Faced with the emergency, scientists are calling for speeding up testing procedures and doing without the usual animal tests. A laudable strategy, but one that could prove counter-productive at best, and at worst cause death.
While the epidemic is an increase in an endemic disease or the appearance of a large number of patients where the disease was … “data-url =” https://news.google.com/ health / definitions / vie-epidemie-3837 / “data-more =” Read more “>epidemic of Covid-19 continues to gain ground, scientists around the world have embarked on a speed race at vaccine. More than 20 possible candidates are under development, including one from the Institut Pasteur which started testing on mice on March 11. The most advanced is that of Start-ups, digital and biotechnologies
The … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/d/6/e/d6eab33032_90352_shutterstock-stock-rocket.jpg “data-url =” https: / /news.google.com/tech/definitions/tech-start-up-15740/ “data-more =” Read more “>start-up Moderna, organized jointly with the NIH (National Institute of Health, American equivalent of Inserm), which started phase 1 trials with volunteers on March 16. A trial started in record time, just a few weeks after the availability of the genome of Sars-Cov-2.
15 to 20 years to develop a vaccine
Normally, get a effective vaccine, non-toxic and usable takes between 15 and 20 years. We must first develop a formula with the chemical and pharmaceutical prerequisites, conduct studies of the factors that influence immunogenicity
The more the response will be strong and induced … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/3/d/c/3dc6039c28_50084159_vaccin4jpg.jpg “data-url =” https : //news.google.com/sante/definitions/medecine-immunogenicite-13234/ “data-more =” Read more “>immunogenicity In animals, assess the This toxicity also depends on the dose of xenobiotic necessary for … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/a/c/9 /ac93ff44a1_50035323_symbole-toxique-yves-guillo-domaine-public.jpg “data-url =” https://news.google.com/sante/definitions/medecine-toxicite-6517/ “data-more =” Read more ” >toxicity of the vaccine in animals, then in humans, and finally, testing its effectiveness on a large scale. But, faced with the emergency, the pressure governments and health authorities, some call for speeding up procedures. European Commission President Ursula von der Leyen said Tuesday she hoped for a vaccine against new coronavirus before’autumn. More reasonably, Moderna promises that its vaccine will be ready at best by mid-2021.
When the vaccine facilitates viral infection
But is it a good idea to skip the steps? A vaccine is not harmless: it is most often a The infection function allows the virus to be introduced into program files, into files … “data-url =” https: //news.google.com/tech/definitions/informatique-virus-informatique-2434/ “data-more =” Read more “>virus disabled or weakened, and can in some cases worsen the disease it is supposed to prevent. Peter Hotez, Dean of the National School of Tropical Medicine Baylor College of Medicine and who worked on the SARS epidemic in 2003, found that some vaccinated animals developed examples of symptoms
Symptoms can affect different organs:
muscle, joint pain, headache, digestive problems, vision problems, rashes … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/e/8/8 /e882bacd5b_96032_symptome-femme-mal-tete.jpg “data-url =” https://news.google.com/sante/definitions/medecine-symptome-834/ “data-more =” Read more “>symptoms even more severe when exposed to the virus due to a weakened immune system. This is called a “facilitation of infection by the structure of an antibody.
An antibody is a protein complex. If every organism with an immune system codes for billions of different antibodies, they all have the same global characteristics. These are … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/a/5/4/a543c37e56_50034150_ Antibody-yohan-gfld.jpg “data-url =” https: //news.google.com/sante/definitions/medecine-anticorps-93/ “data-more =” Read more “>antibody “(Antibody-dependent enhancement or ADE in English).
Conventionally, the virus initiates the cycle of infection by fixing Roles of proteins
Proteins can perform a wide variety of functions within the cell or organism.
