Scientists around the world are working to learn more about the omicron variant of COVID-19. The variant, found in nearly 40 countries, was first confirmed in the U.S. on Dec. 1. Since then, health officials in 40 states, and the District of Columbia, have confirmed their own cases of the variant.
What do we know so far?
Omicron, designated by the World Health Organization as a "variant of concern" in late November, was first reported in South Africa. Its country of origin is unclear. WHO said it is currently unknown whether the omicron variant has different symptoms or is more transmissible than other variants.
The variant appears to have been behind a recent spike in COVID-19 infections in South Africa.
In the U.S., Pres. Joe Biden said shortly after the discover that the variant is a cause for concern, not panic. He renewed his call for Americans to get COVID-19 booster shots. Health officials urged Americans to keep following standard COVID-19 precautions like social distancing and wearing masks indoors.
The World Health Organization said on Dec. 9 that early evidence suggests the omicron variant may be spreading faster than the highly transmissible delta variant but brings with it less severe coronavirus disease -- but cautioned that it was only “anecdotal information."
Where has the omicron variant been found in the U.S.?
Here is a look at which states have reported their first cases and when those cases were announced. Beyond these confirmed cases, its actual spread in the U.S. is unclear.
Alabama
The Alabama Dept. of Public Health confirmed Dec. 16 that an Alabama resident has been confirmed as the state's first case of the COVID-19 omicron variant.
Alaska
The Anchorage Health Department announced the state's first case of the COVID-19 omicron variant was confirmed on Dec. 13. Health officials said in a press release that the person who tested positive was an Anchorage resident who had returned home following international travel in November.
Arizona
The state's first case of the COVID-19 omicron variant was confirmed Dec. 8. in Yavapai County. No information was given about the patient or where the may have contracted the virus.
Arkansas
Gov. Asa Hutchinson announced Dec. 17 that Arkansas has confirmed its first case of the omicron variant.
"This was expected, and we expect more cases of the variant to be confirmed in the near future. This is not a surprise, but it is a compelling reason to get a booster shot now," Hutchinson tweeted.
California
The first confirmed case in the U.S., announced Dec. 1, was a person who had returned from South Africa, developed mild symptoms and tested positive for COVID-19. The patient was fully vaccinated but was not yet due for a booster dose. A second case was confirmed the next day in California.
Colorado
Colorado health officials announced on Dec. 2 that a woman was confirmed to have the omicron variant after a trip to several countries in southern Africa. She had traveled through the Denver International Airport. The woman was fully vaccinated against the virus but had not received a booster shot.
RELATED: Polis urges vaccinations, booster shots after first omicron variant case reported in Colorado
Connecticut
On Dec. 4, Gov. Ned Lamont said Connecticut had confirmed its first case of the omicron variant. A man in his 60s tested positive after one of his family members attended the Anime NYC 2021 convention in New York City. Both he and the family member had mild symptoms and are fully vaccinated.
Minnesota's first omicron case was in a man who had also traveled to the Anime NYC 2021 convention.
District of Columbia
DC Health said Dec. 12 that it confirmed the District's first four cases of the omicron variant of COVID-19.
The four cases are unrelated. DC Health released the following information about the cases. The first case is a woman who traveled domestically to Florida and New York. She had been fully vaccinated and was eligible for the booster vaccine but had not received it yet. DC Health Contact Trace Force has already reached out to all close contacts and has already provided them with guidance.
Florida
Florida health officials have confirmed a case of the omicron variant found in Tampa.
A hospital patient was diagnosed with the variant Dec. 7, and is presenting with mild symptoms. The person recently returned from international travel.
Georgia
Georgia health officials reported the state's first in-state omicron case Dec. 4. The infected person, who had recently traveled to South Africa, was fully vaccinated and had gotten a booster dose.
Hawaii
State health officials confirmed the variant Dec. 2 in an unvaccinated Hawaii resident with no recent travel history. The person, who lives on the island of Oahu, had had “mild-to-moderate” symptoms. They had previously been infected with COVID-19 a year ago.
