The Centers for Disease Control and Prevention’s updated mask guidance now applies to nine Massachusetts counties, according to data released Monday.

That is up from five counties last week.

The guidance issued last week recommends that everyone in a place with a “substantial” or “high” coronavirus transmission rate wear a face covering in indoor, public places regardless of vaccination status.

According to CDC data collected during the week that ended Saturday, Barnstable and Nantucket counties are in the “high” transmission rate category.

Bristol, Essex, Hampden, Middlesex, Plymouth, Suffolk and Worcester counties are in the “substantial” zone.

Provincetown, which had a cluster of about 900 confirmed cases stemming from July Fourth celebrations, is in Barnstable County. Town Manager Alex Morse posted on social media Monday that the number of active cases and daily percent positive rates continue to decline and “we are well on our way to containment.”

Of those cases, only seven hospitalizations and no deaths have been reported.

The percent positive rate peaked at 15 percent on July 15 and was down to 3.3 percent Saturday and 4 percent Sunday, he said. The cluster was blamed on the highly-contagious delta variant.