Reaffirming the downward trend of the daily Covid-19 tally, the number of new virus cases fell below 20,000 on Thursday to mark the lowest level in 17 weeks.

The Korea Disease Control and Prevention Agency confirmed 18,816 new virus cases, raising the cumulative caseload to 18,036,720. It was the first time since Jan. 27 that the midweek figure dropped below 20,000 even after health officials resumed full testing after a weekend lull.

However, the death toll came to 24,063, up 34 from the previous day, with a fatality rate of 0.13 percent. Critically ill patients also increased from 232 to 243, according to KDCA.

The health authorities have rolled back most of its virus restrictions amid slowing infections, except for the seven-day self-isolation for Covid-19 patients, which continues until June 20. The government has also eased traveling guidelines, with authorities allowing international travelers to submit supervised rapid antigen test results, issued 24 hours before their departure date, along with PCR test results.

According to the agency, about 44.57 million people have been fully vaccinated, or 86.9 percent of the 52-million population. In addition, about 33.27 million people had received their first booster shots, representing 64.8 percent, and 3.93 million people had their second booster shots.

The nation will hold local elections and parliamentary by-elections next Wednesday to choose the Seoul mayor and Gyeonggi Province governor.

Covid-19 patients will be able to cast their ballot at the same polling stations as uninfected voters after the regular voting session is over.

Meanwhile, health experts raised concerns that North Korea may soon see a surge in Covid-19 cases.

"If the numbers of people with symptoms of fever reported by the North Korean government are indeed Covid-19 patients, there is a possibility that the Covid-19 virus will spread nationwide in the next 30 days," said Kim Shin-gon, a professor at Korea University College of Medicine and Chairman of Unification Health and Medical Association.

Kim questioned the validity of the number of deaths North Korea is currently disclosing.

"The fatality rate of fever cases disclosed by North Korea is 0.002 percent, a low figure difficult to understand," Kim said. "This may estimate the number of confirmed deaths due to Covid-19, or it may be statistical management for quarantine purposes. However, it is unlikely that the number of deaths will increase in the future in an official report."

Kim referred to North Korea’s reporting of no new deaths for the third consecutive day, despite more than 105,000 new suspected Covid-19 cases on Thursday.

North Korea has struggled to contain the Covid-19 virus after reporting its first case on May 12. The isolationist country has since implemented a nationwide lockdown and declared a maximum emergency virus control system.

Professor Kim stressed the need for a humanitarian quarantine support measure for North Korea.

"North Korea is currently very vulnerable to Covid-19 due to the closure of the Sino-Korean border, food shortage, and withdrawal of aid organizations," Kim said.

South Korea needs to find creative ways to cooperate, he added.