Florida and Illinois are the latest states to announce cases of the omicron COVID-19 variant in the country.
The new cases were reported a day after Centers for Disease Control and Prevention director Rochelle Walensky said Tuesday during a White House briefing that 19 states had confirmed cases of the "variant of concern."
In Florida, a case was detected at a Tampa hospital and officials are working to confirm another in St. Lucie County, Fox 35 reported.
"Florida stands ready to respond through our system of prevention and treatment," the state's department of health said in a statement. "Rather than focusing on one solution, the state of Florida will continue to adapt as necessary to protect public health as we have done with previous variants of concern and throughout the COVID-19 response."
Illinois also announced its first known omicron case.
In a joint statement, the Illinois and Chicago departments of public health said the case was identified in a Chicago resident who had been a contact of another confirmed omicron case from a different state who had visited the area.
"The Chicago resident – fully vaccinated with a booster dose – did not require hospitalization, is improving and has been self-isolating since their symptoms began. Public health officials continue to perform contact tracing," the departments wrote.
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Gov. J.B. Pritzker called on residents of the states to follow COVID-19 protocols including getting booster shots, masking up indoors, getting tested and keeping hands clean.
Chicago Mayor Lori Lightfoot echoed that message, saying it is "crucial" residents continue to get vaccinated and receive boosters.
Cases have also been reported across the nation, from New York to Hawaii, with the first known case of omicron detected in a San Francisco resident last week.
And yet, while CDC and state and local officials have assured that contact tracing to track omicron's spread is ongoing and Walensky said she expects the number of states with cases linked to the variant to increase, more than 99% of COVID-19 cases in the country are tied to the delta variant.
As the weather has turned colder, daily cases in the U.S. have risen to nearly 119,000.
Still, it will take more weeks before scientists can truly begin to understand omicron's abilities, including its severity.
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The CDC and experts say current vaccines will provide some protection against omicron and Pfizer CEO Albert Bourla told NBC's "Today" show on Wednesday that a booster shot would be enough to "maintain protection" against omicron.
In a Tuesday interview with Agence France-Presse (AFP), America's top infectious disease expert Dr. Anthony Fauci said omicron is "clearly highly transmissible" and that more laboratory experiments testing the potency of antibodies from current vaccines against omicron are expected in coming days.
The Associated Press contributed to this report.