Most high school seniors here returned to school on Wednesday, but some schools were forced to postpone physical reopening due to virus-related risk factors, related officials said.

Two high school seniors in Incheon tested positive for COVID-19, leading the school they attended as well as two nearby high schools to delay resumption of in-person classes by a day, according to the city’s education office.

Students at 66 high schools across five districts in Incheon were directed to go back home on Wednesday morning over concerns they could have crossed paths with the diagnosed students, both of whom frequently used crowded facilities.

“It is difficult to speak in terms of numbers (about when schools would be directed to close). Decisions will be made based on the situation in each region. A differentiated approach should be taken (on reclosure) after drawing clear boundaries of areas and schools exposed to danger (if students test positive),” Director General of Korea Centers for Disease Control and Prevention Jung Eun-kyeong said at a press briefing.

“Our concern is, if we believe COVID-19 will somewhat die down, it would be preferred to reopen schools then. But given that the situation will not change in the second half of this year, we believe that we should look for ways to carry out both our daily activities in a safe manner and take measures to prevent the virus.”

Officials with the city’s education office were in talks with health authorities to decide when to reopen concerned schools.

The 18-year-old students were confirmed positive for the virus after visiting a karaoke establishment that had been visited earlier this month by another student connected with an educator in Incheon, who is believed to be the initial source of infection.

The number of patients linked to the karaoke establishment totaled 27, as of Wednesday, health authorities said.

“We can proceed with in-person classes when students and staff are safe from COVID-19. … We have decided to extend virtual classes, prioritizing student safety and health,” Do Seong-hoon, superintendent of the Incheon Education Office, said.

Nine high schools in Anseong, Gyeonggi Province, also pushed back bringing 12th graders back to school by a day, citing incomplete contact tracing for a virus patient in his 20s in the city, according to the province’s education office.

Most of the approximately 450,000 high school seniors returned to classrooms, five months into the usual academic year, with new health safety guidelines in place such as reduced class sizes, tables physically distanced, temperature checks, and wearing face masks at all times to name a few.

High school seniors were the first group to return due to their tight academic schedule and upcoming college entrance exam, which is one of the most important dates on the calendar, in December.

Other groups of students are to shift to in-person classes in stages through June 8.

Elementary, middle and high school students had shifted to online learning in mid-April due to the coronavirus pandemic.

The confusion surrounding the reopening of schools comes against the backdrop of a rise in the number of new infections in the 24 hours ending 12:01 a.m. on Wednesday.

The number of infected patients rose by 32 on Wednesday, for a total of 11,110, according to the KCDC.

It was the first time in nine days, since the cluster of infections broke out in Seoul’s entertainment district of Itaewon, that the daily infection tally exceeded 30. Daily infection figures had remained below 20.

There were no additional deaths for the third day in a row and the accumulated death toll stayed flat at 273, the KCDC added.

Among the new patients, 24 had contracted the virus in the community -- eight each from Incheon and Gyeonggi Province, six from Seoul, and one each from Daegu and North Jeolla Province. The other eight got it overseas, the KCDC said.

By Kim Bo-gyung (lisakim425@heraldcorp.com)