South Korea conducted more than 15,000 tests yesterday as health officials raced to contain an outbreak of Covid-19 linked to at least nine clubs in the nightlife district of Itaewon in Seoul.
The promise of anonymous testing has encouraged more people to come forward, as the number of cases linked to the new cluster grew to 119 - up from 102 the previous day.
New cases included a 27-year-old clubber from Busan who infected his 62-year-old father and one-year-old nephew. Eleven infections were traced to a 25-year-old private academy teacher from Incheon and three more infections in the military brought infections in the armed forces linked to the Itaewon cluster to 11.
South Korea now has 10,962 cases, with 259 deaths.
The Itaewon cluster came to light when a 29-year-old resident of Yongin city tested positive last Wednesday, after visiting five gay clubs in Itaewon on May 1-2 during a six-day long weekend that saw many people going out to wine, dine and party.
With the number of secondary infections reaching 43, officials warn that a delay in diagnosis could "exacerbate the damage".
About 700 out of the 5,517 people who visited the five clubs identified in the cluster - all known to be gay bars - remain uncontactable.
Even so, there are no immediate plans to resume stringent social distancing rules that were eased from last Wednesday.
But there are new precautionary measures in place, such as requiring people using the subway during peak hours to wear face masks from yesterday.
Air-conditioned public buses also started running with windows open for better ventilation.
Vice-Health Minister Kim Gang-lip said that the authorities would not reinstate the tougher rules if the number of new cases daily remained below 50 and if 95 per cent of the cases could be traced.
A total of 26 new cases were reported yesterday, out of which 22 were local transmissions.
The highest number of cases in the past week was 35, on Monday.
Ms Jung Eun-kyeong, director-general of the Korea Centres for Disease Control and Prevention, warned that the numbers would rise due to extensive contact tracing and voluntary testing.
But it was too early to compare the Itaewon cluster to the February outbreak linked to the Shincheonji Church of Jesus, she added.
More than 5,000 infections to date have been traced to Shincheonji, whose 200,000 members underwent testing at the peak of the outbreak.
This time round, some 22,000 tests had already been conducted on people, including 1,200 foreigners, potentially exposed to the Itaewon cluster.
Itaewon is popular with foreigners and many live in the area.
Nine clubs have been named as potential hot spots. The first five are King Club, Queen, Trunk, Soho and HIM, all of which the first patient in the cluster visited.
The second batch comprises Club Made, Pistil, Pink Elephant and Fountain - all of which the first patient did not visit.
The Yongsan District Office, which oversees Itaewon, said it is collecting the list of visitors at each of the four clubs for contact tracing.
Incheon city is also on high alert for mass infections, after a 25-year-old teacher and resident was found to have infected at least 11 people after visiting King Club on May 2-3.
Those infected included five high school students at the academy where he taught, a colleague and an acquaintance.
He also infected a middle school student whom he tutored privately, as well as the student's mother and twin brother, and the brother's tutor.
Over 1,000 members of two churches that some of the students attended have been told to get tested and to stay at home.
Incheon has also imposed a one-week ban on the operation of all private academies in the city.
Incheon Mayor Park Nam-chun said: "It will be tough to maintain social distancing that has been in place since February, but parents need to refrain from sending their kids out to these private academies. We will do our best to make sure no single contact is missed out."
