Centers for Disease Control and Prevention Director Rochelle Walensky tested positive for COVID-19 on Friday and is experiencing mild symptoms.
Dr. Walensky is up to date with her vaccinations and is isolating at home. She will participate in planned meetings virtually, according to the agency.
All other senior CDC staff and close contacts to her have been informed and are taking steps to monitor their own health.
Last week, U.S. health regulators estimated the variants of BQ.1 and BQ.1.1 are accounting for the breakthrough of 16.6% of COVID variants in the country at this time.
The European version of the CDC said variants are likely to drive up cases in the coming weeks across the European region.
The new variants stem from the Omicron BA.5 subvariant, which has been spreading across the United States.
Recently authorized booster shots are targeted to tackle the latest variant.