An Easy Way To Understand Variants — Using Puzzle Pieces | NPR

Michaeleen Doucleff (00:00):

First, we were worried about the Corona virus. Now we’re worrying about Corona virus variants, and there are a lot of them spreading around the world. Some are more contagious and possibly more deadly. What the heck is going on with all these variants? To answer that question, let’s go back in time to January, 2020, when we were all blissfully going about our lives.

Michaeleen Doucleff (00:21):

Back then the coronavirus looked a bit like this. Well, not really, but if it was made of puzzle pieces, it would look like this. The virus is basically a ball with little spikes on the surface, poking out. Now our cells aren’t stupid. They don’t let just any virus inside willy nilly. The cell goes to great links to keep intruders out. For anything to enter, the intruder must figure out a way for its spike to bind to another spike on the cell surface. You can think of this binding as a secret handshake and the handshake tells the cell, hey, cell it’s okay. You can let him inside. That’s exactly what SARS COV2 has done. Sometime in 2019, probably in China, it figured out a way to interact with a specific spike in the surface of human cells. This interaction wasn’t perfect, but the binding was good enough to trick the cells receptor.

Michaeleen Doucleff (01:15):

And the receptor mistakenly told the cell, Hey, cell this guy is friendly. We can let him inside. Ooh, big mistake.

Michaeleen Doucleff (01:24):

Once the virus was inside, it made a bunch of copies of itself busted the cell wide open and released new virus particles inside the blood, which went out and found another cell to infect. During this time, the body isn’t standing by idly letting this attack occur. Oh no. The immune system is already preparing a counter attack. It’s manufacturing antibodies. Some of those antibodies act like little caps that stick to the ends of the viruses spike like this. Once capped the spikes can no longer stick to the cells, receptor the infection can’t move forward and the body wins. That’s pretty much how Corona virus infections played out for About nine months or so then in September, 2020, The virus got crafty and the pandemic began a new phase.

Michaeleen Doucleff (02:14):

Every time the virus copies itself inside a cell, it has the chance of mutating or changing its gene slightly. Most of the mutations are actually harmful to the virus. They disable it. So these mutations disappear, but every so often the virus happens upon a set of mutations that actually help the virus. In the case of the new variants, the mutations changed the shape of the viruses spike in a particular way so that it fits better to the ACE two receptor. So this spike can bind more tightly to the cell or more quickly. The result? A person cells get infected more easily or more of their cells let the virus inside. We didn’t really know why, but that person may make more virus particles inside their nose and upper respiratory system. So when they sneeze, cough, or just talk, they expel more virus and that’s likely why the new variant is more contagious.

Michaeleen Doucleff (03:09):

But wait, what about those antibodies? What about the little caps on the spike? Aren’t they coming to save us again? Well, yes and no.

Michaeleen Doucleff (03:19):

Turns out some of the mutations changed the shape of the viruses spike in a way that’s double trouble for the cell. Some antibodies no longer fit well to the end of the spike. So they can’t form the little caps that blocked viral infection. As scientists say, these mutations help the virus evade the immune system. So a person who is infected with the older version of the virus may not be protected as well against these new variants. And that person may be more likely to be reinfected.

Michaeleen Doucleff (03:48):

Now antibodies are a diverse crew. They come in a lot of different shapes, Which combined to a lot of different parts of the virus. All these other antibodies can help take down the virus and reduce infections. So even though some antibodies become less helpful, others hopefully will take up the slack and still get the job done, or at least stall the infection long enough until the body can make new antibodies that fit perfectly on the mutated spike.