At least a dozen public high schools across New Jersey have switched back to all-remote instruction this fall due to cases of novel coronavirus within the school population.

The suspension of in-person instruction lasted only a few days for some, while others have shut their buildings for 14 days or more, depending on whether the cases can be considered an outbreak under state Department of Health guidelines.

State health officials issued a COVID-19 Regional Risk Matrix, last updated Sept. 8, which provides public health recommendations among positive cases and possible exposure of students and staff, as well as the type of instruction (in-person, hybrid or all-remote).

As of the week ending Sept. 19, the majority of the state was assessed as having a "low" COVID-19 activity level, except for the Central East region at "moderate." That region encompasses Middlesex, Monmouth, Ocean and Union counties.

Under the state guidance, any region considered at moderate activity should "consider a mixture of remote and/or hybrid learning approaches, and/or fully remote learning."

An outbreak in school settings is defined as two or more laboratory-confirmed COVID-19 cases among students or staff with onsets within a 14-day period, who are epidemiologically linked, do not share a household and were not identified as close contacts of each other in another setting during standard case investigation or contact tracing, according to state guidance.

When asked Tuesday about any known cases of in-school transmission, the state Health Department repeated a statement Health Commissioner Judith Persichilli said at the Sept. 23 state briefing, that New Jersey was “beginning to receive reports of positive cases in our schools. Each case is being investigated and contact-traced to determine if there is in-school transmission. Our goal is to identify, isolate and mitigate as quickly as possible and share that information when it is complete.”

On Tuesday, Morristown High School went to three days of all-remote, pending further test results after one positive case among the school community as of Friday and another member showing symptoms. The same update posted online said a total of 37 people were being quarantined for at least 14 days amid contact tracing for those individuals.

Ramsey High School also moved to all-remote instruction Tuesday, as reported by NorthJersey.com, but some students already had showed up for previously planned in-person instruction. The same report said it was prompted by a staff member's coronavirus test result.

In Union County, Westfield High School went to all-remote learning for two weeks as of Sept. 18 after seven high school students tested positive. More than 30 other Westfield High School students were quarantining at home, after saying that they had direct exposure with someone who was positive, according to the district schools superintendent, who also said in the same update that "exposure in all those cases occurred outside of Westfield High School."

In Gloucester County, Washington Township High School had one staff member and several students test positive, prompting all-remote learning for several days, until this week.

In Mercer County, Hopewell Valley Regional School District transitioned to all-remote learning from Sept. 16 until Monday, Sept. 21, after one case of COVID-19 was confirmed among the school.

In Burlington County, Lenape Regional High School went to all-remote classes on Sept. 18 after two COVID-19 cases were confirmed. The school reopened for hybrid learning on Sept. 21.

Mahwah High School switched to all-remote learning for at least a week as of Sept. 21, amid a positive case of COVID-19 within the district.

Passaic Valley Regional High School began the school year in a hybrid learning model and then switched to all-virtual learning from Sept. 21 through Oct. 5. There was no specific mention of any positive cases confirmed, in the announcement on the school's Facebook page.

Pompton Lakes High School switched from a hybrid learning model to all-remote learning from Sept. 15 through Sept. 25 after three students and a staffer tested positive for COVID-19, as reported by NJ.com.

In East Brunswick, the Middlesex County Vocational and Technical Schools campus went to all-remote between Sept. 10 and Sept. 21 after a student tested positive, as reported by CentralJersey.com.

Chatham High School switched to remote learning Sept. 9, just two days into its planned hybrid instruction, after a student tested positive. The school reopened Tuesday.

In Passaic County, Pompton Lakes High School moved to all-remote learning Sept. 15 through Sept. 29 after three high schoolers and then a staff member tested positive within a week of each other.

Morris Hills High School in Rockaway and Morris Knolls High School in Denville in the Morris Hills Regional District went all-remote for two weeks as of Sept. 14, not due to positive cases but instead because the wrong air filters were installed in some classrooms in the schools' HVAC systems.

With previous reporting by Dan Alexander

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