SEOUL — The biggest mission for Jo Yong-seok this week has been to keep the coronavirus out of his Seoul home, where his 18-year-old son is studying 15 hours a day for the most important exam of his lifetime.

On Thursday, nearly half a million students are taking the annual College Scholastic Ability Test. Known as Suneung in Korean, it’s a multiple-choice standardized test similar to the SAT but with considerably higher stakes in education-obsessed South Korea.

The eight-hour exam determines not only which university the younger Jo can attend, but also his future career opportunities, social standing and even marriage prospects. Students spend days and long evenings at expensive private cram schools preparing for the hypercompetitive exam.

Only this time, there was a pandemic.

South Korea is struggling to contain a third wave of the novel coronavirus. The elder Jo, determined not to infect his son, has avoided seeing friends and gave up his favorite pastime of hiking. He even offered to forgo family meals and dine separately until the day of his son’s exam.

“My son has been studying all these years for this one day,” he said. “I can’t let the virus ruin it.”

In what she called a “desperate plea” a week before the exam, the country’s education minister, Yoo Eun-hae, urged the public to “entirely suspend everyday social activities” to tamp down infections.

That day, South Korea reported 583 new coronavirus infections, the biggest one-day jump in eight months, with another 540 cases reported on the day of the exam.

Even during the pre-pandemic times, Suneung proctors supervising the exams were banned from wearing perfume or high heels, in case strong fragrances or the click-clack sound disturb students’ concentration.

This year, some will be asked to don full protective gear to supervise the exam for at least 35 confirmed covid-19 patients and some 400 students in quarantine. For this group, test papers are put in plastic bags and disinfected before grading.

“We pushed the beds out and brought the desks in,” said Yoon Jae-sik, spokesman for the Seoul Medical Center, where five covid-19 patients are taking the test in a “negative pressure ward” designed to keep infectious germs from spreading outside.

“It’s a rather unusual setting, but the patients are taking the exam in a calm manner,” he said.

At test venues, plastic dividers have been set up to separate desks, and students are required to wear masks at all times.

In previous years, Suneung exam mornings kicked off with the sound of younger students cheering for their seniors as they walked into the test center. That ritual has been banned this year, for fear of spreading the coronavirus, and replaced with temperature checks.

Yang Hee-yeon, 19, who is retaking the exam in an attempt to improve her score, said the new rules made her worried about wasting a year’s work.

“Last year’s Suneung, even without the masks and plastic shields, was nerve-racking on its own,” Yang said. “My future depends on this test. Every little change in the surroundings gives me the jitters.”

On a typical Suneung day, South Korea falls into silence in case noise disturbs the students, with air traffic grounded and military exercises suspended.

To make sure no student is late for the exam, many companies delay their start time so that roads are clear in the morning. Even the stock market opens an hour late.

This year's exams have been postponed by two weeks due to virus-led disruptions in the academic calendar.

Cho Min-jun, a high school senior applying to study sociology, says the postponement allowed more time to cram, but it also added to the pressure. But he didn’t mind having to wear a mask during the back-to-back exams, as he is used to studying in one.

“However, the masks will come off during the lunch hours as we eat our packed lunch, which gets me worried,” he said.

For exam day, Cho said he is bringing a lunchbox of his comfort food — bean sprouts and an omelet — and plans to stay strictly behind a plastic shield while eating it.

South Korean President Moon Jae-in urged “vigilance until the last-minute” of the test, because coronavirus risks are high with many people gathered in closed indoor spaces all day long.

In April, South Korea was one of the first countries to stage national parliamentary elections in the midst of the pandemic, an exercise that was deemed a “national success” as no new cases were linked to the vote. But Moon said tensions were even higher now.

Health authorities say students are not off the hook even after they leave the test centers at the end of the long day. Officials have issued stern warnings against young people going out to unwind after their exhausting endeavors, in case it aggravates spread of the virus.

Cho said there were many places he planned to explore after his exams, such as art exhibitions he had missed.

“But now, it seems those fun times will not happen until much later,” he said. “After the exams, I just want to stay at home and catch up on lost sleep.”