The Science of Why Virus Mutations Matter

A new paper from the Scripps Institute gets into the nuts and bolts of how virus mutations change the effectiveness of both prior infection and vaccines.

To review the basics: the coronavirus is coated with spikes that it uses to latch onto receptors in specific cells in your body. For this explanation, we’ll call the cells the virus attacks in your body “target cells.” Once the virus attaches to a target cell, it invades the cell, reproduces in large numbers, and eventually causes the cell to disintegrate releasing the progeny to attack more cells. This release from a dead cell is shown in the NIH image below.

The points at which the virus attaches to a target cell or an antibody are called receptor binding sites (RBS).

The spikes in the coronavirus are made up of chains of amino acids which naturally fold into specific shapes. In dissecting the RBS locations on the spikes, scientists have identified the amino acids and labeled their positions in the spikes. They have identified three positions along the spike that are involved in connecting with cells the virus is attacking, as well as in connecting with antibodies trying to defend against the attack. By occupying these attachment points, the antibody prevents the virus from being able to attach to and attack a target cell in your body.

Antibodies are naturally generated by your body to fight any infection. They may also be stimulated by a vaccine.

In the South African and Brazilian variants, scientists have identified mutations that have changed the amino acids in the spikes at three locations — positions 417, 484 and 501. The changes in the amino acids changes the shape and function of the spike. The changes in 417 and 484 reduce the ability of antibodies to bond with the virus. These changes also reduce the ability of the virus to bond with target cells it is trying to infect. However, the change in position 501 improves the ability to bond with target cells.

The net result is that the mutated virus is less likely to bond with an antibody and still fully capable of attacking target cells.

The good news is that the research team identified other antibodies that the body generates that could neutralize the virus even with these mutations. That may mean changing the current vaccines to stimulate release of these other defenses.

Bottom line: As we learn about the virus, we are finding better ways to fight against it. That’s as it should be. There’s always a learning curve when dealing with something new.

So get the vaccine that we have now, and get the new one when it comes out. Because the long-term damage the virus can do to you without your knowing is way beyond grotesque.



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