As health officials prepare for another coronavirus variant, Lambda, to spread, one researcher says she believes the mutation will "run into a problem" in becoming the dominant strain in the U.S.
Dr. Anna Durbin, a professor in the Department of International Health at the Johns Hopkins Bloomberg School of Public Health, told Newsweek that the Lambda variant "is going to run into a problem here in the U.S. and that is the Delta variant."
"These viruses are all competing with each other for advantage to be the one that survives," Durbin said. "We know that the Lambda variant has some of the same mutations as the Delta variant that we think [will] allow it to be more transmissible, so it would be difficult to outcompete the Delta variant."
While the Lambda variant, which was first detected in Peru and has predominately spread in South America, only makes up 0.17 percent of the variant cases in the U.S., the Delta variant is responsible for more than 93 percent of circulating U.S. cases.
Durbin thinks that because the Delta variant has become so prevalent in the U.S., Lambda won't be able to outcompete the highly transmissible strain currently surging across the country.
"It's survival of the fittest," she said. "You have these viruses that replicate and they get mutations. The one that can replicate for the highest titer or be transmitted better is the one that's going to survive because that one is going to spread more easily and the other variants are going to sort of just die out."
It is the same reason why the Delta variant is currently the dominant strain.
The Alpha variant—which was first identified in the U.K. and has been shown to increase transmission by 50 percent compared to the original virus—swept the U.S. during the spring and became the most common strain by April.
But the arrival of the Delta variant in March kicked Alpha out of first place, steeply rising to become the most dominant strain of the coronavirus.
Delta, first identified in India, is not only more transmissible but has been found to be more resistant against vaccines, which explains why there have been a higher number of breakthrough cases in vaccinated people amid the latest surge.
With the Delta variant surging, Durbin explained that other variants, like Gamma, were unable to take hold.
She said that because the Delta variant got a foothold before the Lambda variant did in the U.S., she doesn't see Lambda being able to come in and out-compete Delta—just as the Delta variant would be unable to sweep South America since Lambda claimed territory there first.
Durbin said that while she doesn't believe the Lambda variant could overtake the Delta variant in its current state, there is a possibility that Lambda could continue to mutate and become more powerful than Delta.
"Could there be other mutations that occur to make it more transmissible than Delta? That certainly is a possibility," Durbin said on Thursday. "At this point, in South America, the Lambda variant is competing against the Alpha variant or the original Wuhan strain and it certainly has a competitive advantage, but I think it loses that competitive advantage when it goes up against the Delta variant."
She said the only way to get to a place where stronger variants wouldn't pose a public health threat is if enough people are vaccinated globally.
"As long as you have this virus circulating in people who are not immune, mutations will occur," she said. "We have to vaccinate the world if we want to stop this virus from mutating and that is a really, really difficult task to do, but it's something that we have to put all our effort into doing."
Given the effectiveness of the vaccines against the Delta variant, Durbin said vaccinated individuals should also be protected from the Lambda variant.
"[People] should certainly take precautions but for the most part, yes, if you're vaccinated, you should feel confident that you're protected," she said.
She stressed that while vaccinated people could still get sick, the vaccines are doing their jobs at limiting the severity of the virus and stopping people from requiring hospitalization.
"Unfortunately, because these vaccines have been so effective, our expectations haven't really been realistic," Durbin said. "It's unrealistic to think that these vaccines are going to prevent infection. That's not what vaccines do. That's not what natural infection does. You're not protected for the rest of your life from being reinfected but you're protected from getting severely ill."
Although the U.S. has administered at least one dose of a coronavirus vaccine to 58 percent of its total population and has fully vaccinated nearly 50 percent of the population, less than 30 percent of the world's population has received at least one dose. Globally, only 15 percent have been fully vaccinated.
