Where Do COVID Variants Come From, Anyway?

Variants of the virus that causes COVID-19 didn’t really make news until this year, despite the virus spreading around the globe all through 2020. There’s some misinformation out there blaming the vaccine itself for these variants, but that seems to be based on a misunderstanding. Let’s explore the facts.

The truth: More infections = more variants

There’s a saying in biology that “nothing makes sense except in light of evolution.” And that’s definitely true here. As anything reproduces — whether viruses or human beings — some of the individuals will be a little different from their parents. DNA isn’t copied exactly perfectly, or in the case of some viruses, their RNA isn’t copied perfectly. Those changes are called mutations.

“In fact, the high error rate in RNA viruses is thought to be part of their evolutionary strategy,” virologist Matt Koci told Applied Ecology News. “If you create [thousands] of offspring, many with random mutations, it increases the chances that one of them will be better suited for survival. Many of those mutations will make things worse for the virus and may even render them inert.”

In other words, every time the virus reproduces, there’s a teeny tiny chance it might come up with a version that will be able to spread more rapidly. The more people are infected, the greater the chance that a dangerous variant could emerge.

In that AEN interview, which was published in March of 2021, the reporter asked how one would encourage viral evolution, if you wanted to increase the chances of a harmful variant emerging. “I’d do what we’re doing in the U.S.,” Koci said. “Allow the virus to run more or less unchecked.”

The myth: Vaccines are to blame

Vaccines are an important tool in preventing viral evolution. The fewer people that get infected, the fewer opportunities the virus has to come up with new variants. The same can be said for other control measures, like masks, social distancing, and holding meetings remotely.

But there’s a myth that has taken hold among people who are suspicious of vaccines: They say that vaccines encourage variants. This theory likely rose to popularity from a Joe Rogan episode that cited a 2015 study on viral evolution.

The study didn’t involve COVID-19, nor did it involve humans. It was about a chicken vaccine for something called Marek’s disease, and showed that a “leaky” vaccine (one that allows a lot of breakthrough infections) could affect viral evolution.

But the study’s author, Andrew Read, told Forbes that his study does not support Rogan’s take that COVID vaccines are a bad idea. Read and his family are vaccinated. He told Forbes:

“Evolution [of the virus that causes COVID-19], at the moment, is all happening in the unvaccinated. That’s where the majority of cases are. That’s the majority of transmission. Every time a virus replicates, it can mutate. So the evolution is, right now, occurring in the body of people who are not vaccinated. Rogan is completely wrong trying to deduce anything else.”

Delta, the variant that is so transmissible it is now the dominant strain of COVID worldwide, emerged in India where vaccination rates were very low. Current evidence tells us that vaccines deny the coronavirus opportunities to mutate; they do not encourage mutation. So the most important way to fight this pandemic is still to get vaccinated if you can.