Most high school seniors nationwide who are back in their classrooms took a mock test for this year’s college entrance exam Thursday, a day after schools physically reopened.

The mock exam comes as plans to resume in-person classes continue to be disrupted by new COVID-19 infections involving high school seniors who are in a race against time until the national test in December. 

A high school in Daegu was closed down Thursday after its student tested positive for the coronavirus. The student was among the 17 students who got tested before moving into a school dormitory Wednesday. The patient was asymptomatic, according to the Daegu’s education office.

The dorm inhabitants were put in isolation and other third graders were ordered to return home. The third graders and all teachers and employees will be tested for the virus, according to health authorities. 

Under the guidelines on response to COVID-19 infection at schools, schools that see a confirmed patient will be shut down for two days and turn to remote learning.

Hosted by the Gyeonggi Provincial Office of Education, the mock exam is virtually the first opportunity for third-year high school students to see where they stand on a national scale and explore possible options for college applications.

The previous mock test, organized last month by the Seoul Metropolitan Office of Education, was held online as schools were physically shut amid spread of the coronavirus. The test results were not provided.

Attended by some 77.6 percent of the country’s high schools, or 1,835 schools, the mock test covers five subjects from Korean language to mathematics, with the test results to be released starting June. 5.

Students attending 66 schools in five districts in Incheon, where two high school third graders tested positive for the virus on the first day of school reopening Wednesday, sat the exam online, as schools were closed again. Incheon’s education office is to decide on whether to resume in-person classes Friday.

Students at nine schools in Anseong, Gyeonggi Province, which reopened Thursday, took the exam as scheduled. The school postponed its reopening amid incomplete contact tracing for a patient confirmed to be infected Wednesday.

About 450,000 high school seniors on Wednesday returned to classrooms nearly three months later than usual. The students, who had attended classes online, were the first group to go back to school, given a hectic academic calendar until they sit the college entrance exam scheduled for Dec. 3.

Despite lingering safety concerns, health and education authorities are adamant that reopening of schools should continue, with daily quarantine practices in place.

“About the reopening of schools for high school seniors, we cannot help but continue to see confirmed patients because the virus might be spreading quietly in communities. The thing is how fast we discover the patients, respond and calmly take action,” Kwon Jun-wook, deputy director of the Korea Centers for Disease Control and Prevention, said at a briefing Thursday.

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)