'Superpower Is Reinfection': Worrisome Omicron Subvariant BA.5 Causes New Concerns

ACROSS AMERICA — The new coronavirus omicron subvariant BA.5 is responsible for more than half of the country’s new COVID-19 cases, according to the most recent data from the Centers for Disease Control and Prevention.

A second subvariant, known as BA.4, makes up more than 17 percent of cases, according to the agency’s data tracker.

The pandemic isn’t over, though new cases are less than 25 percent of what they were in January. Still, the new subvariants are worrisome.

Below are five things to know about BA.5 and BA.4:

Are Symptoms Different?

Generally, no.

BA.4 and BA.5 symptoms are similar to earlier omicron variants and include a cough, runny nose, sore throat, fatigue, headaches and muscle pains. But people infected with the new variants are less likely than those sickened by earlier versions of omicron to experience shortness of breath or lose their senses of taste and smell, Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco, told The New York Times.

But there’s more to be learned about the two new subvariants.

“There also have been some concerning findings in laboratory studies, which found that BA.4 and BA.5 were better able to infect lung cells than the earlier BA.2 subvariant of Omicron,” Los Angeles Public Health Director Barbara Ferrer told the Los Angeles Times.

Are BA.4 And BA.5 More Contagious?

Both are considered highly contagious — in general, more so than earlier versions of omicron COVID-19.

David Montefiori, a professor at Duke University Medical Center’s Human Vaccine Institute, told NBC News the new variants are “taking over, so clearly they’re more contagious than earlier variants of omicron.”

BA.5 is of particular concern, Dr. Eric Topol, the director of the Scripps Research Translational Institute in La Jolla, California, recently wrote on a blog post, calling it the “worst version of the virus” to date.

With both BA.4 and BA.5, the “superpower is reinfection,” Chin-Hong, the UC San Francisco infectious diseases expert, told the Los Angeles Times.

Ferrer told The LA Times “there’s strong evidence” that both BA.4 and BA.5 “can spread even faster than other subvariants.”

Are Vaccines Effective Against BA.4 And BA.5?

They’re not ineffective.

But one of the reasons BA.4 and BA.5 have become the dominant versions of omicron is that they’re more resistant to antibodies, either from previous infections or vaccines, than other versions of omicron and delta COVID-19.

“At this stage now, I think all these variants actually are roughly equally transmissible, so there’s not a huge difference,” Francois Balloux, the director of the University College London Genetics Institute, told NBC. “It’s just some are slightly better at infecting people who have been vaccinated or infected by previous variants.”

One study found the new variants about three times less sensitive to antibodies. Another study suggested BA.4 and BA.5 are four times more resistant to antibodies from vaccines than BA.2, which replaced the omicron variant as the dominant version of COVID-19 in April.

“These novel subvariants carrying additional mutations in their spike proteins raise concerns that they may further evade neutralizing antibodies,” further compromising the efficacy of vaccines and therapeutics, researchers said in a study published Tuesday in the journal Nature.

Will Boosters Target Subvariant?

The Food and Drug Administration last week recommended that vaccine manufacturers redesign COVID-19 booster shots this fall to specifically target the new subvariants.

“As we move into the fall and winter, it is critical that we have safe and effective vaccine boosters that can provide protection against circulating and emerging variants to prevent the most severe consequences of COVID-19,” the agency’s advisory committee said in a notice on the FDA website announcing its June 28 decision.

What’s Next For 'Slippery Virus'?

One constant of the coronavirus is its ability to change.

“We didn’t really appreciate how slippery this virus would be,” said Paul Bieniasz, a professor at Rockefeller University, telling TIME he expects the virus to continue to further evolve to escape the immune system’s defenses and vaccines.

Shishi Luo, the associate director of bioinformatics and infectious diseases at Helix, which partners with the CDC to monitor emerging COVID variants, told TIME the virus’ ability to reinvent itself shouldn’t be taken lightly.

“We can expect to be reinfected. And every time we’re infected, it’s at best a hassle. And at worst, it can lead to debilitating symptoms,” Luo told TIME, pointing to the risk of what’s known as Long COVID.

Robert Watcher, who chairs the Department of Medicine at the University of California, San Francisco, wrote on Twitter the behavior of BA.5 “will determine our fate for the next few months, until it either burns itself out by infecting so many people or is replaced by a variant that’s even better at infecting people.”

“Neither is a joyful scenario,” he wrote.