Tuesday , September 21 2021

Vaccine miracle: how scientists fought the battle against Covid-19 | World news

I.In the early afternoon of January 3 this year, a small metal box was delivered to the Shanghai Clinical Center for Public Health, addressed to the virus expert, prof. hangang Jongzhen. Inside, packed in dry ice, there were swabs from a patient suffering from a new, occasionally fatal respiratory illness affecting the city of Wuhan. Exactly what causes a frightening increase in the number of cases, the medical authorities wanted to know? And how did the disease spread?

Hangang and his colleagues started working. For the next 48 hours or so, he and his team used advanced sequencing machines to detect the RNA – the genetic building blocks – of the virus, which they believed was responsible for the outbreak. Decoding 28,000 letters of this RNA – which acts as letters of human DNA – will give a precise indication of the nature and behavior of the new pathogen.

And in the early hours of January 5, Hangang and his team completed their task. The virus, they discovered, was a previously unknown coronavirus, which was most closely linked to the one that caused the fatal outbreaks of severe acute respiratory syndrome (SARS) in China several years earlier. And just like Sars, the new virus apparently spread from person to person. “So it must have been very dangerous,” Hangang said.

Prof.  Hangang Yongzhen

Prof. Hang Jongzhen’s breakthrough, the publication of the Sars-Kov-2 virus genome in January, gave science a chance to fight back. Photo: ChinaCDC.CN

Days after his progress in sequencing, the results of the hangang were published on virological.org – giving the world the first record of a pathogen that has since killed more than 1.5 million people and convulsed nations with locks, restrictions on travel and economic turmoil. However, Hangang’s discovery had more than just a harbinger of chaos and death. The early discovery of the structure of the virus responsible for Covid-19 on his team – as the disease was later named – gave science a chance to fight back. The result was an international effort to see a vaccine for the disease in the public eye for the first time this week.

It is a remarkable achievement. Going from the discovery of a new deadly virus to the creation of a tested vaccine that can block its effects in less than a year is unprecedented in scientific history. For some, it is simply a medical miracle, as it suggests – if nothing else – that the world can give up the worst of its Covid-19 problems sooner rather than later. As Stephen Griffin of the University of Leeds Medical School puts it: “The incredible advances in vaccine use in humans are certainly setting a new standard for what can be achieved when sufficient resources and a scientific focus on global health are available.”

The Covid-19 virus, now known as Sars-Cov-2, is a spiked ball of genetic material coated with fatty chemicals called lipids and is 80 billionths of a meter in diameter. These spikes are made of a protein that binds to receptors on cell surfaces in our bodies and then lubricates the RNA of the virus in them. Once inside, that RNA is inserted into the replication machine of our cells and makes multiple copies of the virus. These erupt from the cell and the infection spreads.

By sequencing the virus genome, Hangang provided vital information that has since allowed scientists to isolate and replicate individual parts of the virus and use these components to create vaccines. “What Hangang did was absolutely critical of what followed,” he said. Adam Finn of the University of Bristol. “Without the information he provided, no one could have started working on vaccines.”

The spike protein that plays such a key role in allowing replication of Sars-CoV-2 has quickly become the focus of attention of most vaccine manufacturers. The researchers reasoned that if a person could be helped to set up a powerful immune response that would prevent spike proteins from slipping into our cells, the virus would not have progressed. To do so, they had to find ways to put pieces of spiky protein into the body to stimulate the production of antibodies that would attack them, a tactic that has since been adopted by most Covid-19 vaccine projects – albeit in different ways.

“The key point is that you do not need a real virus in your hands these days, you only need 28,000 letters of its genetic code,” said David Matthews, a corovirus expert at the University of Bristol. “You can send a message to someone and it will fire the start gun.”

Ozlem Tureci and Ugur хahin

Ozlem Tureci, left, and Ugur хahin from BioNTech. Supported by Pfizer, their vaccine is 90% effective in preventing people from getting sick. Photo: Wolfgang Eilms / FAZ Photo

One group prepared on the front line was based in Frankfurt, where Ozlem Tureci and her partner Ugur хahin founded BioNTech in 2008 to make RNA vaccines tailored to fight cancer – an expertise that could be quickly transferred to the battle against Covid. -19, they understood.

Using the genetic sequences provided by Hangang, BioNTech – backed by pharmaceutical giant Pfizer – was able to pack RNA pieces of protein for spiky viruses and inject them into humans. Infected by cells in our bodies, these RNA droplets instruct our cell replication machines to produce spiky protein particles. When detected by our immune system, this triggers the production of antibodies. A similar approach was adopted by the American biotechnology company Moderna in the development of the vaccine.

