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There are several COVID-19 variants that scientists say are gaining strength around the world, including in the United States. KENA BETANCUR/AFP via Getty Images
  • The delta variant is poised to become the dominant COVID-19 strain in the United States, but there are concerns other mutations are gaining strength.
  • Among them are the delta plus, gamma, and epsilon variants.
  • Experts say unvaccinated people provide the novel coronavirus with a place to spread and mutate.

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Los Angeles County health officials are so worried about the rapid spread of the COVID-19 delta variant, they’re urging residents to put their masks back on when indoors at public places, whether they are vaccinated or not.

That recommendation comes as some countries return to lockdowns and put public health restrictions back in place.

The delta variant, first identified in India, is on track to become the most dominant variant worldwide. The World Health Organization (WHO) says it has been detected in 92 countries.

“It is so highly contagious,” said Dr. William Schaffner, a professor of medicine in the Division of Infectious Diseases at the Vanderbilt University School of Medicine in Tennessee.

“It’s already causing about a quarter of all U.S. cases and is on the climb,” he told Healthline. “It’s anticipated that within a month, it will also become the most dominant strain in the United States.”

Researchers are also monitoring a mutation of the delta variant called delta plus, recently identified by scientists in India.

“Delta plus is just shorthand for delta with one mutation,” said Jeremy Kamil, PhD, a virologist and associate professor of microbiology and immunology at Louisiana State University.

“It makes it easier for the virus to get past the antibodies,” he told Healthline.

Scientists say there is a lot more to learn about the delta plus strain. There are some 200 known cases in about a dozen countries.

“So far, it doesn’t have any major implications, certainly nothing close to the delta itself,” said Schaffner.

Then there’s the gamma or P.1 variant, originally detected in Brazil. It’s on the rise in the Pacific Northwest.

“It’s very effectively outcompeting the alpha and delta variants, and the rest of the country isn’t seeing this,” Dr. Scott Lindquist, Washington state’s acting health officer, told the Spokesman-Review. “Many of our counties here are seeing the gamma variant. It’s got the highest hospitalization rate of all of our variants.”

The U.S. Centers for Disease Control and Prevention (CDC) reports that scientists are also tracking these other variants in the United States.

  • alpha: first detected in the United Kingdom
  • beta: initially emerged in South Africa
  • epsilon: two variants that were first identified in California

Scientists say areas with large numbers of people who are not vaccinated are more vulnerable and provide an opportunity for mutations to occur.

“Every time the virus infects someone that’s not vaccinated, it has a chance to evolve and change and tinker with its recipe,” Kamli said. “And when you let it move around in an unvaccinated population, that’s how you get new variants.

“In places like California, the unvaccinated end up being protected by the vaccinated to a large degree,” he explained. “That’s how herd immunity classically is thought to work.”

Recent data from Los Angeles County shows the impact the variants have on those residents who are not vaccinated.

Health officials say that the delta mutation accounts for nearly half of all variants identified in the county. In the number of people hospitalized with COVID-19, more than 98 percent were unvaccinated.

Among the people who died from the disease, more than 99 percent had not received a vaccine.

Experts say those numbers may be a cautionary tale.

“That’s why we’re worried. Our case rates had gone down precipitously. Now, they’ve plateaued,” Schaffner said. “That’s because this delta variant is spreading among middle-aged and younger adults. And it’s spreading in those parts of the country that are unvaccinated.

“Unvaccinated people are potential mutation factories,” he added.