Many experimental vaccines have shown some effectiveness against Ebola hemorrhagic fever which continues to affect Africa. But these monoclonal vaccines only work on one strain of the virus and there are six. An American laboratory has just presented the preclinical results of a new universal recombinant vaccine. An approach that could be extended to AIDS or Covid-19, according to the researchers.
Last November, the first vaccine against fever Ebola hemorrhagic was put on the market (Read our article below). This vaccine named Everbo, although considered very effective by the World Health Organization (WHO), However, only protects against the Zaire strain, which is at the origin of the recent epidemic outbreak in the Democratic Republic of Congo (DRC) and that of 2013 to 2016 which led to more than 11,300 deaths in West Africa.
Now there are six cash known Ebolaviruses: Zaire (Ebov), Sudan (SUDV), Bundibugyo (BDBV), Taï Forest (TAFV), Reston (Restv) and Bombali, the first four affect humans, the others only transmit the disease to the primates. If the Zaire strain is by far the most dangerous and virulent, with a mortality rate up to 90%, theemergence or the re-emergence of other strains remains possible. Hence the importance of developing a protective vaccine against all forms of virus.
What you will learn
A fake virus combining proteins from two different strains
This is precisely what researchers from the Cincinnati Children's Hospital Medical Center, whose preclinical results of a new recombinant vaccine appeared in the Journal of Virology, published by the American Society of Microbiology. Researchers have designed a bivalent particle similar to Ebola (VLP), a kind of " shell vacuum ”, and incorporated two glycoproteins of the Zaire and Sudanese strains into it.
These glycoproteins (GP), located on the membrane of the virus, trigger the fusion viral and cell membranes, thus allowing entry of virion in the cell. They are also the ones that trigger the production ofantibody and this is precisely the property sought in a vaccine. The VLP being empty of material genetic, it does not cause the multiplication ofARN viral in cells and therefore does not cause infection.
And now AIDS and Covid-19?
Researchers tested their vaccine on rabbits and found that it triggered the antibody production not only neutralizing the two strains contained in the VLP (Zaire and Sudan), but also against the Bundibugyo (BDBV) and Forêt de Taï (TAFV) strains. Other tests on macaques have shown an immune response against the Ebov, SUDV and BDBV strains, suggesting efficacy of the vaccine against multiple species of Ebola virus, the study says.
" Used alone or in combination with another vaccine, it may provide more durable protection and in the long term against different viruses "Says Karnail Singh, the lead author. The researchers hope to be able to extend this method to other viruses than Ebola for vaccines with a big spectrum Answer. " We are currently working on those of AIDS and Covid-19 "Reveals Karnail Singh to ABSMARTHEALTH.
The research was funded by Innovation Ventures, the technology marketing branch Cincinnati Children's Hospital, the Research Foundation of Cincinnati Children's and support from New Iberia Research Center, the University of Louisiana and the NIH.
What you must remember
- Vaccines against Ebola hemorrhagic fever virus only work against one strain.
- By making a fake virus with proteins from two different strains, the researchers found that their vaccine induced the production of antibodies against two other strains.
- Alone or in combination, this vaccine could offer more lasting protection against different viruses.
Finally a vaccine against the Ebola virus
Article by Julie Kern published on 16/11/2024
The European Commission has authorized the marketing of the first Ebola vaccine. A single injection will be enough to protect exposed populations and limit human-to-human transmission of the virus, which has already claimed tens of thousands of lives in West Africa.
We can finally protect humanity against one of the major scourges of recent years, the Ebola virus. On November 12, the European Commission gave its fire green for the marketing of the Ervebo vaccine, manufactured by the American laboratory Merck Shape and Dohme. This vaccine which had been prequalified in October by the European Medicines Agency (EMA) meets UN standards in matter security and efficiency. It is the first Ebola vaccine to receive this approval. “Five years ago, we had no vaccine or therapeutic treatments for Ebola. Ebola is now preventable and treatable thanks to a prequalified vaccine and experimental treatments ” says WHO director Tedros Adhanom Ghebreyesus in an AFP statement.
There was a long way to go for this vaccine, the first draft of which was made in 2003. That year, theepidemic Ebola is particularly deadly, the mortality rate reaches 90%. Since then, it has proven itself in the field and has been administered, without official authorization, to more than 236,000 people, including 60,000 caregivers. Started for 2025, the current Ebola epidemic already has more than 3,290 cases in the Democratic Republic of Congo. Six out of ten people died. Sixteen years after the first tests, the final formula is finally available for UN agencies and caregivers located in countries at risk.
