Although the decline of new Covid-19 cases stagnated over the weekend, quarantine officials predicted on Monday that there would be no sudden increase for the time being.

"The decline in the Covid-19 prevalence is slowing down," said Son Young-rae, head of the social strategy team in the Central Disaster Management Headquarters. "However, it remains to be seen whether such trends will continue this week."

According to the Korea Disease Control and Prevention Agency (KDCA), Korea saw 20,601 new virus cases on Monday, raising the cumulative caseload to 17,564,999. As a result, the cumulative death toll came to 23,400, up 40 from the previous day, with a fatality rate of 0.13 percent. However, critically ill patients came to 421, down two from a day earlier.

The stagnant decline in daily cases follows Korea lifting the outdoor mask mandate last Monday except for large gatherings of 50 or more.

Son emphasized that while it is necessary to keep an eye on the situation, the previous Covid-19 spread and the minor surge after the latest Omicron wave should be viewed differently.

"During the several Covid-19 waves last year, the government suppressed the spread of the virus by strengthening social distancing rules," Son said. "However, amid the latest Omicron wave, the decline began naturally as the nation achieved considerable immunity due to many infections amid eased distancing rules."

The government does not regard the current situation as one where the downtrend will stop, he added.

Son noted that the government expects a small number of infections to occur among uninfected people.

In contrast to the government's relative optimism, experts continued to express concerns about the global rise in Omicron subvariant cases.

For instance, the New York State health officials said that BA.2.12 and BA.2.12.1, the subvariants of the BA.2 variant, also known as stealth Omicron, are spreading rapidly in the state.

Together the two new variants comprise about 90 percent of cases in central New York.

Korea also confirmed its first case of the BA.2.12.1 mutation last month.

According to the Central Disaster and Safety Countermeasures Headquarters (CDSCH), the person infected with the BA.2.12.1 mutation is a woman who arrived from the U.S. on April 16 and tested positive for the strain the following day.

The 50-something woman has completed the third dose of her vaccination. However, the health authorities noted that the patient had not experienced any clinically unusual circumstances.

The quarantine authorities also identified 16 people who had contacted the patient and investigated them.

According to health officials, while the stealth Omicron variant has about 30 percent higher propagation power than the existing Omicron, the BA.2.12.1 is estimated to show a 23-27 percent faster detection increase rate than the stealth Omicron.

The Joe Biden administration has warned that up to 100 million Americans could be infected during a potentially significant wave of Covid-19 in the U.S. this fall and winter.

As a result, the U.S. government has been trying to receive approval for new funding for vaccines and tests from Congress.

Korean health experts have also warned of a possible resurgence of the virus in Korea in the fall or winter.

Experts have been calling the government for preemptive preparations for Covid-19's resurge in autumn.

Lee Jae-gap, a professor of infectious disease at Hallym University Gangnam Sacred Heart Hospital, most recently stressed the need for Korea to prepare for the possible resurge of Covid-19 this autumn or winter on May 3.

"Come fall and winter, and the nation may face a situation where various respiratory viruses, including Covid-19, influenza, RSV virus, and rhinovirus, are prevalent simultaneously," Professor Lee said. "Hospitals will have to consider seriously conducting not only Covid-19 virus test other respiratory virus tests when patients visit the respiratory clinic."

He then stressed the need to introduce the multiplex PCR (polymerase chain reaction) testing method at respiratory clinics. He proposed introducing an infection prevention management fee for respiratory infectious disease due to the phase-out of face-to-face Covid-19 treatment fees.

Lee also explained that it is crucial to continue vaccinating 5-to-11-year olds and provide second booster shots for adults 60 or older.

Lee noted that the problem is it is not easy to predict whether the Omicron's subvariants will continue to appear, leading to the repetition of small waves or a new variant occurring to replace the Omicron.

Therefore, he stressed that the nation needs to prepare for each scenario.

President-elect Yoon Suk-yeol, who will take office from midnight Tuesday, had stressed that the new government is planning to start a public awareness survey and reorganization of quarantine guidelines from next month, and prepare a draft guideline revision and reorganization of the social distancing rules in August, to prepare for the possible resurgence of the virus in the fall.

As of Monday, 33.18 million people have received booster shots, or 64.7 percent of the country's population. The number of fully vaccinated people also came to 44.56 million, representing 86.8 percent of Koreans, the KDCA said.