SAN RAFAEL, Calif. (KRON) – A spike in COVID-19 infections brings back mask requirements to a North Bay school.

School leaders at Coleman Elementary in San Rafael have confirmed more than 20 cases since last week.

The return of the indoor mask mandate at Coleman Elementary comes just weeks after the mandate was lifted.

A spokesperson for San Rafael city schools says that since March 22nd six employees and 17 students have tested positive for COVID-19.

Families have been told the masks will stay on until at least April 15th.

Dr. John Swartzberg with UC Berkeley’s school of public health says COVID-19 variants including the highly transmissible BA.2 subvariant of omicron are still circulating.

“It’s not surprising to see groups of kids getting infected. We know that if children wear masks indoors in schools it’s going to reduce the transmission of the virus,” Dr. Swartzberg told KRON4.

The Centers for Disease Control and Prevention reports that more than half of the cases in the western U.S. are BA.2.

But Dr. Swartzberg says the spike in infections at Coleman is nothing to be too concerned about just yet.

“It’s going to happen but as long as it’s sporadic like this I’m not really concerned. We’re in a very very good period right now”, he said.

In a letter to Coleman Elementary families about reinstating the mask mandate, Principal Mike Taylor said “I want to emphasize that this is not a time for alarm, but for us to implement the recommended public health strategies to respond to an uptick in cases and decrease risk of transmission.”

Students and staff were also given COVID-19 rapid tests before leaving for spring break Friday.

The district reports there have been very few COVID-19 cases since the mask mandate was lifted on March 12th.

However, a large number of students and staff are still wearing masks at schools.