Stricter measures were enforced in Daegu, with President Moon declaring the hardest-hit area a "special disaster zone", the first time the country had taken such action for a region due to an infectious disease. As a result, the government can provide subsidies of up to 50 percent in restoration costs and exempt residents from taxes and utility payments.

Authorities also banned large gatherings, closed educational institutions and public areas-such as parks, sports facilities and daycare centers-and canceled all major sports events. Nearly all followers of the Shinchonji group, who number about 200,000, have been tested.

Lee Hyuk-min, a professor of laboratory medicine and clinical microbiology at Yonsei University College of Medicine in Seoul, said South Korea had learned many lessons the hard way. For example, it did not have sufficient resources to cope with previous epidemics, notably the outbreak in 2015 of Middle East respiratory syndrome, or MERS. At the time, the KCDC was the only institution authorized to carry out epidemiological testing.

"Testing capacity is not just about getting enough lab kits. It requires years of investment in complex health care infrastructure, including lab hardware and technicians to analyze samples, logistics for moving goods and providing services, and information technology to keep supplies and data moving. Any bottleneck or shortage of these elements can cost time and lead to more infections and deaths," Lee said.

He added that the problem is that "in South Korea, private institutions account for 90 percent of the medical system and 90 percent of our testing capacity," especially laboratories to analyze samples.

After collaborating voluntarily, the public and private sectors must now cooperate more efficiently, he said, and the KCDC should be reorganized to respond more effectively to epidemics, including setting up a branch to specifically supervise testing and diagnose infectious diseases.

"In order for South Korea to carry out all these tests, we have to get all these ducks in a row," he added.

On Monday, the World Health Organization called on all countries to step up their testing programs as the best way to slow the advance of the pandemic. It also urged companies to increase production of vital equipment to overcome acute shortages.

"We have a simple message to all countries-test, test, test," WHO Director-General Tedros Adhanom Ghebreyesus said at a news conference in Geneva, Switzerland. "All countries should be able to test all suspected cases. They cannot fight this pandemic blindfolded."

Without testing, cases cannot be isolated and the chain of infection will not be broken, he said.

Even countries with advanced health systems have struggled to cope with the outbreak, he said, adding that he was deeply concerned about the effects on low-income nations where people are facing malnutrition and other health problems

He added that the strategy to contain the disease-identifying people with infections and rapidly isolating them-is still the best approach, and it has had a positive effect in China, South Korea and Singapore.