The coronavirus is mutating

According to Peter Thielen, a molecular biologist at the Johns Hopkins Laboratory of Applied Physics, SARS-CoV-2 is mutating.

Among the thousands of samples of the long chain of RNA that makes up the coronavirus, there are 11 mutations that have become quite common. But as far as is known now, it is always the same virus that infects people, which would mean that there is only one strain.

Around the world, hope for a return to normalcy is pinned on a vaccine ―the ultimate weapon―, as it’s been called by officials like Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. But it’s still unclear how successful a vaccine against SARS-CoV-2, the virus that causes COVID-19, can be.

In this way, a lot will depend on how the virus mutates. Broadly, there are two ways mutations can play out.

The first one, the coronavirus is unable to evade a vaccine. That could mean a successful vaccine could stop the virus dead in its tracks, but only if the virus doesn’t mutate its way around the shot. In this way, like all viruses, SARS-CoV-2 is mutating as it passes from person to person. A mutation is just a change in a virus’s genetic code. Most mutations don’t really change how the virus functions. Besides, since vaccines work by prompting the body to develop antibodies ―which neutralize the virus by binding to it in a very specific way―, scientists are watching to see if mutations will affect this interaction. If they don’t, then there is hope that a vaccine won’t need constant updating. For example, measles mutates just as fast as flu and coronavirus, but the measles vaccine from 1950 still works today. To enter a cell, the measles virus uses certain of its proteins that are unable to mutate even slightly without breaking. The vaccine targets those parts, so any mutation that would evade the vaccine would mean that the virus can’t infect other cells, so the vaccine has the measles virus cornered.

The second one, mutations make vaccines less effective over time. If the virus mutates in a way that prevents antibodies from binding, it could make a lasting universal vaccine difficult to create. What will happen in many viruses is you’ll get infected by Strain A; your immune system learns to recognize that surface protein, but then the virus is able to mutate in such a fashion that it still performs its function but make it so that your antibodies against Strain A no longer recognize Strain B. That is what happens with the flu: the virus’s antigens mutate so much that they evolve into different strains, each requiring a slightly different vaccine. Scientists continuously develop vaccines to target those new strains. In spite of that, the vaccines offer only partial immunity to the various flu strains that spread each year. If that happens with the coronavirus, researchers will have to rush to produce and administer new vaccines as novel strains of the virus naturally arise.

For a brand-new virus like SARS-CoV-2, there is no widespread immunity. This virus is encountering few immune hosts who could halt its spread. Since the virus doesn’t need to change to survive, mutations that could modify the shape of the antigens ―if they exist at all―, are likely rare, and will stay rare. But if people become immune to the dominant strain, either by fighting off the virus or through vaccination, the game changes. Versions of the virus with mutations that get around the population’s immunity are more likely to spread, and can then develop into new strains.

Editorial Disclaimer: information published during the 2020 COVID-19 pandemic may be updated frequently to reflect the dynamic nature of current understanding.

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