South Korea's daily new coronavirus cases fell back below 600 for the first time in six days Monday mainly due to fewer tests over the weekend amid concerns over the fourth wave of the pandemic as the country strives to get more people vaccinated.

The country reported 532 more COVID-19 cases, including 512 local infections, raising the total caseload to 114,646, the Korea Disease Control and Prevention Agency (KDCA) said.

Monday's figure was sharply down from 672 the previous day.

The daily figure hovered above 600 in the past week as people have increased their activities in spring, which could spark another wave of the pandemic.

The country added four more deaths, raising the death toll to 1,801. The fatality rate was 1.57 percent.

Last week, South Korea decided to maintain the current level of social distancing rules through May 2 to contain the virus, while placing more restrictions on entertainment establishments, such as nightclubs and bars.

The greater Seoul area, home to half of the nation's 52 million population, is under the Level 2 distancing scheme, the third highest in the five-phase system. The rest of the country is under Level 1.5, except for some municipalities that have adopted Level 2 measures.

Private gatherings of five or more people are banned nationwide.

From Monday, operations of entertainment establishments are banned in the greater Seoul area and the southeastern port city of Busan.

Since the country started its vaccination program on Feb. 26, a total of 1,517,390 people, or 2.92 percent of the population, have been given COVID-19 vaccine shots, including 4,859 the previous day.

AstraZeneca's vaccine has been administered to 1,000,258 people, while 517,132 received that of Pfizer.

The KDCA said 60,585 people have received two doses.

Starting Monday, the country began administering AstraZeneca vaccines to health care workers for the disabled, seniors and veterans, as well as airline crew members aged 30 or above.

Pharmacists, therapists and dialysis patients will be eligible for the AstraZeneca vaccine beginning next week.

Health authorities are trying to ensure the stable rollout of vaccines, though they may face a hurdle after US and other countries said they are considering giving booster shots to their citizens to better fight COVID-19.

Booster shots refer to an extra jab of a vaccine after full inoculation to bolster a person's immune system.

Vaccine suppliers, like Moderna and Pfizer, have said booster shots may be necessary amid the global race to secure enough vaccines.

South Korea said earlier that it has secured vaccines for 79 million people. The country plans to vaccinate 12 million people by the end of June and achieve herd immunity by November.

A total of 12,229 cases of side effects after vaccinations have been reported, up 38 from a day earlier, but 98.4 percent were mild symptoms, including muscle pain and fever.

A total of 46 deaths after vaccinations have been confirmed, according to the KDCA, up two from the previous day. Authorities, however, said the exact causes of the deaths remain unknown.

Of the newly confirmed locally transmitted cases, 288 cases came from the capital area, with 136 from Seoul, 142 from Gyeonggi Province and 10 from Incheon, 40 kilometers west of the capital.

The southern port city of Busan, the country's second-largest city, reported 25 more cases.

There were 20 additional imported cases, down three from a day earlier. The country's total number of imported cases is now at 8,002.

Health authorities are especially keeping close tabs on COVID-19 variants from overseas that are believed to be more contagious. On Sunday, they confirmed nine cases of the Indian variant, in addition to COVID-19 variants from Britain, South Africa and Brazil.

The number of seriously or critically ill COVID-19 patients was 99, down three from the previous day.

The total number of people released from quarantine after making full recoveries was 104,474, up 468 from a day earlier, with 8,371 people being isolated for COVID-19 treatment, up 60 from a day ago.

South Korea has carried out 8,414,821 COVID-19 tests, including 18,755 the previous day. (Yonhap)