Wednesday, December 2

Is this the beginning of a revolution in mRNA vaccines? | Coronavirus


TThe last few months have drawn public attention to a number of scientific terms. We had to digest R (the reproduction number of a virus) and PCR (the polymerase chain reaction test method). And now there is mRNA. The latter has been featured a lot in recent news reports due to the spectacular results of two new coronavirus mRNA vaccines. It stands for “messenger ribonucleic acid,” a rather familiar label if you studied biology at the O or GCSE level, but otherwise hardly a household name. Even in the field of vaccine research, if you had said as recently as 10 years ago that you could protect people from infections by injecting them with mRNA, it would have caused some puzzled looks.

Essentially, mRNA is a molecule used by living cells to convert the sequences of genes in DNA into proteins that are the building blocks of all its fundamental structures. A segment of DNA is copied (“transcribed”) into a fragment of mRNA, which in turn is “read” by the cell’s tools to synthesize proteins. In the case of an mRNA vaccine, the mRNA of the virus is injected into the muscle and our own cells read it and synthesize the viral protein. The immune system reacts to these proteins, which by themselves cannot cause disease, as if they had been transmitted by the entire virus. This generates a protective response that, we hope, will last for some time. It is so wonderfully simple that it almost seems like science fiction. But we learned last week that it was true.

It is remarkable that observations originally made in cell cultures in a Petri dish have been translated into real life. At the same time, it is not entirely surprising that the first two Covid-19 vaccines that announced the results of phase 3 were based on mRNA. They were the first to get out of the blocks because, as soon as the genetic code of Sars-CoV-2 was known (it was published by the Chinese in January 2020), companies that had been working on this technology were able to start producing the virus’s mRNA. Making conventional vaccines takes much longer.

The impressive performance of these new vaccines may outshine that of others currently in development. It depends on how effective those alternative approaches are, and the results will start to get thick and fast. Beyond that, however, is the question of whether mRNA could represent the future of all vaccines. If a coronavirus vaccine can be created so quickly and so well with mRNA, why not use this approach across the board? Bottom line: will mRNA become the default platform for vaccines from now on? That would mark a breakthrough in disease prevention.

We will just have to wait and see if it happens. Even if we assume that the full detail of the results, when they arrive, corroborates the headline figures, there are things that only time can reveal. How long will protection last, especially for those most at risk? Are these vaccines efficient enough not only to prevent recipients from getting sick when exposed, but also to prevent them from becoming infected altogether or, failing that, to reduce transmission of the virus to other people?

The other key criterion by which we judge any new vaccine technology is safety. Unlike drugs, which are given to treat sick people, vaccines are offered to everyone. Side effects are only tolerable if they are fairly mild and short-lived – most people will accept a second of sharp pain followed by a tender upper arm and a slightly discolored feeling for a day or two, but that’s about it. . Serious diseases caused by vaccines should preferably be non-existent, or at least extremely rare.

At first glance, the mRNA should be safe. After all, it is found in abundance in every cell in our body all the time. It is also a very fragile molecule. It breaks down very easily and breaks down quickly using proteins designed to do that, which seem to be everywhere. Working with mRNA in the lab is a nightmare because it keeps disappearing. On this basis, it should not remain in the body for long after the injection.

The fact that mRNA is genetic material could lead you to think that there is some risk of genetic side effects. However, in human cells, while DNA is regularly transcribed into RNA, the opposite is not true: RNA cannot go back into DNA and alter our genes. (In fact, making DNA from RNA, which is called reverse transcription, is something that only a certain type of virus, such as HIV, can do). Ultimately, however, confidence in the safety of vaccines comes from experience, and the same will be true for mRNA. What’s reassuring is that it has already been tested for safety in tens of thousands of study subjects. In no time, they will turn into millions, and assuming no unexpected problems arise, the sense of calm will increase.

Whether or not mRNA becomes the preferred way to make novel vaccines, it is clear that a global disaster on the scale of the pandemic spurs innovation at a much faster rate. This is not just the consequence of all the resources and funds made available to those who have solutions that might normally be viewed with more skepticism; it is also driven by the remarkable things that human beings can accomplish when pushed together by circumstances and given a common purpose. While we like to praise individual heroes and leaders, scientific advancements like mRNA vaccines are always the product of the collaborative efforts of many people with diverse abilities and backgrounds. Bringing vaccines to the clinic also requires large numbers of courageous and altruistic volunteers to participate in clinical trials.

Taking a step back, highlight a fact. At the beginning of November, we still didn’t know if any The vaccine could help us overcome this terrible disease. As the month draws to a close, we are confident you can. However, mRNA vaccines appear in the history books, that in itself is something to marvel at. Human ingenuity, invention, and hard work mean that we are finally on our way out of this mess.

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www.theguardian.com

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