How does the SARS-CoV-2 virus mutate? How have vaccines helped overcome challenges to controlling the virus? Michigan Medicine infectious disease specialist Adam Lauring, MD, PhD, joined Michigan Minds for an episode of its special series on COVID-19 to discuss RNA viruses, mutation rates, and mitigation measures.
Lauring is a physician-scientist, so some of his time is spent caring for patients and the rest of it is spent running a research lab composed of students, postdoctoral fellows, and research technicians who are studying how RNA viruses, including SARS-CoV-2, evolve. He says that COVID-19 has caused unique challenges to control.
“We’re always focused on how viruses change over time and how that can affect vaccines or other measures of control. I think we’re seeing that play out now with COVID. The other thing we’ve seen over the last 18 months is that there are so many challenges to controlling a completely new virus causing a pandemic,” Lauring says.
“The other challenge has been how our lack of control in general, both in the US and around the world, has contributed to the virus’ rapid evolution. Every infected person is a chance for the virus to try out new mutations and innovate, and that’s something that has played out in ways that I don’t think many of us anticipated a year and a half ago.”
Lauring emphasizes that the vaccinations against COVID-19 are impressive and “amazingly effective,” , and have the potential to solve some of the challenges communities are facing with infection transmission.
“If we could deploy the vaccine to enough people, then those issues become less of a problem because you don’t need to worry about tracking every single person and whether they’re infected or transmitting. Of course, all of this could have an evolutionary benefit. If you vaccinate enough people, there’ll be fewer infected people. That means fewer changes for the virus to make and long-term outlook and trajectory looks better.”
Lauring explains that the epidemiology of SARS-CoV-2 is difficult to manage because of the way it mutates. Each infected person harbors millions of viruses and each of those viruses make new mutational steps all the time, meaning there are ample opportunities for the virus to take a new direction — not because the evolution has changed, but because of the epidemiology of what is taking place.
“When describing the mutational process, I often liken viruses to people playing slot machines. Generally, people lose, and so the virus loses by making mutations. But if there are enough people playing the slots for long enough, someone eventually hits a jackpot and so rare events happen if the numbers are picking up,” Lauring says.
With humans as hosts for the virus, the virus has potential to improve — which is wwhat we have been seeing over the past six to nine months, he says. There isn’t much that people can do to control how a virus mutates, but by reducing the number of people infected, it reduces the opportunities for the virus to replicate itself.
“We can reduce the number of people infected through masks, physical distancing, and vaccines, and that effectively reduces opportunities for the virus to replicate, to copy itself, and therefore, to make new mutations.”
He acknowledges that it was discouraging to see that transmissions didn’t significantly decrease over the summer as anticipated but notes that we have agency to alter the course of the epidemic.
“I think it’s easy to look at the news about COVID and be discouraged. This is understandable, as we thought we were emerging from this mess as we moved from spring into summer,” he says. “We have effective tools. We’ve learned a tremendous amount about the virus in a short amount of time, and vaccines remain quite effective at preventing serious illness, which is what the vaccines were designed to do.”
He adds that vaccinations are the most important thing for communities right now, and encourages those who haven’t been vaccinated to talk with their health care provider.
