New COVID variant BA.2.86 spreading in the U.S. in August 2023. Here are key facts experts want you to know.

Health authorities and scientists say they are now racing to study BA.2.86, a new strain of the virus that causes COVID-19, after the highly mutated variant was spotted spreading in multiple countries around the world and at least three different U.S. states.

For now, officials say they remain well-equipped to deal with the strain if it continues to spread. Early assessments suggest current treatments and tests, as well as upcoming vaccines to be rolled out next month, will not be rendered useless by BA.2.86. 

But a number of questions remain about the variant, nicknamed "Pirola" on social media, whose mutations could amount to an evolutionary jump on par with the emergence of the Omicron variant in 2021. 

Here's the latest on what we know about the strain.

Is there a new COVID variant? 

The Centers for Disease Control and Prevention and World Health Organization say they have been closely tracking the emergence of a new, highly mutated COVID-19 variant that scientists have labeled BA.2.86. 

The new variant first raised concerns earlier this month after variant trackers noticed a handful of new sequences showing up in global virus databases with a large number of genetic changes different from circulating strains.

When compared to the XBB.1.5 variant, which drove a wave earlier this year and was picked out to be targeted by the upcoming fall booster shots, BA.2.86 has 36 mutations. 

Sequences of early Omicron variants in 2021 also had a similar number of mutations, when compared relative to the original strain of the virus.

BA.2.86's mutations include changes at key parts of the virus that could help the variant dodge the body's immune defenses from prior infections or vaccinations.

More could be known soon about the impacts of the strain, from experiments done by scientists testing the strain's mutations against antibodies for the virus.

Among them is Peking University Professor Yunglong Cao, whose rapid assessments of variant abilities to dodge antibodies have played a key role in helping global authorities judge the threats posed by past strains.

Cao told CBS News he expected to have some data on BA.2.86 by "early next week."

Where has the new COVID variant BA.2.86 been detected?

At least 10 infections have been reported to the global virus database GISAID or by health authorities, as of Aug. 25. Four are in Denmark, two are in South Africa, two are in the U.S., one is in Israel, and another is in the United Kingdom. 

No deaths have been reported, according to a Aug. 24 WHO report. None of the cases have a known "epidemiological link" with each other, the U.N. agency said.

The first known U.S. case was reported from a sample collected on Aug. 3, according to metadata reported to GISAID by a lab at the University of Michigan. 

A spokesperson for Michigan's health department said that sample was collected from an adult who lived in the state's Washtenaw County.

The second U.S. case of BA.2.86 was reported to GISAID from a sample collected on Aug. 10 at Dulles International Airport in Virginia.

Contractors for CDC's airport testing program had detected the case, in a woman who had traveled from Japan to the Washington, D.C. area airport.

Ohio became the third state to announce spotting the variant on Aug. 23, after the state's health department confirmed it was investigating a "preliminary detection" of BA.2.86's distinctive mutations in its wastewater. 

Marc Johnson, a professor of microbiology and immunology at the University of Missouri, said on social media the detection was based on results published this month from the CDC's sewer testing program. Those were first published on Aug. 17, from a sample collected late last month in the Ohio city of Elyria. 

A CDC official said the agency expects to be able to determine whether or not they can formally confirm the detection within the next two weeks. 

At least five other countries have also reported at least preliminary signs of BA.2.86's mutations in samples from their wastewater. 

Two countries, Switzerland and Thailand, have confirmed detections, the WHO said. Denmark announced theirs on social media. Scientists in Spain and Germany have also reported signs of mutations that could be from BA.2.86, Sorin Sion of the European Union's Sewage Sentinel System for SARS-CoV-2 told CBS News in an email. 

Do COVID tests pick up the new COVID variant BA.2.86?

Current COVID-19 tests are expected to still work for BA.2.86, based on early analyses.

"Based on BA.2.86's mutation profile, the anticipated impact on molecular and antigen-based is low," the CDC said in a risk assessment published Aug. 23.

U.S. officials have previously touted their efforts to continuously monitor the impact of variants on COVID-19 tests, in a joint effort between the Food and Drug Administration and National Institutes of Health. 

Detailed computer modeling has led to the FDA listing some tests in the past on its website that were expected to have reduced performance for previous strains.

However, manual validation efforts run by the NIH and Emory University are sometimes still needed to check whether the real-world performance of tests might slip for new variants. It is unclear whether the FDA has called for tests to be revalidated.

Doing so requires experiments using samples collected from actual humans infected by the strains, which for now remain scarce. 

Last year, the FDA said it would also urge Americans to do repeat testing with at-home COVID-19 rapid antigen tests, after NIH-backed scientists found an increase in false negative results. 

Do the symptoms of the new COVID variant BA.2.86 differ from previous strains?

There are some promising early anecdotes, but for now it is too early to know for sure whether BA.2.86 will cause new or worse symptoms.

Michigan's health department said their case was in "an older adult with mild symptoms and has not been hospitalized." The traveler in Virginia was asymptomatic, according to the metadata submitted by the CDC's contractors.

In Denmark, the country's Statens Serum Institut said their first three cases did not have symptoms "other than those normally seen in the course of COVID-19."

COVID-19 hospitalizations had already been rising around the country driven by less-mutated variants. So far, those trends do not appear to be worsening around early sightings of the strain.

"At this time, locations where this variant have been detected have not experienced increases in transmission indicators (e.g., cases, emergency department visits) or hospitalizations out of proportion to those seen in neighboring locations," the CDC said in their assessment.

Will vaccines work for the new COVID variant BA.2.86?

Upcoming vaccines are expected to help for BA.2.86, though more needs to be known. 

The variant's emergence comes as health authorities are preparing for the rollout of new COVID-19 vaccines next month, which are expected to be available soon after a meeting of the CDC's outside vaccine advisers on Sept. 12. 

Those shots were designed to target the XBB.1.5 variant, which at the time of the Food and Drug Administration's pick in June was seen as the option best suited to further broaden immunity for the virus. 

If BA.2.86 becomes dominant, Bloom thinks the strain's mutations could be enough to make those shots a poor match to fend off infections from the virus. 

However, Bloom says the body's other immune defenses could still work to blunt the strain's danger. The CDC says it currently assesses that the updated vaccine "will be effective at reducing severe disease and hospitalization." 

"I would note that while strain specific neutralizing antibodies (which can be escaped by new variants) provide the best protection against infection, there are also broader mechanisms of immunity elicited by vaccination and infection that provide some protection against severe disease," Bloom said in an Aug. 17 email to CBS News.

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• COVID-19

Alexander Tin

CBS News reporter covering public health and the pandemic.