Saturday April 20, 2019

Ebola vaccine found effective against new strain

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www.firstpost.com
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New York: A single dose of an experimental Ebola virus (EBOV) vaccine completely protects monkeys against the newly emerged West African Ebola strain when given at least seven days before exposure, and partially protects them if given three days prior, says a new study.

The experimental vaccine is currently undergoing testing in a global clinical trial in humans.

The current Ebola outbreak has killed over 11,000 people mainly in Liberia, Sierra Leone and Guinea.

The positive results of this study further reveal the mechanisms by which an effective immune response is mounted against the Ebola virus, aspects of which have been unclear.

The live-attenuated vaccine, VSV-EBOV, uses genetically engineered vesicular stomatitis virus (VSV) to carry an EBOV gene that has safely induced protective immunity in macaques, the study noted.

In the study by Andrea Marzi from US National Institutes of Health (NIH) VSV-EBOV was administered to groups of macaques 28, 21, 14, seven, or three days before infection with the current outbreak strain EBOV-Makona.

No adverse effects were detectable after immunisation with the lethal dose, and the animals were then monitored for 42 days.

The control group, which was administered a vaccine known not to be effective, showed severe symptoms of Ebola and did not survive.

One animal in the day-three VSV-EBOV vaccination group also did not survive, while the other two animals in this group presented mild and moderate symptoms of Ebola but eventually cleared the virus.

All nine remaining animals in the day 28, 21, 14, and seven vaccination groups did not develop any clinical signs of disease.

(IANS)

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New Antibody Approach to Tackle Ebola, Research To Make Successful Treatments For The Deadly Viral Infection

Antibodies intended for treatment are normally collected from the blood of people who have survived infection. But they can also be tricky to obtain and carry heightened risks such as potential persistent viruses or other pathogens.

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A Congolese health worker administers Ebola vaccine to a boy who had contact with an Ebola sufferer in the village of Mangina, in North Kivu province of the Democratic Republic of Congo, Aug. 18, 2018. VOA

Scientists working on developing vaccines against Ebola have found they can “harvest” antibodies from volunteers vaccinated in research trials and use them to make treatments for the deadly viral infection.

In a study published Tuesday in the journal Cell Reports, the scientists said the approach could be used for Ebola and other newly emerging deadly diseases caused by viruses.

The technique, based on people exposed to the Ebola vaccine but not the Ebola virus itself, suggests protective therapies could be developed from people who are disease-free.

“It is a small, extra step that could lead to new antibody therapies from an increased pool of donors and with reduced risk,” said Alain Townsend, a professor at the MRC Human Immunology Unit at Britain’s Oxford University.

FILE - Health workers treat an unconfirmed Ebola patient inside an Ebola Treatment Center (ETC) in Butembo, Democratic Republic of the Congo, Nov. 3, 2018.
Health workers treat an unconfirmed Ebola patient inside an Ebola Treatment Center (ETC) in Butembo, Democratic Republic of the Congo, Nov. 3, 2018.

He noted that besides Ebola, many experimental vaccines for other life-threatening infections, such as H5N1 and H7N9 bird flu and Middle East Respiratory Syndrome (MERS), are entering clinical trials and could offer similar opportunities for antibodies to be collected.

Ebola is now spreading in Democratic Republic of Congo, where World Health Organization data show at least 676 people have been killed and more than 700 others infected in an outbreak that started eight months ago.

The largest Ebola epidemic in history swept through Sierra Leone, Liberia and Guinea in 2013-2016, killing more than 11,000 people. That outbreak prompted a global push to develop vaccines and treatments — and some, including a protective shot developed by Merck and several antibody therapies for infected patients, have been deployed in the Congo outbreak.

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The technique, based on people exposed to the Ebola vaccine but not the Ebola virus itself, suggests protective therapies could be developed from people who are disease-free. Pixbay

Antibodies intended for treatment are normally collected from the blood of people who have survived infection. But they can also be tricky to obtain and carry heightened risks such as potential persistent viruses or other pathogens.

The Oxford team decided to try using blood from trial volunteers who had been given an experimental Ebola vaccine and whose immune system had responded to the shot by making antibodies. They successfully isolated 82 antibodies taken from 11 volunteers in trial at Oxford’s Jenner Institute.

Also Read: NASA Wants Humans To Reach Mars By 2033

They found that despite having less time to develop, a third of the antibodies were effective at neutralizing a strain of Ebola known as Zaire — the one causing the Congo outbreak.

The scientists then made a cocktail of four of the antibodies to create a treatment, which successfully cured six guinea pigs of Ebola when it was administered three days after infection. (VOA)