South Korea saw its daily addition of cases stay in the 400s on Sunday, as the country continues its fight against the third COVID-19 wave with its vaccination campaign.

While the virus situation seems to be better controlled than weeks earlier, authorities remain cautious over a potential uptick in virus cases. The number of new cases could rise at any time due to an increased number of travelers during warmer weather, they warn.

The country added 416 new cases Sunday -- 399 locally transmitted and 17 imported from overseas -- raising the accumulated total to 92,471, according to the Korea Disease Control and Prevention Agency. The latest addition is slightly down from 418 cases reported a day earlier.

The country also added two more deaths from the virus, raising the total to 1,634. The number of COVID-19 patients in serious or critical condition sat at 134, down from 136 people a day earlier. The country conducted 42,313 tests Saturday, down from 62,636 checks done Friday.

Out of 17 new cases uncovered from overseas arrivals, patients from Asian countries other than China accounted for nine, followed by the United States with five, Europe with two and Africa with one.

The country has been requiring all arrivals to submit negative results of polymerase chain reaction tests when entering Korea. Foreign travelers without the test results are denied entry, as Korea also faces worries of an influx of COVID-19 variants from overseas.

“As more people travel in the spring and COVID-19 situation prolongs, there is a chance for COVID-19 to gain force again from increased social fatigue and loosened adherence to virus rules with the launch of the vaccination campaign,” senior Health Ministry official Yoon Tae-ho said in a press briefing Sunday.

“Virus variants are also active in many countries around the world, and we are also in danger of mutated viruses creeping in and spreading. This is what many experts worry of, too.”

More than 80 percent of the new local cases were found in the Greater Seoul area that includes Incheon and Gyeonggi Province, accounting for 323 out of 399 new cases. Seoul had 127 cases, while Gyeonggi Province and Incheon reported 169 and 27 cases, respectively.

Private gatherings accounted for dozens of new cases, and small cluster infections were reported from a number of multiuser facilities. Dongducheon, Gyeonggi Province, has reported a total of 132 cases so far from testing all foreign residents there.

The capital region at the moment is under Level 2 social distancing rules while the rest of the country remains at Level 1.5. An additional ban on private gatherings of five or more people placed since December is still in place.

The country is looking to adopt a new four-tier social distancing scheme that would allow most businesses to stay in business while following virus control measures. The new system is planned to go live by the end of this month.

And to overcome the pandemic within this year, Korea has been running a nationwide COVID-19 vaccination campaign initially with doses obtained from overseas drugmakers. Authorities aim to achieve herd immunity by November with vaccines they obtained through deals signed with foreign firms.

The country as of the end of Saturday had administered COVID-19 vaccines to 314,656 people, with 17,131 of them done in the last 24 hours. Vaccines from AstraZeneca were given to 309,387 people, and the rest were given vaccines from Pfizer and BioNTech.

Both vaccines need to be administered twice for full protection. Only the first round of vaccinations is underway at the moment. Second shots will be available eight weeks later for those given vaccines from AstraZeneca and after three weeks for those given doses made by Pfizer.

Korea has so far reported a total of 3,689 cases of adverse symptoms from those who were administered the vaccines, 806 of them added throughout Saturday. A total of nine have died after taking the vaccines, though it has not been verified whether the vaccines played a role in their deaths.

Health authorities said Sunday that no correlation between vaccination and cases of fatalities had been found so far.

And to uncover more potentially hidden cases, authorities have been promoting a new privacy protection measure that allows people to use encrypted private numbers instead of their real phone numbers when registering information upon entering locations such as restaurants. The system encrypts the phone number with a system using a QR code, which allows only authorities to access the real phone number, should it be required.

Prime Minister Chung Sye-kyun said in a meeting Sunday that the government will scale up to process up to 500,000 COVID-19 checks a day, as opposed to the current cap of 230,000.

By Ko Jun-tae (ko.juntae@heraldcorp.com)