Immunize the population with a single injection
The Ervebo vaccine is part of the family of live vaccines attenuated. That is, it is made up of an entire viral strain but unable to multiply and induce disease. Its role is to effectively stimulate the immune system to produce antibodies specific to the Ebola virus. Scientists used a genetically modified vesicular stomatitis virus: it can then make the glycoprotein envelope of the Ebola virus. This will be the target of the antibodies produced following the vaccination.
When the antibodies attach to the envelope of the virus, it will no longer be able to enter the cells to infect and replicate them. Very practical for caregivers on site, the vaccine requires only one injection to be effective. However, Ervebo only protects against the Zaire strain of the virus which rage in the Democratic Republic of Congo. Another vaccine will need to be developed to protect against the Sudan strain which is responsible for the historic Ebola epidemic.
To immunize the most people, the ring vaccination method will be preferred. It is a very simple vaccination strategy: anyone who has been in contact with a clearly diagnosed patient must be vaccinated. Added to this are "neighbors", that is to say people who have been in contact with relatives of a patient. They will also need to be vaccinated. This method favors social contacts rather than a geographical area. Because once the first symptoms declared themselves, the Ebola virus is spread from human to human speed big V.
Ebola, life and transmission
The Ebola virus is a filoviridae (family which also counts among its ranks the measles virus and mumps) particularly virulent. This family includes five species, all of which cause hemorrhagic fevers. The first appearance of the Ebola virus in humans dates back to 1976, along the river that gave it its name, in Sudan. In the wild, the Ebola virus is thought to live peacefully in the body of bat frugivores. Then other animals, like chimpanzees or gazelles, become contaminated by eating fruit or grass contaminated with faeces of the bat.
A human is then contaminated by close contact with blood or secretions of these dead or sick animals. Once the virus is in the human body, it can take up to 21 days before the first symptoms appear. Quite harmless, tiredness, headache and sore throat, they delay the diagnostic of the disease. The patient's condition progressively worsens, ranging from highly contagious skin sores to fatal hemorrhagic fever.
On average, 50% of those infected die from the disease. As soon as the first signs appear, a patient with the Ebola virus can transmit it to another human being by close contact with body fluids or with contaminated surfaces and tissues. The presence of the virus in a patient is confirmed by a blood Review for anti-Ebola antibodies and by the detection of genome viral by RT-PCR.
Another vaccine still in the experimental stage, manufactured by Johnson & Johnson, will also be tested in the field in mid-November. This nevertheless has a drawback, it requires a booster 56 days after the first injection. According to Nature, a request for approval for this second vaccine by the European Medicines Agency was submitted in early November.
Staphylococcus aureus, terror of hospitals Staphylococcus aureus, Staphylococcus aureus, is not an inherently dangerous bacterium for humanity. Most of the time, it only causes small, minor infections. But this sneaky one sometimes hides in hospitals, and takes advantage of an injury to fit into a weakened patient to colonize him and lead to sepsis. There is always time to subject her to antibiotics … but she is becoming more and more insensitive to the drugs that are opposed to her and is developing increasing resistance! © NIAID, Flickr, cc by 2.0
Neisseria meningitidis, main responsible for meningitis Meningitis knows not one, but several culprits. Among the most serious bacterial forms, the main defendant is Neisseria meningitidis, involved in 90% of cases. If there were no treatment, the infection would almost certainly be fatal. Despite antibiotics, one in five newborns and one in four adults die from this meninges infection. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0
The hepatitis B virus, this terribly infectious STD We talk about it less than HIV, however, it deserves our full attention. The hepatitis B virus is transmitted a hundred times better than the AIDS virus during sex and then attacks the liver cells. Most often, the disease does not progress much and the patient feels nothing. But sometimes hepatitis becomes chronic, as in more than 300 million patients, and gradually destroys the liver cells, leading to cirrhosis or liver cancer, which is very difficult to treat. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0
The rabies virus, the bite that causes carnage Thanks to the work of Louis Pasteur, rabies has declined significantly around the world. There were still more than 50,000 human deaths on the Planet in 2004 due to the rhabdoviridae family virus. Transmitted by bite, it rushes straight into the nervous system and wreaks havoc there so much that death is almost inevitable. Fortunately, the vaccines are here! © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0
