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United States President Donald Trump’s reelection campaign took off with him telling potential voters that a coronavirus vaccine will be ready by the end of 2020, even as European leaders pledged to raise $ 8.3 billion. to “initiate unprecedented global cooperation” between scientists, industry, governments and philanthropies for vaccine development.
Global efforts to develop a vaccine against coronavirus disease (Covid-19) have progressed at an unprecedented rate with the aim of stopping the spread of the pandemic, which has infected 3.5 million people, killed 250,000 and destroyed economies. global in four months.
At least 120 vaccine projects are in various stages of development since China shared the Sars-CoV-2 gene sequence, which causes Covid-19, with the World Health Organization (WHO) on January 12, 2020. Of these, seven have entered human trials to assess the safety and efficacy of the vaccine in healthy volunteers, according to the WHO. Another 82 are in preclinical testing phases in animals, and at least two have been found to protect monkeys from infection.
Johnson & Johnson, who was cited by Trump as an example of the vaccine’s success, said last month that it will be ready to produce 600 million to 900 million doses of its potential vaccine by April 2021 if human trials will begin in September. . planned. Pfizer and the German company BioNTech said that if their human tests are successful, they can produce millions of doses by the end of 2020.
Vaccine development, on average, takes 10.71 years from the preclinical phase, and has a 6% chance of entering the market, according to a study in a peer-reviewed journal, PLOS One. The development includes at least three trials in to assess their safety, dosage, and the strength and duration of protection they offer, followed by production, licensing, vaccine implementation, and post-marketing surveillance plans.
“With Covid-19, the goal is to develop, test, and manufacture a vaccine on a scale of hundreds of millions of doses within 12 to 18 months. Since the vaccine will be needed very quickly, companies have taken an unprecedented approach. Since approval for an emergency use of the vaccine is expected, they will begin mass manufacturing as soon as the Phase 2 trials are complete and they move on to Phase 3, and in doing so they risk failing Phase 3. In such cases, consortia and countries fund risk reduction and provide market commitments, “said Dr. NK Ganguly, former director general of the Indian Council for Medical Research (ICMR).
Pune-based Serum Institute of India began work 10 days ago in parallel manufacturing of the human safety trials, the experimental Oxford vaccine, ChAdOx1 nCoV-19, at your own risk. IBS plans to start manufacturing the ChAdOx1 vaccine in anticipation of clinical trials in the UK that will be successful in September / October. IBS will start manufacturing at your own risk to speed up manufacturing and will have enough doses available if clinical trials work, “IBS CEO Adar Poonawalla said in a statement.
Last week the WHO organized a meeting of vaccine manufacturers and national regulatory authorities in its Southeast Asia region, which includes India, Indonesia and Thailand. All three countries are among the world’s largest vaccine manufacturers.
“The manufacturing capacity that exists in the region is of the quality and scale required to produce and deploy a Covid-19 vaccine worldwide. This region is a vaccine manufacturing powerhouse, and now it must also play a leading role in overcoming the ongoing pandemic, ”said Dr. Poonam Khetrapal Singh, WHO regional director for Southeast Asia. At the virtual meeting, leading manufacturers in India, Indonesia and Thailand discussed timing and production capacity, while regulatory bodies discussed how to speed up processes to enable the large-scale production and deployment of Covid-19 vaccines. At the end of the year.
“The way this pandemic progresses, we have no choice but to have an emergency vaccine within eight months, we cannot afford to wait for years. In the case of Covid-19, we already have some experience of SARS platforms CoV-1 and MERS, which have previously been used to administer other vaccines, are the same with the tested adjuvants. [a substance which increases the body’s immune response to an antigen], which could be used. So, considering the fact that we are not starting from scratch, it is in the realm of possibility, ”said Dr. Ganguly.
Last month, WHO launched the COVID-19 Access Tool Accelerator, bringing together key global health actors, private sector partners, and other stakeholders to accelerate the development and production of essential Covid health technologies. -19, including vaccinations, and to help ensure fair access.
Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, recently said that it is “within the scope of the possibility” to have a vaccine widely available by January, but only if pharmaceutical companies are willing to take the risk of starting To increase. vaccine production before it is fully tested and approved.
Vaccines have led to the global eradication of smallpox and have eliminated polio from most countries in the world, except Pakistan, Afghanistan and Nigeria, where it remains endemic. However, vaccines for diseases like HIV remain elusive after two decades of effort.
“All countries are preparing for a safe transition to a new normal in which social and economic life can function in the midst of low or no Covid-19 transmission. No country is safe until we are all safe, for which we need an effective vaccine that is accessible to all, ”said Dr. Khetrapal Singh.
Coronavirus vaccines: types and methods
Covid-19 vaccines use a wide variety of platforms and techniques to train the immune system to identify the Sars-CoV-2 virus and block or destroy it before it infects the body.
Most vaccines feed immune cells, a signature of the unique spike protein on the surface of the Sars-CoV-2 virus, which it uses to enter human cells to cause infection.
An effective vaccine is one that generates neutralizing antibodies, which store the genetic model of the virus to provide lasting protection.
At least eight types of vaccines are being developed that depend on different viruses or viral parts.
Virus vaccines
At least seven teams are developing vaccines using the Sars-CoV-2 virus in a weakened or inactive way, such as those used against measles and polio. Sinovac Biotech in Beijing is testing an inactive form of Sars-CoV-2 in humans.
Weakened virus: A virus is conventionally weakened for a vaccine by passing through animal or human cells until it detects mutations that make it less capable of causing disease. Codagenix in New York is working with the Pune-based Indian Whey Institute to weaken SARS-CoV-2 by altering its genetic code so that viral proteins are produced less efficiently.
Inactivated virus: The virus becomes non-infectious using chemicals, such as formaldehyde or heat.
Nucleic acid vaccines
About 20 projects are using genetic material from coronaviruses (DNA or RNA) to provoke an immune response. Nucleic acid is inserted into human cells, which then produce copies of the virus protein. Most coronavirus vaccines encode the spike protein of the virus.
RNA and DNA-based vaccines are safe and easy to develop: producing them involves producing only genetic material, not the virus. But they are not proven: no licensed vaccine uses this technology
Viral vector vaccines
A weakened virus, such as measles or adenovirus, is genetically engineered to make coronavirus proteins in the body without causing disease. There are two types of weakened viruses, those that can still replicate within cells and those that cannot, because the key genes have been turned off.
Viral vector replication (such as weakened measles) – The recently approved Ebola vaccine is an example of a viral vector vaccine that replicates within cells to elicit a strong immune response. The vaccine is safe, but existing immunity to the vector could reduce the effectiveness of the vaccine.
Non-replicating viral vector (such as adenovirus): No licensed vaccine uses this method, but they have a long history in gene therapy. Booster injections may be needed to induce lasting immunity. Johnson & Johnson, based in the USA USA, and Oxford University are using this approach.
Protein-based vaccines
Coronavirus proteins, from protein fragments or protein layers, which mimic the outer layer of the coronavirus, are injected directly into the body.
Protein subunits: Twenty-eight teams are working on vaccines with viral protein subunits, and most of them are focused on the spike protein of the virus or a key part called the receptor binding domain. Similar vaccines against the Sars virus protected monkeys against infection, but they have not been tested in people. To function, these vaccines may require adjuvants or immunostimulatory molecules administered in conjunction with the vaccine, as well as multiple doses.
Virus-like particles: Empty virus shells mimic the structure of the coronavirus, but are not infectious because they lack genetic material. Five teams are working on “virus-like particle” vaccines, which can trigger a strong immune response, but can be difficult to manufacture.
Source: Nature
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