They can have:
a structural role (like actin or tubulin which … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/4/6/e/46e94f9da7_50034188_actine-thomas-splettstoesser -cc.jpg “data-url =” https://news.google.com/sante/definitions/biologie-proteine-237/ “data-more =” Read more “>protein spike-like viral surfaces to target cell receptors. In doing so, these proteins induce an immune response where surface antibodies will inhibit certain elements of the cell necessary for the virus such as the receptor binding site or the. We speak of dipeptides, tripeptides when … “data-url =” https://news.google.com/sante/definitions/biologie-peptide-292/ “data-more =” Read more “>peptide of The melting point of water, in other words the temperature at which the ice … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/7 /d/0/7d0df59f3c_82086_fusion.jpg “data-url =” https://news.google.com/sciences/definitions/physique-fusion-15305/ “data-more =” Read more “>fusion. However, in certain circumstances, these antibodies will on the contrary bind with the tips of the virus and facilitate their entry into the cell, or cause a replication and increased infection.
The best known example is that of a vaccine against respiratory syncytial virus (RSV, against Bronchiolitis, a childhood respiratory infection
Bronchiolitis … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/6/4/d/64df840b26_53924_bronchiolite.jpg “data-url =” https: // news. google.com/sante/definitions/medecine-bronchiolite-14333/ “data-more =” Read more “>bronchiolitis) developed by Pfizer in the 1960s, which led to several serious cases pneumonia in children, resulting in the deaths of two of them. The same phenomenon has been reported with a dengue vaccine from Sanofi or the West Nile virus. It is also seen in animals for the Flu Agent
The infectious agent is a virus from the Orthomyxoviridae family, the genome of which consists of eight RNA segments. These RNAs are grouped in the same viral particle, … “data-image =” https://cdn.futura-sciences.com/buildsv6/images/midioriginal/8/f/5/8f5a87906d_117966_grippe-fievre.jpg “data -url = “https://news.google.com/sante/definitions/medecine-grippe-3442/” data-more = “Read more”>influenza, Zika virus… and the coronavirus like the Sars.
Reliable animal models too long to develop
The exact mechanisms of these side effects and why some people are affected and others are not yet known. ” But the best way to insure against this risk is to test the vaccine on animals “, Assures Peter Hotez to the agency Reuters. And this is where the second problem arises. Because to have tests that can be extrapolated to humans, you must first obtain mouse lines that have been genetically engineered to match their immune response to that of humans.
A process which takes a lot of time and which Moderna did without. The company points out that its vaccine poses a lower risk of facilitating infection by antibodies, because it only uses proteins from viral surfaces, and not a whole virus deactivated. However, neither Moderna nor a good number of start-ups in the race have never produced a vaccine, which leaves a doubt on their ability to grasp the phenomenon.
There is no reason to put people at risk in a study for an ineffective vaccine
Speed versus security, an assumed choice
” There is no reason to put people at risk in a study for a vaccine ineffective “Warns Karen Maschke, researcher at the Hastings Center, a non-partisan think tank, on the site STAT. ” If, against all odds, this hasty project works, then society will have to be even more attentive in monitoring and tracking the people who benefit from it. “Adds Arthur Caplan, head of medical ethics at Grossman School of Medicine from New York University. Arguments that do not seem to outweigh the panic triggered by the Covid-19 epidemic.
In a closed meeting, officials from the World Health Organization (Health: what is WHO?
As stated in its constitution, WHO aims to bring all people to the highest level of health … “data-image =” https://cdn.futura-sciences.com/buildsv6/ images / midioriginal / c / 0/3 / c0318e9153_101519_oms-logo.jpg “data-url =” https://news.google.com/sante/definitions/medecine-oms-4321/ “data-more =” Read more “>WHO) have agreed to allow testing on humans before results on animals are known, reports a Reuters participant. The institutions are said to be ready to assume the risk of a few serious cases in exchange for a quick vaccine that will, at best, not be available until the peak of the epidemic.
What you must remember
- Laboratories around the world have embarked on a speed race for the Covid-19 vaccine, even without the usual tests in animals.
- These vaccines can then, in some cases, facilitate infection with the virus and lead to worsening of symptoms.
- Companies also lack reliable animal models for testing their vaccines.
- The urgency and the pressure are such that these risks are no match.
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