“It is a new technology, but it is also very simple,” said Prof. Peter Openshau of Imperial College London. “It basically involves basic chemical synthesis and not much more. You do not need to carefully aim for tissue cultures, keep your pots very sterile and so on. You just make a chemical strand of RNA and put it in a person. “That is the key reason why BioNTech and Moderna got such fast results.”

It is also very promising technology that can be used very quickly in the future, Openshau added. “It’s almost like a plug and play vaccine. You can select other RNA fragments and create combined vaccines with incredible ease. For example, you can combine influenza RNA with Rovid Covid and make a combined vaccine against both diseases. “This technology is revolutionary.”

A different approach was adopted by scientists led by prof. Sarah Gilbert of the Engineering Institute at Oxford University. Following the Ebola outbreak in 2014-2016, researchers there have been making plans to create a vaccine for any new disease that may appear in the world – in the shortest possible time.

Professor Sarah Gilbert of the University of Oxford

Prof. Sarah Gilbert, of the University of Oxford, whose team developed a successful vaccine with drug giant AstraZeneka. Photo: Con Cairns / University of Oxford / PA

To do this, they developed a common cold virus that infects chimpanzees so that it can not cause infection in humans, but can also be replicated to carry genetic designs for pieces of the virus that you want to train your immune system. to attack them. Armed with this technology, all the Oxford scientists – later backed by pharmaceutical giant AstraZeneka – had to do was slip the genetic guidelines for the spike protein into their engineering virus and begin testing.

The Moderna, BioNTech, and Oxford-AstraZeneca vaccines were the first to be found in clinical trials – but there are 200 other vaccines being tested worldwide. The question was: will any of them work? For months, the international community has been watching and advancing clinical pathways in the hope that a vaccine that is at least 50% effective in blocking Covid-19 can be produced.

For his part, Sahin was convinced the BioNTech vaccine would work, but there was no proof he was right until he received a call – at 8pm on Sunday, November 8 – from Pfizer CEO Albert Burla. He was just told by an independent monitoring committee studying the results of the Phase 3 vaccine trial that it had exceeded expectations and was more than 90% effective in preventing people from getting sick.

“It was the second truth when a lot of weight fell from our minds,” Shahin said. Хahin and Tureçi, both from Tetovo, celebrated with cups of black tea. The rest of the world reacted more enthusiastically. “Having this news less than a year after Covid-19 appeared is a remarkable achievement and proof of the extraordinary global research response,” said Remaremi Farrar, CEO of Wellcom Trust. “Effective vaccines will change the basis of this pandemic.”


More good news was to follow. Moderna vaccine trials also suggest it may provide strong immunity, while Oxford-AstraZeneka test results – despite some confusion over initial dosing levels – also suggest it would be a powerful tool in the fight against Covid. 19.

“Somehow I’m surprised that so far everything has gone smoothly,” said Eleanor Riley, a professor of immunology at the University of Edinburgh. “Normally, when you start a new vaccine, you expect something, at some point, not to turn out as expected. “However, things have moved smoothly – which is great.”

However, a number of key issues still need to be addressed. None of the early vaccines showed the possibility of reducing the spread of the disease in the population. “Vaccinated people, while protected from severe symptoms, can still transmit the infection to others and that is a key issue,” Riley said.

Nurse at Royal Free Hospital, London

A nurse at Royal Free Hospital, London, is taking part in staff training to administer the Pfizer BioNTech vaccine. Photo: Yui Mok / PA

“If we want to have a future without covids, then we need something that really suppresses transmission. If not, then the virus will circulate non-stop and anyone who has not been vaccinated will always be at risk. In the short term, this is not a problem. We just need to save lives. “But in the long run it will be a problem.”

However, an encouraging hint is given by the Oxford-AstraZeneka vaccine. During his trials, participants were routinely tested to see if those who received the vaccine had a lower viral load in the throat and nose than those who received a placebo. Early signs suggest that they have a lower burden and are therefore less likely to transmit the virus. “I think it would be surprising if the vaccines we received no longer restrict transmission in some way,” Riley added. “We need to find out soon.”

However, resolving other issues will take some time. It is unclear how long protection against Covid-19 vaccines will last. Some reports suggest that antibody levels begin to drop significantly only a few months after a person receives Covid-19, suggesting that vaccine-induced antibody levels may also disappear rapidly. However, this idea was deleted by Openshaw.

“From the analysis of modern and other vaccines, it is clear that vaccines elicit far stronger immune responses – at least in terms of antibody production – than are triggered by a natural infection with the virus. “So the antibody level has to be pretty long-lasting.”

It was a remarkable journey that, at the moment, seems to have a happy ending – although scientists are clear that there will be bumps in the road. Vaccine adverse reactions will affect some individuals as global supply chains tighten. The key point is that we now have vaccines to deal with Covid-19 and it looks like they will work. That is the beginning.

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