Idaho
Central District Health announced Dec. 10 that it has confirmed Idaho's first COVID-19 case with the omicron variant.
The variant was found in a clinical lab sample from an Ada County resident who recently reported out-of-state travel.
Illinois
The Illinois Department of Public Health reported that state's first omicron case on Dec. 7 in a Chicago resident who had been in contact with someone from another state who had also tested positive for the variant.
Indiana
The Indiana State Department of Health announced Sunday, Dec. 19 that it had detected the omicron variant of the COVID-19 virus in a specimen collected from an unvaccinated Indiana resident, as WTHR reported.
The sample was collected Dec. 9, and omicron was later detected in the sample after sequencing was conducted.
Iowa
Iowa health officials announced the state's first confirmed omicron case on Dec. 9. They said an unvaccinated minor who had been traveling was infected with the variant. The minor was asymptomatic at the time of the announcement.
Kansas
Kansas confirmed its first case of the omicron variant on Dec. 16.
The Kansas Department of Health and Environment said in a news release that the infected person is a vaccinated adult in Franklin County in the northeast part of the state. The person had not received a booster. The health department said no additional details would be released to protect the patient's privacy.
Kentucky
Kentucky had its first case of the omicron variant of COVID-19, Gov. Andy Beshear said in a tweet on Dec. 17. No details about the case were immediately released.
Louisiana
Louisiana's health department announced Dec. 5 that it had confirmed the state's first case of COVID-19 caused by the omicron variant of the coronavirus.
Testing of a probable case of the new variant determined omicron caused the COVID-19 infection in a person who lives in the New Orleans area and recently traveled within the United States, according to the agency.
Maine
Public health officials in Maine said on Dec. 17 the state detected the omicron variant of COVID-19 within its borders. The Jackson Laboratory in Bar Harbor conducted genomic sequencing to confirm the variant in five samples from Penobscot County, the Maine Center for Disease Control and Prevention said.
Maryland
Maryland health officials confirmed the omicron variant in three state residents, Gov. Larry Hogan announced on Dec. 3. Two are from the same household, including a vaccinated person who recently traveled to South Africa and an unvaccinated close contact. The third case, a vaccinated person with no known recent travel history, is unrelated to the other two. None of them are hospitalized.
Massachusetts
Massachusetts health officials said on Dec. 4 that a fully vaccinated woman in her 20s tested positive for COVID-19 after traveling out of state. Genetic sequencing confirmed that it was the state's first case of the omicron variant. The woman had mild symptoms and was never hospitalized.
Michigan
Michigan's first case of the omicron variant of COVID-19 was identified on Dec. 9 in a Kent County resident, the state Department of Health and Human Services and Kent County Health Department said.
Minnesota
Minnesota health officials announced on Dec. 2 that a man who had attended a New York City anime convention tested positive for COVID-19 in late November. He was later found to have the variant. The man was fully vaccinated and had gotten a booster dose earlier last month.
Mississippi
Mississippi health officials announced on Dec. 6 that a person who recently had been in New York has tested positive for the omicron variant. According to the Mississippi State Department of Health, the individual is fully vaccinated and did not have to be hospitalized.
Missouri
Missouri health officials announced the state's first case of the omicron variant on Dec. 3. They said the infected person is a St. Louis County resident who had recently traveled domestically.
"The sample was originally sequenced as part of commercial laboratory surveillance and results are currently awaiting confirmation by the CDC," state health officials wrote.
Nebraska
Nebraska health officials announced six confirmed cases of the omicron variant on Dec. 3 -- one person who had likely been exposed while traveling to Nigeria late last month, and five others who were probably exposed through household contact with that person.
Health officials said only one of the six people were vaccinated, and none have required hospitalization.
Nevada
The Southern Nevada Health District confirmed on Dec. 14 the state’s first case of COVID-19 caused by the Omicron variant. The individual was a fully-vaccinated woman in her mid-20s, who had not yet received a booster shot.
