COVID Variant BA.2.86: All About Its Symptoms and Spread – TODAY

As federal heath officials urge Americans to get the new COVID-19 booster this fall, new variants of the virus continue to spread in the United States, stoking fears about a winter surge.

In August, a highly mutated COVID-19 variant called BA.2.86, or "Pirola," made headlines after it was detected in humans and wastewater samples in the U.S. and several other countries.

Health officials have been closely monitoring the new variant as it spreads. Initially, Pirola set off alarm bells for some scientists due to its large number of mutations, which differentiate it from previous omicron subvariants that have gained dominance since 2021.

According to the U.S. Centers for Disease Control and Prevention, BA.2.86 is notable because it has multiple genetic differences, and it was detected in several locations in a short amount of time, the agency said in an update on BA.2.86 on Aug. 30.

In a risk assessment, the CDC said it BA.2.86 may be more capable of bypassing existing immunity from COVID-19 vaccines or prior infection, but there is no evidence it causes more severe illness.

Less than 1,000 cases of BA.2.86 have been reported worldwide so far, and the variant did not appear to drive the late summer surge in cases and hospitalizations in the U.S., experts told NBC News.

However, concerns about Pirolas ability to cause breakthrough infections have resurfaced as health officials roll out new COVID-19 vaccines, which target the omicron XBB.1.5 variant.

Moderna and Pfizer have said their updated COVID-19 vaccines appear to generate a strong immune response against BA.2.86, and experts anticipate the shots will provide good protection against newer strains circulating this fall, TODAY.com previously reported.

Additionally, data from lab studies suggest the Pirola variant may be less contagious and immune-evasive than previously feared, NBC News reported.

It's unclear whether BA.2.86 will cause a surge in infections this winter, but there's no reason to panic, experts say.

Here's what experts know so far about BA.2.86, aka Pirola, the symptoms it's causing, its ability to spread and how it could impact COVID vaccine vaccines this fall.

BA.2.86, which health experts dubbed Pirola on social media, was first detected in late July. It appears to have descended from the omicron BA.2 sublineage, which caused surges of the virus in early 2022, Andrew Pekosz, Ph.D., virologist at Johns Hopkins University, tells TODAY.com.

The critical thing about this variant (BA.2.86) is that it has a whole host of mutations compared to some of the omicron variants that emerged about two years ago, says Pekosz.

Early data show BA.2.86 has 34 more mutations in its spike protein than BA.2, which drove a COVID surge in 2022, and an additional 36 more mutations than XBB.1, which rapidly took over the U.S. in early 2023, according to an Aug. 24 paper in The BMJ.

The mutations or changes in the virus sequence can affect how contagious a virus is, how well it responds to treatment and how severely it affects people, per the CDC.

It represents a highly mutated form of SARS-CoV-2, says Pekosz in other words, BA.2.86 looks very different from the prevailing omicron XBB subvariants circulating.

Right now, "there's no data on symptoms associated with infection because the case numbers are just too small," Pekosz says.

In its risk assessment of BA.2.86, the CDC said "at this point, there is no evidence that this variant is causing more severe illness," but this may change as additional scientific data comes in.

Common symptoms of other COVID-19 variants and subvariants include:

Based on what the CDC knows now about BA.2.86, existing tests and medications used to treat COVID-19 "appear to be effective with this variant," the agency said.

The World Health Organization first classified BA.2.86 as a variant under monitoring on Aug. 17. Since then, BA.2.86 variant has been linked to over 640 cases in 30 countries, per the global virus database GISAID.

The countries reporting the highest number of cases are the United Kingdom, United States, Sweden, Denmark, Spain, Canada, South Africa, and France. BA.2.86 has also been detected in wastewater samples in additional countries, the CDC said.

So far, there have been 65 cases reported in at least 15 in the U.S. in either people or wastewater, per GISAID and the CDC.

The variant is probably spreading much more broadly than weve detected so far, says Pekosz, adding that a lack of testing and sequencing is likely causing a delay in reporting.

Right now, the EG.5 or Eris subvariant, a descendant of the omicron XBB sublineage, accounts for the largest proportion, 23.6%, of COVID-19 infections in the U.S., according to the latest estimates from the CDC.

