WASHINGTON – US Senator Elizabeth Warren has tested positive for Covid-19 despite receiving a booster shot against the virus.

The Democratic Senator from Massachusetts tweeted that her regular test resulted in a negative result last week, but that she "tested positive with a breakthrough case" on Sunday. Warren stated that her symptoms were minor and that she was "grateful for the protection provided against serious illness that comes from being vaccinated and boosted."

It's unclear whether Warren has contracted the highly transmissible Omicron variant that's causing Covid-19 outbreaks in the United States. Anthony Fauci, the country's top infectious disease expert, warned that Omicron is "going to take over" the United States this winter, urging Americans to get fully vaccinated and boosted.

On Tuesday, UN President Joe Biden is expected to deliver an Omicron-focused speech. The administration is "prepared for the rising case levels," according to White House Press Secretary Jen Psaki, and the President will detail how they will respond to the challenge.

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