New Hampshire
The New Hampshire Department of Health and Human Services announced on Dec. 13 that it has identified the first case of the omicron variant in a New Hampshire resident. Officials said in a press release the individual had traveled out-of-state and was exposed to another person who later was identified with the Omicron variant infection. The New Hampshire resident, who was considered fully vaccinated but was not yet boosted, had a mild illness and has since recovered during home isolation.
New Jersey
Health officials said on Dec. 3 that a Georgia resident is self-isolating in New Jersey after being confirmed to have the omicron variant. The person traveled from South Africa and was in Georgia for two days before traveling to New Jersey, where testing and sequencing confirmed the variant's presence. So far, no additional Omicron cases in Georgia have been identified.
New Mexico
The Department of Health in the state of New Mexico confirmed that state health officials there have detected the first case of the COVID-19 variant omicron.
In a statement, health officials said "The case was identified Sunday, December 12 and is a female adult...The individual reported recent domestic travel to a state with reported cases of Omicron. The individual was seen in a local emergency room and discharged stable to home."
New York
New York Gov. Kathy Hochul said as of Dec. 2, her state has confirmed five cases of the omicron variant.
North Carolina
A student at UNC Charlotte tested positive for the omicron variant of COVID-19, marking the first confirmed case of the variant in Mecklenburg County, health officials announced Dec 10.
Ohio
Health officials have reported Ohio's first known cases of the omicron variant on Dec. 11. The two cases were detected in two adult men who had received an initial vaccine dose but not a booster dose. Their symptoms were mild and they weren't hospitalized.
Oregon
The Oregon Health Authority said on Dec. 13 that three cases of the omicron variant were detected in the state — in Multnomah and Washington counties.
Pennsylvania
Health officials reported the first confirmed case of the omicron variant in Pennsylvania on Dec. 3, a man in his 30s from Philadelphia. No other details were immediately available, including whether the man was vaccinated against COVID-19 or if he had been traveling.
Rhode Island
Rhode Island Governor Dan McKee and the Rhode Island Department of Health announced Dec. 11 the state's first case of the omicron variant.
South Carolina
Scientists at the Medical University of South Carolina announced on Dec. 15 that they had identified three positive cases of the omicron variant in patients in the state.
It is unclear if the three patients had recently traveled anywhere.
Tennessee
On Dec. 11, the Shelby County Health Department said two omicron cases had been identified in Tennessee. Health officials did not say whether the people who tested positive had been traveling or were vaccinated.
Texas
Texas reported its first omicron case on Dec. 6 as a woman living in Harris County who had not traveled anywhere recently.
Utah
Utah health officials said on Dec. 3 that an older adult who had recently traveled to South Africa was confirmed to have the omicron variant. The person, who is fully vaccinated, had mild symptoms and received monoclonal antibody treatment.
Virginia
Virginia health officials said on Dec. 9 that the state had its first case of the COVID-19 omicron variant. The Virginia Department of Health shared said the person infected had not traveled internationally recently but had traveled within the United States.
Washington
On Dec. 4, health officials confirmed three cases of the omicron variant in the state of Washington. The three cases were detected in different counties and aren't thought to be related.
West Virginia
Gov. Jim Justice and state health officials announced on Dec. 16 that a case of the omicron variant has been confirmed in the state for the first time.
“It’s not good news, but we knew it was coming. It’s running across the entire country and the entire globe.” Gov. Justice said.
Wisconsin
Wisconsin health officials announced the state's first omicron case on Dec. 4. The infected person, a fully vaccinated man who had gotten a booster shot, had mild COVID-19 symptoms after a recent trip to South Africa.
RELATED: Wisconsin reports first omicron case
Wyoming
The Wyoming Department of Health on Dec. 17 confirmed the state's first case involving the omicron variant. Officials said in a press release that the first case involved an Albany County adult who had recently traveled within the country.
The Associated Press contributed to this report.