MIAMI (CBSMiami) – MAST Academy, a marine magnet school in Key Biscayne, has shut down again for in-person classes after two students tested positive for COVID.

In tweet early Monday morning, that has since been removed, MAST Academy wrote, “Urgent news Makos!! We are officially back online fully. Do not show up to school. The campus is closed till further notice.”

Miami-Dade County Public Schools also sent a statement saying, “All teaching and learning at MAST Academy in Miami is taking place through My School Online (MSO) today, under a regular school schedule.”

Schools spokeswoman Daisy Gonzalez-Diego said that anyone who came into close contact with the two students was being notified using contact tracing protocols.

“The school has been thoroughly sanitized,” Gonzalez-Diego said. “The well-being of our students and employees is our top priority at Miami-Dade County Public Schools.”

At a Monday evening news conference, Superintendent Alberto Carvalho reiterated on what Gonzalez-Diego had said.

“There was subsequent sanitization, including electrostatic sanitization and an inspection,” he said.

He also encouraged individuals who may have come in contact with the infected students to stay home, adding, “If children are exhibiting symptoms do not send them to school to infect the school community. Your can contact the school directly or our emergency hotline at 305 995-1550.”

“It was almost inevitable that we could come across a number of cases in our district that would necessitate the quarantining of a classroom or children or the school itself,” he said.

Karla Hernandez-Mats, the president of the United Teachers of Dade, told CBS4’s Peter D’Oench this was a good decision.

“If there are two or more cases at a school, then it could be considered an outbreak and they should shut down and go back to virtual. That is what is done in the New York public school system. In this case, we have heard these students were at a party in Key Biscayne which is a spreading center, a spreading event for the disease.

“It’s a reminder that our kids need to wear masks and wash their hands a lot and maintain the social distancing of 6 feet. I know it is hard because these students have not seen each other in a long time,” she said.

According to the Miami-Dade County Public Schools COVID-19 dashboard, there have been nine positive cases, one employee and eight students, since schools started reopening on Oct. 5.

Two at Coral Park Elementary, and one each at Charles D. Wyche Elementary, Flagami Elementary, North Dade Center Modern Language Elementary, Poinciana Park Elementary, Royal Green Elementary, William H. Lehman Elementary and Zora N. Hurston Elementary.

At Coral Park Elementary, Sidney Sherman, whose 5-year-old son is enrolled at the school, told D’Oench, “There’s always a concern about these cases but I believe the school and the county are doing their best. It’s going to happen. It is going to happen everywhere. We must accept that these are the times that we live in.”

Hernandez-Mats also said the UTD was investigating a situation tied to Coral Reef Senior High School in which a number of parents reportedly complained that their children were not being allowed back in to the school even though they had tested negative for the coronavirus for two weeks after reportedly being exposed to a number of baseball players who had tested positive.

“Some kids at a baseball tournament did test positive for COVID,” she said. “I have been in touch with the District about protocol for allowing kids back on campus. Everything needs to be done in collaboration with the department of health and I believe there should be two negative tests before allowing kids back on campus.”

Some parents have complained to CBS4 that their children were told they could not return to school even though they had tested negative and the parents said the school said there was no established protocol for allowing students back in school.

One student was reportedly not allowed to take an English class because his teacher does not teach the course he needs to take online – she only teaches that course in person. The parents said they were getting tired of the delays in resolving this important issue.

Other reported cases not on the dashboard include the two at MAST Academy, one at Eugenia B. Thomas K-8 and one at Downtown Doral Charter School.

Broward County Schools started their staggered reopenings on Friday.

By Monday, it was confirmed that a first grader from Pembroke Pines Charter, the west campus, tested positive for the coronavirus.

A spokesperson told CBS4 News that parents have been notified and the school is following protocols.