Outbreaks of COVID-19 infections in some schools in Sequim, Port Angeles and Port Townsend have prompted masking recommendations for students and staff.

Dr. Allison Berry, health officer for Clallam and Jefferson counties, said Thursday that in-school transmission is being seen on the North Olympic Peninsula.

A masking recommendation also has been issued for a third-grade class at Greywolf Elementary School in Sequim. The number of students who had tested positive was not provided. Students and staff are asked to wear masks through Sept. 30.

As of Wednesday, 22 students and staff members at Stevens Middle School in Port Angeles had tested positive for the virus within the past week, according to a letter Principal Kristen Lunt sent to parents on Wednesday.

“Many were on campus during their contagious periods,” the letter said.

Officials recommend that students and staff wear masks while indoors at the school through next Wednesday.

The Port Angeles School District submits its COVID-19 reports every Friday, according to Carmen Geyer, district spokesperson, so if there are more cases, they will be reported today.

Blue Heron Middle School in Port Townsend reported at least 10 cases in its seventh-grade class earlier this week and has urged its students and staff to wear masks until the end of the day today.

School officials took additional measures throughout the week to separate its seventh- and eighth-grade classes during lunch periods. The district also gave all students masks and tests to take home, as well as more tests and masks at the student service window.

“The Jefferson County Health Department asks that all students who are ill, regardless of testing positive or negative for COVID, stay home,” said Port Townsend School Superintendent Linda Rosenbury in an email.

“Additionally, they ask you to test your child before they return to school on Monday.”

Berry said having three or more related cases in a school system qualifies as an outbreak.

“It doesn’t have to be large to meet the outbreak requirement, but we are certainly seeing transmission in schools,” Berry said.

“It is not entirely surprising given that so many kids do not mask and we are still seeing a lot of transmission in the community,” she added.

“What happens when we have an outbreak is we identify the location. It’s usually in a single grade at this point, and what we do in those cases is recommend masking for a period of a week in that grade.”

Berry said that is easier to do in an elementary school “where they don’t move around as much. It gets harder at the middle and high school level.”

As of Thursday, the case rate in Clallam County was 186 cases per 100,000 population, and the case rate in Jefferson County was 364 cases per 100,000. Case rates are computed using a formula based on 100,000 population even for counties that do not have 100,000 people living in them.

Other districts across the Peninsula have reported single cases in their schools, not enough to trigger masking recommendations.

Chimacum School district reported Thursday that one staff member was out with COVID-19, but that person is expected to be cleared to return to work next week.

Quilcene School District reported one student and one staff member out with COVID-19, with both parties staying home.

Quillayute Valley School District reported that some students have tested positive but that there has been no in-school transmission and that those students have stayed out of school until no longer contagious.