After EG.5, the next most common subvariant circulating in the U.S. is another omicron XBB descendant, HV.1, followed by the closely related FL.1.5.1 or "Fornax," and offshoots of the XBB.1.16 orArcturus variant, per CDC data as of Oct. 13.

Globally, EG.5 and XBB.1.16 are the most prevalent COVID-19 strains, according to the latest WHO COVID-19 situation report.

Right now, it's too early to tell whether BA.2.86 is more transmissible than other variants, says Pekosz. "It's impossible to gauge anything about transmissibility or disease severity from that (small number of cases)," he adds.

However, based on what we know about the genetic sequence of BA.2.86 and the mutations in its spike protein, the variant will likely be able to escape preexisting immunity to COVID-19, Pekosz says.

The CDC echoed this in its BA.2.86 risk assessment, which stated that the variant could be more capable of causing infection in people who previously had COVID-19 or got vaccinated.

"Most of the mutations that we find in the spike protein are probably going to affect the ability of antibodies to bind and neutralize the virus," Pekosz adds.

In other words, BA.2.86 could escape not only immunity from vaccination or prior infection up until this point, but also vaccine-induced immunity from the coming fall vaccine, Pekosz adds.

"That's why this variant is very concerning to us from a scientific standpoint," he adds. "We need more sequences and cases to understand the variant's transmissibility."

According to the CDC, laboratories are currently researching the antibody neutralization of BA.2.86 to better understand how the immune system may interact with the virus.

We really dont know if BA.2.86 will lead to increased numbers of cases, Pekosz says. "The sequence cant tell us how much disease the virus will cause, nor can it tell us how well its spreading," says Pekosz. Only time and more data will tell.

However, the BA.2.86 does not appear to be behind the late summer COVID surge around the country, which was likely driven by a combination of EG.5 and otheromicron variantscirculating.

Nationwide, COVID hospitalizations appear to be trending downwards. In the last two weeks, average daily hospitalizations in the U.S. decreased by 9.5%, according to anNBC News analysis.

However, CDC director Dr. Mandy Cohen said that cases are expected to increase this fall and winter, TODAY.com previously reported.

In September, federal health officials approved a new COVID-19 booster to roll out this fall. The updated vaccines for 2023-2024, which target the omicron XBB.1.5 variant, are recommended by the CDC for everyone ages 6 months and older.

In recent weeks, millions of doses have arrived at pharmacies and doctors offices around the country. The CDC encourages everyone eligible to get at least one dose of the updated vaccine to protect against serious outcomes of COVID-19 this fall and winter.

Right now, there are three vaccine options authorized by the FDA. These include two mRNA vaccines from drugmakers Moderna and Pfizer, which are recommended for everyone ages 6 months and older, as well as a protein-based shot from Novavax, which is approved for everyone ages 12 and older.

Manufacturers have reformulated the vaccines to protect against the omicron XBB.1.5 subvariant, which was the dominant strain circulating for most of 2023 but has since been overtaken by Eris, Fornax, and Arcturus.

Although the new boosters do not include BA.2.86, recent data has suggested that the updated vaccines may provide more protection than initially thought against Pirola.

Moderna said that clinical trial data confirmed its new vaccine "showed an 8.7 to 11-fold increase in neutralizing antibodies against circulating variants, including BA.2.86."

The boosters will be well-matched to the other strains currently making people sick, says Pekosz and they will still be effective at reducing severe disease and hospitalization, per the CDC so it's important for people to stay up to date with COVID vaccines.

The CDC is encouraging everyone eligible get at least one dose of the updated COVID-19 vaccine, especially those at higher risk, which includes people over the age of 65, those with underlying health conditions and the immunocompromised.

In addition to vaccination, people can protect themselves against COVID-19 by taking precautions such as wearing a mask, practicing social distancing, avoiding sick people and maintaining good hand hygiene.

Caroline Kee is a health reporter at TODAY based in New York City.

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COVID Variant BA.2.86: All About Its Symptoms and Spread - TODAY