Yersinia pestis, the bacteria responsible for plague epidemics Who does not remember these History courses evoking the plague epidemics in the Middle Ages? Behind all of this hides Yersinia pestis, a bacterium that first attacks rodents before attacking humans. The disease most often existing in bubonic form (a bubo being an inflammation and the enlargement of a lymph node), it can develop into septicemic plague and become more deadly and more contagious. In the history of humanity, its mortality is difficult to assess but it is very probably responsible for more than 100 million victims. © NIAID
Bacillus anthracis, the bacteria behind anthrax Anthrax, or anthrax, is caused by a bacteria called Bacillus anthracis, or anthrax. Most often, it enters the body through a wound in the skin. The body then manages to get rid of it on its own. When the bacteria's spores are swallowed or breathed, however, it's a whole different story. By air, it is not far from being fatal in 100% of cases. That’s why it inspires bioterrorists so much. © Janice Haney Carr, CDC
Hantaviruses and their terrible pulmonary syndrome Hantaviruses are a little different from the other pathogens presented in this slideshow: they prefer to attack rodents but, sometimes, unfortunately, they can infest a Man. In these cases, their action can be overwhelming. Causing hemorrhagic fevers or hantavirus pulmonary syndrome, they are occasionally very aggressive and commonly fatal. The Sin nombre virus, or Sin Nombre virus (SNV), which we see in the picture, rarely strikes, but surely. © Brian et al., CDC
The Marburg virus, a real killing machine The Marburg virus is designed to kill but is still a little less deadly than its cousin Ebola. Also causing hemorrhagic fevers, this filovirus kills more than 80% of the people it infects. Its transmission from Man to Man is nevertheless relatively difficult since it requires very close contact between individuals, with transmission by stool, vomiting, urine or saliva. © Frederic Murphy, CDC
The dengue virus is gaining ground It is far from the deadliest and most pathogenic on this list, but it should not be overlooked. The dengue virus, transmitted by Aedes mosquitoes, infects between 50 and 100 million people worldwide. For 500,000 people, especially children, the disease presents itself in a severe form which takes 10,000 souls. A major problem: it has been on the increase in recent decades. It was limited to nine countries before 1970 and now affects around 100 states. © Sanofi Pasteur, Flickr, CC by-nc-nd 2.0
Ebola, the virus with the highest mortality? Known since 1976, the Ebola virus, named after a Congolese river, is one of the most deadly. Some of its strains cause hemorrhagic fevers which kill in 90% of cases. This virus has caused several epidemics in Africa, particularly in Sierra Leone, Guinea and Liberia, killing several thousand people. Unfortunately, there is no preventive or therapeutic treatment for this terrible plague. © Frederic Murphy, CDC
The Spanish flu virus, this devastating epidemic of 1918 The year 1918 was a very deadly one, on the one hand because the fighting was still taking place in Europe and even beyond, on the other hand because a particularly virulent strain of influenza H1N1 prevailed in the whole world. It is believed to have infected one in two Terrans, or 500 million people at the time, and is estimated to have killed between 30 and 100 million people. A real weapon of mass destruction … © Terrence Tumpey, CDC
Clostridium botulinum, the bacteria that poisons botox Clostridium botulinum has a technique of its own for committing murders: the bacteria prefer poisoning. Indeed, it produces one of the most powerful toxins in the world, botulinum toxin. This molecule resists high heat and the acidity of the digestive system, so that, when ingested, it integrates the circulation and will block nerve communication, resulting in paralysis which is sometimes fatal. © CDC
Mycobacterium tuberculosis, the deadly agent of tuberculosis Having become rare in France as in rich countries since the introduction of BCG, tuberculosis nevertheless continues its deadly work throughout the world. In 2010 alone, the bacteria responsible, Mycobacterium tuberculosis, infected 8.8 million people and killed 1.4 million of them, attacking their lungs. The bacteria has been rife for 3 million years. © Janice Haney Carr, CDC
The H5N1 virus A, the source of the world-shaking flu Appearing in 1997 in Hong-Kong, it was only 9 years later that the H5N1 flu caused panic to the whole Earth. The virus (here in gold in dog cells), transmitted to humans only by contaminated birds, is fatal in 60% of cases. In August 2012, WHO counted 608 people who had contracted the virus since its inception, for 359 dead, even if many mild or asymptomatic cases could have been not counted. Scientists remain concerned, however, because the pathogen still circulates in nature and we know that a few mutations could be enough for it to become contagious in the human species. In this case, the deaths could be counted in millions… © CDC
HIV: the AIDS virus and its 30 million victims Since 1981 and the date of its discovery, HIV (the little green balls in the picture) has killed around 30 million people worldwide and is still spreading. This retrovirus generates AIDS (Acquired Immunodeficiency Syndrome) and especially ravages poor countries, those of the African continent in the lead. However, there are therapies that block the progression of the virus in the body and allow patients to live with HIV without declaring AIDS for very long years. But these are struggling to export outside of the rich countries. © Goldsmith et al., CDC
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