Researchers present inner workings of Ebola vaccine trial

February 12, 2016
The Ebola virus, isolated in November 2014 from patient blood samples obtained in Mali. The virus was isolated on Vero cells in a BSL-4 suite at Rocky Mountain Laboratories. Credit: NIAID

An experimental vaccine combined with an innovative way of vaccinating people has resulted in an estimated 100 percent efficacy of the vaccine against the Ebola virus in West Africa—and the approach could establish a new way of responding to outbreaks of emerging pathogens, including the Zika virus.

This is according to two researchers who will discuss their experimental Ebola vaccine trial during the American Association for the Advancement of Science's annual meeting today (Friday, Feb. 12, 2016).

Their discussion will focus on interim results of a study published in The Lancet in July. The study examined an experimental Ebola vaccine as well as a way of deploying the vaccine. The strategy includes vaccinating people who had contact with people who contracted Ebola and also the close contacts of people who had that contact—an approach known as ring vaccination.

Ring vaccination was first used in the 1970s to eradicate smallpox. University of Florida researcher Ira Longini, Ph.D., one of the study's authors, and lead author Ana Maria Henao Restrepo, M.D., a medical officer for the World Health Organization, expect the vaccination strategy could be used to combat other emerging pathogens. It works off the concept of surveillance and containment, and can be designed for interventions other than vaccination, including disease prevention and treatment.

"This type of analysis is a very robust design. It worked for the Ebola vaccine, and could work for the Zika vaccine, or any other emerging threat we might see," Longini said. "Now, we want to make the point that we can almost certainly contain future Ebola outbreaks, and that we will probably have a new paradigm and tool for dealing with new outbreaks of whatever emerges in the future."

Longini, a biostatistics professor in the UF colleges of Public Health and Health Professions and Medicine and director of the UF Center for Statistics and Quantitative Infectious Diseases, will highlight the study's unique design and results of the trial. Because researchers were working in an emergency situation, conducting a standard randomized controlled trial—a trial in which study participants are randomly divided into two groups, one who receives the drug being tested and one who receives a placebo—could have been unethical.

"When you're studying a vaccine for Food and Drug Administration licensure, you would normally like to run the vaccine through a double-blind, randomized placebo-controlled trial," said Longini, also a member of the UF Emerging Pathogens Institute. "To use a placebo in a situation like this Ebola epidemic, in which the probability of someone falling ill and dying is high, could be unethical."

For the researchers' interim results, the study included 7,651 people, more than 3,500 of whom were vaccinated. Researchers found the 100 percent effective in preventing Ebola illness in vaccinated people and 75 percent effective in reducing the risk of Ebola illness in rings where about half of the people had been vaccinated.

The researchers plan to publish their final paper examining the trial soon, but the trial is still ongoing to deliver ring vaccination for any new clusters of Ebola, including a current cluster in Sierra Leone. The researchers also plan to study how long a vaccinated person's immunity to Ebola lasts.

Explore further: Ebola vaccine trial begins in Sierra Leone

Related Stories

Ebola vaccine trial begins in Sierra Leone

April 14, 2015

Thousands of healthcare workers in areas of Sierra Leone that are grappling with Ebola will now begin receiving an experimental vaccine against the often deadly virus, officials said Tuesday.

Effective Ebola vaccine may be here: health officials

August 1, 2015

(HealthDay)—An experimental Ebola vaccine appears highly effective against the deadly infectious disease, according to an interim analysis of findings from a clinical trial being conducted in the West African nation of ...

Recommended for you

Bile acid uptake inhibitor prevents NASH / fatty liver in mice

September 21, 2016

Drugs that interfere with bile acid recycling can prevent several aspects of NASH (nonalcoholic steatohepatitis) in mice fed a high-fat diet, scientists from Emory University School of Medicine and Children's Healthcare of ...

New therapeutic target for Crohn's disease

September 20, 2016

Research from the Sanford Burnham Prebys Medical Discovery Institute (SBP) identifies a promising new target for future drugs to treat inflammatory bowel disease (IBD). The study, published today in Cell Reports, also indicates ...

Mosquitoes, Zika and biotech regulation

September 19, 2016

In a new Policy Forum article in Science, NC State professor Jennifer Kuzma argues that federal authorities are missing an opportunity to revise outdated regulatory processes not fit for modern innovations in biotechnology, ...

Arthritis drug may help with type of hair loss

September 22, 2016

(HealthDay)—For people who suffer from a condition that causes disfiguring hair loss, a drug used for rheumatoid arthritis might regrow their hair, a new, small study suggests.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.