Infectious disease experts around the world are keeping a close eye on the newest COVID-19 subvariants with strange names like BA.2.75, BA.2.75.2, BA.4.6 and BF.7.

Should you be concerned about these descendants of the original virus that sparked the pandemic?

To help you learn more, we consulted with UCHealth infectious disease expert, Dr. Michelle Barron.

Like a weather forecaster, Barron has been studying the newest subvariants. She’s keeping them on her radar but doesn’t want people to worry yet.

“We’re seeing them in the U.S., but still in very low numbers,” said Barron, who is UCHealth’s senior medical director of infection prevention and control and one of the top infectious disease experts in Colorado.

“They’re like tropical storms. They’re way out in the ocean right now. We’re aware of what they have the potential to do, but they may never gain enough strength to hit land or even become a named storm,” said Barron, who is also a professor at the University of Colorado School of Medicine on the Anschutz Medical Campus.

The current crop of subvariants includes BA.2.75, BA.2.75.2, BA.4.6 and BF.7.

All of the newest subvariants are descendants of the omicron variant. Omicron is the highly transmissible variant that sprang on the scene early in 2022 and has been spreading widely ever since. The most recent omicron variants that most people have heard of include BA.4 and BA.5.

Globally, through mid-September (the most recent period for which data are available), the omicron BA.5 variant was still causing the majority of infections, accounting for about 80% of cases around the world, Barron said.

BA.2.75 and BA.2.75.2 first emerged in India and are now spreading in the United Kingdom.

So far, the newest subvariants are causing about 2-to-5% of cases in the U.S., Barron said.

Experts don’t know exactly how protective the new booster shot (and previous vaccines) will be.

But they are strongly advising people to get their primary vaccines and a booster shot as soon as they’re eligible.

“The booster gives you an extra layer of protection against whatever is coming next. Will it be 100% effective? Probably not. But, it’s definitely more than zero,” Barron said.

Regardless of exactly how protective the new booster shot proves to be against the newest subvariants, vaccines and booster doses have helped reduce the severity of illness and have prevented deaths from COVID-19.

Vaccine makers created a booster dose with a new recipe. It became available in the U.S. starting in early September. This new booster dose specifically fights omicron variants including BA. 4 and BA.5.

“The newest subvariants are related to BA.4 and BA.5, but we still don’t know how well this vaccine works against them,” Barron said.

Early studies to measure the booster efficacy on new subvariants are not definitive, Barron said.

One researcher found that the BA.2.75.2 subvariant may be able to evade vaccines and COVID-19 treatments.

But a different study found that vaccines worked well against the subvariant.

It’s too early to know for sure.

“We don’t know yet how well the newest boosters will hold up against new omicron subvariants,” Barron said.

That’s a tricky question to answer, Barron said.

Some past variants and subvariants seemed like they might cause problems, then didn’t prove to be threatening. On the other hand, new versions of the virus have the potential to suddenly take over. That’s what happened when the delta variant came on the scene late in 2021. Researchers in South Africa first discovered the delta variant and it very quickly exploded around the world. That could happen with these new subvariants. Or, they could fizzle out, Barron said.

Viruses evolve so they can continue to stay alive and spread. The best way to do that is to change over time. That’s how variants and subvariants develop.

Barron gets it that people are tired of worrying about viruses. It’s her job to watch for potential threats. While it’s vital to be aware of potential storms on the horizon, she’s urging people not to be too concerned.

“We all have this trauma from the beginning of the pandemic, and we were at DEFCON 10. We don’t have to go back there again, but we’re not at zero either. We just need to pay attention,” Barron said.

“It’s a nuisance to think about the newest subvariants, but just as we all watch the weather, we should be aware of what’s out there, so we can be prepared,” she said.

There have been some early reports that the BF.7 subvariant could be both highly infectious and could make people really sick.

“It has some novel sequences that make it more transmissible. The other concern is the potential for more severity. If it’s like the love child between delta and omicron (variants), that would be bad. But all of our information is still very premature,” Barron said.

The best way to protect yourself is the same as it has been throughout the pandemic. If you are immunocompromised or you live with or spend time with someone who is, be careful about spending time in crowded, indoor settings, Barron said.

The same measures that have helped drive down infections throughout the pandemic still work. They include:

Masks are highly effective and are still required in health care settings.

“It’s not like we’re trying to put you back into March of 2020, but there’s still tremendous value (for some people),” Barron said.

“Every day, I put on my seat belt because it’s the law. Do I necessarily like it? No. Does it keep me safer if I get in an accident? Of course.

“We have tools to make things safer,” Barron said. “People who come into hospitals generally need to be here. Whether they have to have cancer treatments or have diabetes and need medications, it’s our job as health care providers to protect them.”

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