In a series of tweets, Bill Gates says he plans to cancel most of his holiday plans and warned that that the United States “could be entering the worst part of the pandemic.”

Asserting that the Omicron variant is spreading faster than any virus in history, the billionaire and Microsoft co-founder said the big unknown remains how sick the Omicron variant can make you.

“We need to take it seriously until we know more about it. Even if it’s only half as severe as Delta, it will be the worst surge we have seen so far because it’s so infectious,” Gates said.

Gates also expects the wave to last three months in the United States.

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“Those few months could be bad, but I still believe if we take the right steps, the pandemic can be over in 2022,” Gates said.

Covid-19 cases in the United States are rising: The country averaged more than 148,000 new cases a day over the last week, 23% higher than a week ago and back to levels last seen in mid-September, according to Johns Hopkins University data.

More than 69,700 Covid-19 patients were in US hospitals on Wednesday — a number that’s been trending up since it dipped to around 45,000 on November 8, according to Health and Human Services Department data.

The US averaged 1,324 Covid-19 deaths a day over the last week, 11% higher than a week prior, according to Johns Hopkins.

Through the Bill & Melinda Gates foundation, Bill Gates has been trying to close the vaccine gap, noting that far fewer people in low-income countries have received a Covid-19 vaccines. He said in a CNN opinion story in October that the gap will get harder to close, because the world’s richer governments are buying up extra doses to serve as booster shots.

“People are right to be upset about the inequity here,” Gates wrote. “Vaccines make Covid-19 a largely preventable disease — and a survivable one in all but the rarest cases — and it is heartbreaking to know that people are dying of a disease not because it can’t be stopped but because they live in a low-income country.”

— CNN’s Aya Elamroussi contributed to this report

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