October 1, 2023

Ebola vaccine will do little for current crisis

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Ebola GettyFrom Daily Beast

The National Institute of Health announced today that human trials of the Ebola vaccine will begin next week. But it won’t be ready in time for the West Africa’s crisis.

The National Institute of Allergy and Infectious Diseases (NIAID), the branch of the NIH that oversees investigations into infections ranging from Ebola to AIDS to Lyme, announced today that the first of a series of vaccine trials aimed at preventing acquisition of Ebola will be launched next week.

The first trial will be conducted in 20 healthy, uninfected volunteers at the NIH in Bethesda, Maryland. They will be enrolled into the trial three people at a time with frequent monitoring of the vaccine safety. Later this year, a related vaccine will be studied, again in a small number of healthy uninfected volunteers, in Great Britain and in the African countries of Mali and Gambia, which are unaffected by Ebola but which have strong healthcare infrastructures. Very preliminary talks also have commenced to conduct a trial in Nigeria, which has seen more than a dozen Ebola cases during the current outbreak.

The news is surely encouraging, coming as it does on the heels of the news from WHO, which now is preparing for an epidemic of up to 20,000 people, including the 3,000-plus infected thus far, with 1,552 deaths.

Yet NIAID director Dr. Anthony Fauci was very careful to state that for the current outbreak in West Africa, the best approach will not be the vaccine or any new treatments, but rather the approach being used today and last week and last month and last year: early diagnosis, prompt isolation, and use of “personal protective equipment” including gowns, gloves, and masks.

In other words, the vaccine being studied almost certainly will have no impact on the current West Africa crisis. Given the pace of useable science, even with the compressed, hurry-up-already system the candidate vaccine is being ushered through, preliminary results on safety and the vaccine’s ability to provoke a meaningful immune response will not be available until the end of the calendar year—at a point when the now 6-month long epidemic likely will have finally fizzled out.

The science behind the vaccine is extremely interesting and exploits all the latest in vaccinology. A critical gene from the Ebola virus is clipped out, rendering the Ebola virus no longer capable of replication; the Ebola gene is then placed into a different living virus—in this case a chimpanzee virus called adenovirus type 3. The chimp adenovirus is used for a couple of reasons. First, the human recipients of the vaccine will not have pre-existing immunity to it. Ironically, a problem in the world of what is called “vector vaccines” like the chimp-adeno-Ebola vaccine occurs when the recipient already has immunity to the vector virus—adenovirus in this circumstance. If immunity already exists, the recipient will destroy the vaccine product before the vaccine product can trick the exact same immune system into generating fresh immunity to the spliced gene—in this circumstance, the Ebola gene. Use of a non-human vector hopefully circumvents this.

In addition, it is hoped that non-human adenovirus will be safer than adenovirus. Almost two decades ago, at the dawn of viral vector and gene therapy, a young man with a congenital disease died from overwhelming inflammation provoked by adenovirus infusion and infection. The adenovirus he received was simply a vector, bringing a missing gene to his cell. His death cast a pall over the field that remains today; it also makes each investigator and volunteer particularly keen to assure study safety.

The vaccine being studied will contain two genes, one each from two distinct strains of Ebola: the “Zaire” strain that is causing the current epidemic, and the “Sudan” strain. Other trials, to begin in the fall, will study a monovalent vaccine that has a gene only from the Zaire strain.

This work builds on years of previous Ebola vaccine trials conducted by the NIH. None of the specific products have moved forward, but each has revealed new information regarding how best to build a safe and effective vaccine.

Stacked against the ongoing human tragedy playing out in West Africa, the methodical pace of science can seem callous if not intentionally cruel. Yet this is the way of all investigation, an untidy world of trial and error, accident and earned insight, high drama and limited yield. Though all are clamoring for a futuristic solution to Ebola, control in 2014 will depend, as Dr. Fauci made clear, on reliable execution of the most basic and unglamorous approaches to outbreak management: people carefully and caringly treating those with the disease.

