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The head of the US Centers for Disease Control and Prevention urges counties with high Covid-19 community levels to encourage people to mask up in public indoor settings.

US counties with high Covid-19 community levels should encourage people to put their masks back on while indoors and people in areas with medium levels should consider masking based on their own Covid-19 risk, CDC Director Dr. Rochelle Walensky said in a White House briefing Wednesday.

That impacts about a third of people in the United States.

More than 32% of people nationwide live in areas with medium or high Covid-19 community levels, Walensky said. That breaks down to 9% living in areas with high Covid-19 community levels and 23% living in medium areas.

For areas currently with high Covid-19 community levels, “we urge local leaders to encourage the use of prevention strategies like masking in public indoor settings and increasing access to testing and to treatment,” Walensky said.

“In areas where community levels are high, everyone should be using prevention measures and wearing a mask in public indoor settings,” she said.

In areas with medium levels, Walensky said “individuals should consider taking prevention measures based on their own risk, like avoiding crowds, wearing a mask, increasing their testing, especially before gathering with others indoors.”

In any Covid-19 community level, Walensky said that people “may always choose to wear a mask to protect themselves from infection.”

As of Wednesday, about 4.25% of US counties have high Covid-19 community levels, according to CDC data.

“As we’re currently seeing a steady rise of cases in parts of the country, we encourage everyone to use the menu of tools we have today to prevent further infection and severe disease, including wearing a mask, getting tested, accessing treatments early if infected and getting vaccinated or boosted, especially if you’re over 50 and if your last dose was more than five months ago,” Walensky said.

While cases are not peaking, Walensky warned of an upward trend in cases and hospitalizations.

“While cases remain much lower than during the Omicron surge this past winter, the current seven-day daily average of cases is now at about 94,000 cases per day, which is an increase nationally about 26% over the previous week, and a three-fold increase over the last month,” Walensky said.

“Similarly, hospital admissions are also increasing but remain much lower than they were during the Omicron surge. The seven-day average of hospital admissions now is about 3,000 per day and that’s an increase of about 19% over the previous week,” she added. “While deaths do remain low, we are still seeing a tragic seven-day average of daily deaths at about 275 per day.”

Northeast sees high Covid-19 community levels

Many counties in the northeast region of the country currently have high Covid-19 community levels, and about 40% of people in the northeast are in counties considered to have high community levels.

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“The highest levels are currently throughout the state of New York and Connecticut, Massachusetts, Maine, New Jersey,” Lori Tremmel Freeman, chief executive officer of the National Association of County and City Health Officials, told CNN on Wednesday.

Freeman pointed to the fast-spreading Omicron subvariants, BA.2 and BA.2.12.1, as possible drivers of Covid-19 transmission in those regions and the nation as a whole.

About half – 50.9% – of Covid-19 cases in the US are caused by BA.2 and about the other half – 47.5% – are caused by BA.2.12.1, according to CDC data.

“BA.2.12.1 is 25% more contagious than BA.2, which we know is very contagious,” Freeman said. “So, they expect that that variant will be dominant shortly.”

Deidre McPhillips contributed to this report.