39 new COVID-19 cases were confirmed in South Korea on Thursday, the fewest daily total since late February.
23 came from recent overseas arrivals while the remaining 16 cases were from local transmissions.
The national death toll stands at 204 with 4 more fatalities reported on Thursday.
109 of the 204 victims had contracted the virus at welfare facilities or hospitals.
And, more than a quarter of all those infected in nursing hospitals have died, displaying a higher fatality rate among elders.
For patients older than 80, the fatality rate stands at 21.14 percent compared to the national average of 1.96 percent.
The head of Central Disease Control and Prevention Headquarters, Jung Eun-kyeong, said that health authorities have continuously monitored the virus' genetic sequence. But, have been unable to find any meaningful genetic variants that could influence the power of transmission or the virus' ability to cause disease.
She also said that the plasma treatment guidelines will be announced soon.
"We are almost done with guidelines for extracting blood plasma. Now we are gathering opinions from experts on how to apply this treatment and to which patients this treatment could be applied to We will announce the guidelines as soon as we are ready."
The treatment involves taking blood plasma from recovered COVID-19 patients, and infusing it into current patients' blood so that the antibodies can fight the virus.
Hong Yoo, Arirang News.