For more on this story go to: http://www.thedailybeast.com/articles/2014/08/28/ebola-vaccine-will-do-little-for-current-crisis.html


Related story:

Single animal to human transmission event responsible for 2014 Ebola outbreak

Ebola animal - humanFrom Wn.com

A man that was hired by the community sprays chemicals to try and prevent the spread of the Ebola virus, as local children look on, in Monrovia, Liberia, Friday, Aug. 29, 2014.

NIH-funded scientist uses latest genomic technology to make discovery

Scientists used advanced genomic sequencing technology to identify a single point of infection from an animal reservoir to a human in the current Ebola outbreak in West Africa. This research has also revealed the dynamics of how the Ebola virus has been transmitted from human to human, and traces how the genetic code of the virus is changing over time to adapt to human hosts. Pardis Sabeti, M.D., Ph.D, a 2009 National Institutes of Health Director’s New Innovator awardee and her team carried out the research.

“Dr. Sabeti’s research shows the power of using genomic analysis to track emerging viral outbreaks,” said NIH Director Francis S. Collins, M.D., Ph.D. “This ability produces valuable information that can help inform public health decisions and actions.”

The 2014 Ebola outbreak is now the largest outbreak in history, with current estimates of 2,473 infections and 1350 deaths since it began in late December 2013 according to the World Health Organization. This outbreak is also the first in West Africa and the first to affect urban areas. There are no approved drugs for Ebola virus disease, though prompt diagnosis and aggressive supportive care can improve survival. The disease is characterized by high fever, headache, body aches, intense weakness, stomach pain, and lack of appetite. This is followed by vomiting, diarrhea, rash, impaired kidney and liver function and in some cases, internal and external bleeding.

To better understand why this outbreak is larger than previous outbreaks, Dr. Sabeti, senior associate member of the Broad Institute, Cambridge, Massachusetts, led an extensive analysis of the genetic makeup of Ebola samples from patients living in affected regions. Joined by an international team of scientists, Dr. Sabeti used advanced technology to analyze the genetics of the Ebola samples extremely rapidly and with high levels of accuracy. Using this technology, the researchers pinpointed a single late 2013 introduction from an unspecified animal reservoir into humans. Their study showed that the strain responsible for the West African outbreak separated from a closely related strain found in Central Africa as early as 2004, indicating movement from Central to West Africa over the span of a decade. Studying RNA changes occurring over the span of the outbreak suggests that the first human infection of the outbreak was followed by exclusive human to human transmissions.

While analyzing the genetic makeup of the Ebola samples, Dr. Sabeti and colleagues discovered a number of mutations that arose as the outbreak spread. Some of these mutations, termed nonsynonymous mutations, alter the biological state of the virus and may allow it to continually and rapidly adapt to human immune defenses as the outbreak continues. This feature points to the need for improved methods that will allow for close monitoring of changes in the viral genome and the impact on vaccine targets. Such monitoring, called genomic surveillance, can provide important insights into the biology of how the Ebola virus spreads and evolves. It may also allow scientists to develop improved methods to detect infection, and point the way to new and improved drug and vaccines.

Dr. Sabeti’s New Innovator Award is designed to support exceptionally creative new investigators conducting innovative and high-impact research, as part of the NIH Common Fund’s High-Risk, High-Reward program. The original focus of her research was on Lassa fever, a related but distinct hemorrhagic disease. When the Ebola outbreak began, she shifted her research focus to address this pressing challenge.

“Dr. Sabeti’s New Innovator Award provided flexibility to quickly adjust her research when the 2014 Ebola outbreak began,” said James M. Anderson M.D., Ph.D. director of the Division of Program Coordination, Planning and Strategic Initiatives at NIH. “This exemplifies how the High-Risk, High- Reward program allows researchers to tackle the most challenging and urgent scientific questions.”

The NIH Common Fund supports a series of exceptionally high impact research programs that are broadly relevant to health and disease. Common Fund programs are designed to overcome major research barriers and pursue emerging opportunities for the benefit of the biomedical research community at large. The research products of the Common Fund programs are expected to catalyze disease-specific research supported by the NIH Institutes and Centers. To learn more about the NIH Common Fund, visit http://commonfund.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov

IMAGE: photo: AP / Abbas Dulleh

For more on this story go to: http://article.wn.com/view/2014/08/29/Single_animal_to_human_transmission_event_responsible_for_20_0/


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