Residents in nearly two dozen counties in upstate New York are now being recommended to wear masks due to high case-counts of COVID-19, according to new data from the Centers for Disease Control and Prevention.

Twenty-three counties across the region, up from 10 a week ago, are now classified by the CDC as having "high" community levels of the coronavirus, ranging from Western New York to the Capital Region.

In addition, three counties just over the New York border in northern Pennsylvania — Susquehanna, Bradford and Sullivan — also have a “high” rating.

As of Friday, the 23 upstate counties are among just 40 counties in total across the U.S. that are currently under the "high" category.

The CDC uses a "high," "medium" and "low" classification, which is determined by the number of new cases in the county per 100,000 people in the past seven days; the number of new hospital admissions with COVID-19 in the past seven days per 100,000 people; and the percentage of staffed inpatient beds in use by patients with COVID-19 within a seven-day average.

With a "high" level, the CDC recommends wearing masks in indoor public areas and on public transportation. 

The New York state Department of Health recommended mask-wearing in three Central New York counties on April 1. There are currently no local mask requirements in these areas, outside of the statewide requirement for them in bus and train stations, prisons, state-regulated care settings and homeless shelters.

Earlier this month, the Central New Yok region was the first in New York to have confirmed cases caused a new BA.2 omicron subvariant known as BA.2.12, state officials said at the time. 

According to state data released Thursday by Gov. Kathy Hochul’s office, the state’s seven-day average of COVID-19 cases per 100,000 people stood at 31.36. In recent weeks, New York health officials and those in other states have started using cases per 100,000 residents, and not the more traditional percentage of positive results of those who have been tested, as a more accurate way of measuring infection rates.