South Korea plans to mass-produce an antibody-based therapy for COVID-19 later this month, health authorities said Tuesday.

The Ministry of Food and Drug Safety is currently reviewing plans for Phase 2 and Phase 3 clinical trials of the antibody-based treatment, and a large quantity of commercial coronavirus antibodies will be produced this month, said Kwon Jun-wook, deputy director at the Korea Centers for Disease Control and Prevention.

The Phase 1 trials were approved in July, he added. 

Antibody therapies are designed to mimic the body’s natural response to an invading virus and disable the threat. They are seen as a promising way of treating COVID-19 when a vaccine may still be months away.

The antibody treatment also gained approval in the United Kingdom on July 29, with Phase 1 clinical trials underway, Kwon added.

For blood plasma-based treatment, which takes plasma from a recovered person and infuses it into another COVID-19 patient, he said the Drug Ministry approved a Phase 2 study on Aug. 20. Its safety and effectiveness are being assessed at six medical institutions.

The supply of the blood plasma for the Phase 2 trial will be completed in mid-October, he said.

Korea’s daily count of new COVID-19 cases stayed below 200 for the sixth consecutive day on Tuesday, though health authorities are on alert over untraceable cases and sporadic outbreaks.

Korea reported 136 new COVID-19 cases Tuesday -- 120 locally transmitted and 16 imported -- bringing the total caseload to 21,432, according to the KCDC.

With tightened social distancing rules in place nationwide, Korea appears to be entering a stabilizing phase in its fight against the coronavirus. After reaching a peak of 441 on Aug. 27, the daily tally has gradually decreased.

Though the number of cases is declining rather slowly, Kwon said there are many “thankful” signs suggesting that the country will see a “definite slowdown in COVID-19 infections this week.”

He said the explosive spike has stopped, many municipalities report no new COVID-19 cases, the Greater Seoul area posted double-digit case numbers for two days straight and the pace of increase in the number of critically ill patients slowed.

Sohn Young-rae, a senior official from the Health and Welfare Ministry, said a decision on whether to end or extend the current level of social distancing will be made at the end of this week.

The government announced on Friday its decision to extend its toughened social distancing guidelines for another week since there was no definite slowdown in the infection rate.

Level 2.5 social distancing rules, which were to end Sunday, are in place until Sept. 13 in the Greater Seoul area -- home to nearly half of the country’s population. Level 2 social distancing rules were extended across the country until Sept. 20.

Korea has consistently posted triple-digit rises since Aug. 14 due to outbreaks tied to churches and an anti-government rally in central Seoul on Aug. 15.

Cases traced to the Sarang Jeil Church and the massive rally rose to 1,167 and 539, respectively, as of Tuesday at noon. As of Monday, COVID-19 testing was completed for 86 percent of those tied to the Seoul-based church and 79 percent of those linked to the rally.

New clusters of infections were reported in connection with a call center, religious facilities, a kindergarten, a hiking gathering and a sales event.

Transmission routes were unidentified for 22.4 percent of the new cases reported from Aug. 26-Sept. 8, according to the KCDC, which could mean the virus is spreading silently.

As crowds flock to the parks amid stricter social distancing rules in place in the Seoul metropolitan area, the Seoul Metropolitan Government restricted access to crowded areas in three of the most sought-after Han River parks in Seoul -- Yeouido, Ttukseom and Banpo Han River parks -- starting at 2 p.m. Tuesday. In all 11 Han River parks across the capital, the operation of cafes, convenience stores and parking lots is only allowed until 9 p.m.

The number of visitors to the Han River parks increased by up to 40 percent in the first week of September, compared with the same period last year, according to the city government.

Of Tuesday’s locally transmitted cases, the vast majority were still registered in the Seoul metropolitan area -- 67 in Seoul, two in neighboring Incheon and 29 in Gyeonggi Province, which surrounds the capital.

The greater Seoul area has posted fewer than 100 new COVID-19 cases for the second consecutive day.

Outside the Seoul metropolitan area, COVID-19 cases were reported from only six administrative cities and provinces -- 12 cases in Gwangju, four cases in Daejeon, three cases in Ulsan, two cases in Incheon and one case each in Busan, Sejong and North Chungcheong Province.

Of the 16 imported cases, 12 were identified while the individuals were under mandatory self-quarantine in Korea, with the other four detected during the quarantine screening process at the border. Some 11 came from Asia, four from Europe and one from Africa. Eight of the newly diagnosed people were foreign nationals.

The number of COVID-19 patients in serious or critical condition was 151 as of midnight Tuesday, with most of them in their 60s or over. This marks a 17-fold increase from only nine people on Aug. 18. 

 Five more people died of the coronavirus in a single day, bringing the death toll to 341. The overall fatality rate amounted to 1.59 percent.

So far, 16,636 people, or 76.62 percent, have been released from quarantine upon making full recoveries, up 339 from a day earlier. Some 4,455 people are receiving medical treatment under quarantine.

The country has carried out 2,066,078 tests since Jan. 3, with 43,370 people awaiting results as of Tuesday.

(laeticia.ock@heraldcorp.com)