We could see lockdowns return in areas with low COVID-19 vaccination rates, Treasury Secretary says

Federal Reserve Chair Janet Yellen speaks during a news conference December 13, 2017 in Washington, DC.

Treasury Secretary Janet Yellen on Friday said the U.S. could see lockdowns return in parts of the country with low COVID-19 vaccination rates. 

According to Wisconsin state health officials, 51% have received at least one dose.

Yellen's remarks were in response to a question from CNBC’s Sara Eisen, who asked about the possibility of lockdowns returning and whether the U.S. economy could handle them.

"So, I mean, we have solid rates of vaccination in many parts of the country," Yellen said. "But certainly it, it’s something that could, could happen in areas where vaccination rates are low so it really is critically important that we maintain progress on vaccinating more Americans."

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The COVID-19 curve in the U.S. has begun rising again after months of decline, with the number of new cases per day doubling over the past three weeks, driven by the fast-spreading delta variant and lagging vaccination rates.

Confirmed infections climbed to an average of about 23,600 a day on Monday, up from 11,300 on June 23, according to Johns Hopkins University data. 

Nationally, 55.6% of all Americans have received at least one COVID-19 shot, according to the Centers for Disease Control and Prevention.

The five states with the biggest two-week jump in cases per capita all had lower vaccination rates: Missouri, 45.9%; Arkansas, 43%; Nevada, 50.9%; Louisiana, 39.2%; and Utah, 49.5%.

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