety and disposal."

She and her team are now planning phase 1 clinical trials in humans. They are also

continuing to analyze data they collected from non-human primate trials that

tested the vaccine given as a thin film under the tongue.

A grant from the National Institutes of Health helped fund the study.

Medical News Today recently learned of another study that suggests surviving or dying from Ebola may be partly down to

genes. The researchers hope that the strains of lab mice they bred for the study

will help speed up the development of anti-Ebola treatments and vaccines.

Written by Catharine Paddock PhD

Not to be reproduced without permission.

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Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.