Is omicron subvariant BA.5 the ‘worst’ version of COVID yet? Here’s what we know

Julia Marnin
Ted S. Warren/AP

Yes, another omicron subvariant — BA.5 — is now dominant among coronavirus cases reported in the U.S.

But is BA.5 the “worst” version of COVID-19 to date? One scientist, Dr. Eric Topol, founder and director of Scripps Research Translational Institute, described it as such in a report about the subvariant’s “takeover” in late June.

“This version of the virus has caused a lot of trouble, more than other Omicron subvariants,” Topol wrote in an updated report on BA.5 on July 10.

The subvariant makes up more than 53% of COVID-19 cases in the country as of July 2, according to Centers for Disease Control and Prevention data estimates. It has surpassed other omicron subvariants, including “stealth omicron,” or BA.2, which ruled cases in the spring.

Here’s what we know so far about BA.5.

BA.5’s ‘immune escape’

The subvariant was characterized as “a whole different animal” by UC Davis Health because it is “most easily transmissible” and has a capacity to “evade previous immunity from COVID infection and vaccination.”

It was found that BA.5 and another newer omicron subvariant, BA.4, were four times more resistant to antibody protection offered by COVID-19 vaccines compared to BA.2, according to research published July 5 in the journal Nature.

While BA.5 makes up more than half of cases in the U.S., BA.4 was estimated to make up roughly 16% as of July 2, CDC data shows.

In Topol’s report, he wrote that BA.5 and BA.4 are the “most immune-evasive variants,” based on recent studies, but BA.5 is the most transmissible of the omicron lineage.

He said BA.5 “takes immune escape, already extensive, to the next level, and, as a function of that, enhanced transmissibility, well beyond Omicron (BA.1) and other Omicron family variants that we’ve seen (including BA.1.1, BA.2, BA.2.12.1, and BA.4).”

This was noted in a preprint study that found BA.5 has an “increased transmission potential in the community,” according to the work published July 10 to MedRxiv involving researchers from the Kirby Institute in Australia.

Dr. Nicole Van Groningen, of Cedars-Sinai Medical Center in Los Angeles, told KTLA that BA.5 “tends to have this capacity for reinfection” and this creates concerns about “increasing cases this summer.”

Likely BA.5 and BA.4 reinfections after four weeks of an initial COVID-19 infection have been observed by Western Australia chief health officer Dr. Andrew Robertson, Business Insider reported.

What are BA.5 symptoms?

When it comes to symptoms of a BA.5 infection, they are not notably different compared to omicron and its other subvariants, The New York Times reported.

Some symptoms of omicron, according to the CDC, include:

  • Cough

  • Fever

  • Fatigue

  • Breathing troubles

  • Runny nose

  • Congestion

  • Sore throat

  • Gastrointestinal issues

  • Body aches

  • headache

Dr. Peter Chin-Hong, of the University of California, San Francisco, told The New York Times that those infected with BA.5 or BA.4 are “less likely to lose their senses of taste and smell, or to experience shortness of breath, as compared with those infected with Delta or other variants of the coronavirus.”

Because BA.5 is a newer omicron subvariant, “there is more to learn” about it, Yale Medicine reports.

Is BA.5 more severe?

It is not yet known whether BA.5, or BA.4, may cause a more severe COVID-19 infection compared to earlier omicron versions, according to the European CDC.

Early research from South Africa, where the original omicron strain was first recorded, showed there has not been a spike in deaths due to BA.5, Yale Medicine said.

A preprint study published May 26 in BioRxiv found that BA.5 and BA.4 spread more rapidly in human lung cells compared to BA.2. Additionally, it found that the newer subvariants were more severe in infected hamsters compared to BA.2.

“There’s clearly more room for the virus to evolve, get more fit, gain advantages as an immune escape artist and more efficiently infect cells,” Topol wrote in his July 10 report.

The spread of BA.5 comes as the majority of the U.S. lives in a location where COVID-19 community spread levels are considered medium or high as of July 11, according to the CDC. Roughly 41% of the country lives where COVID-19 levels are considered low.

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