How serious is omicron? It will take weeks to understand new coronavirus variant, experts say.

Three questions loom about the newly detected omicron variant of the coronavirus: Is it more transmissible than delta? Does it make people sicker? How much protection does vaccination or a prior infection provide against it?

The answer to all three is an unsatisfying “We don’t know yet.”

People are in for an anxious couple of weeks as data is collected, patient records are scoured, hospitalizations are tracked and blood samples are tested.

Only then will we know whether this is another delta variant, fast-moving and highly contagious, or something like a gamma, which appeared, sputtered out and quickly disappeared.

“This is the way science works,” said Dr. Alex Greninger, an assistant director of the clinical virology laboratories at the University of Washington Medical Center in Seattle. “It’s just that the stakes of the science have never been higher.”

Read more: Everything to know about the latest COVID-19 strain

Sunday, national health adviser Anthony Fauci told President Joe Biden it will take approximately two weeks to have more definitive information on the transmissibility, severity of infection and other characteristics of the omicron variant.

In a news conference Monday, Biden assured Americans, "We're learning more about this new variant every single day, and as we learn more, we're going to share that information with the American people candidly and promptly."

The World Health Organization has begun coordinating with researchers around the world to better understand the variant.

Wednesday, South Africa reported the newly discovered variant of the SARS-CoV-2 virus, which causes COVID-19. It had a large number of mutations, several of which are associated with being more contagious or better able to evade immune system protections.

Two days later, WHO designated omicron a “variant of concern,” and the hunt for answers was on.

There are some indications omicron may be more transmissible than delta, based on the rate at which case numbers are rising in countries reporting the variant and anecdotal reports of outbreaks on international flights, said Dr. Charles Chiu, a professor of medicine and infectious disease at the University of California, San Francisco School of Medicine.

"There is early evidence of this, including a tripling of hospitalizations in South Africa, Gauteng province, over the past three weeks thought to be from omicron," he said. 

Over the weekend, Greninger checked on cases rates in South Africa.

“Less than a week ago, they were at 500 cases a day, and now they’re at 3,000 cases. That’s a pretty big jump,” he said.

It will take several weeks of data collection and testing to see whether the surge is  driven by omicron or the prevalent delta variant.

The omicron variant has been detected in Botswana, South Africa, Canada, the United Kingdom, Germany, Italy, Denmark, the Netherlands, Australia and other countries.

To give a sense of how fast a variant can supplant an existing version of a virus, the delta variant was more than twice as contagious as the alpha mutation, which in turn was 50% more contagious than the original virus identified in Wuhan, China.

Delta was first detected in the U.S. in March and by August was responsible for 98% of cases in the country.

Sign up for USA TODAY's Coronavirus Watch newsletter to receive updates directly to your inbox. You can also join our Facebook group.

Omicron, the newest coronavirus variant: How to pronounce it, how it got its Greek name, and what it means

More disease or more severe disease?

Another pressing concern is whether omicron causes more severe disease than delta.

The World Health Organization said Sunday that reported infections were mostly among university students, younger people who tend to have more mild disease. Understanding the level of severity caused by the omicron variant “will take days to several weeks,” WHO said. 

That leaves open the question of whether it’s more dangerous in the elderly, as delta is.

“We don’t know if it’s going to be more virulent in older people," said Dr. Susan Kline, a professor of infectious diseases at the University of Minnesota Medical School. "That’s just going to take a few weeks. We’ll just have to learn through experience, through the types of patients who get admitted to hospitals."

Careful testing and tracking will be necessary to see whether omicron is more dangerous than delta. Doctors will track whether a higher percentage of omicron patients develop severe disease or die, compared with rates among delta patients.

It could be the new variant is not inherently more pathogenic or dangerous but simply spreads and causes infection more easily, resulting in many more infected people.

How evasive is omicron?

Early evidence suggests people who have recovered from COVID-19 could become reinfected more easily by omicron, but data is limited.

“More information on this will become available in the coming days and weeks,” WHO said in a news release Sunday.

There’s no evidence omicron can overcome the protection of vaccination.

“We can be somewhat reassured no variant to date, and no combination of spike mutations in any variant, has been shown to greatly impact the effectiveness of the vaccine in preventing hospitalizations and deaths,” Chiu said.

In South Africa, the majority of hospital admissions for omicron have been among the unvaccinated. Scientists are testing the variant to see if antibodies from vaccination or natural infection can protect against it, but the results won’t be known for several weeks.

U.S. scientists wait for access to omicron virus cultures.

There aren’t any documented omicron cases in the USA, so researchers don’t have the necessary virus cultures to do the tests.

It’s possible to ship virus samples within the United States, though they must be specially packaged and shipped as well as having proper documentation and labels which disclose that the package contains an infectious agent.

Getting virus samples from overseas is a challenge and often delayed due to export restrictions and other regulations on their transportation and use, said Chiu.

Given the number of omicron cases discovered around the world in the past few days, it’s likely it will be found here. Dozens of labs and hospitals are ready to begin testing.

“You have to have the omicron strain, and then you have to have patient blood and then test their neutralizing antibodies against the new strain," Kline explained. "Those sorts of experiments would take a few weeks."

Contact Elizabeth Weise at