Although the Covid-19 resurgence has turned to a decreasing trend, health authorities expressed concerns on Tuesday that the number of severe cases and deaths will continue to increase until the beginning of next month.

According to health officials, the Covid-19 infection reproduction index (R0), which was 1.06 in the third week of August, fell to 0.98 in the fourth week.

It was the first time in nine weeks since the fourth week of June that the infection reproduction index fell below 1. The reproduction index shows the average number of people a patient can transmit the virus. If the index rises above 1, it is difficult for epidemiological investigations or quarantine responses to keep up with the spread of the virus.

"Most experts believe that the peak of the ongoing wave came at the third week of August," said Im Sook-young, a senior official at the Central Disease Control Headquarters. "The government expects the trend to decrease for the time being."

The number of confirmed cases in the fourth week of August totaled 769,552, down 13.8 percent from the third week’s 893,093. The average number of confirmed cases per week also fell from 127,585 in the third week to 109,936 in the fourth week.

Although the daily average number of confirmed cases decreased in all age groups, health officials have been worried about the growing share of Covid-19 patients in high-risk groups over 60 years of age.

"The number of severe cases and deaths that appear with a lag of two to three weeks after infection may stagnate or increase for the time being," Im said.

The health agency projected the numbers of critically ill patients and Covid-19 deaths could reach 800 to 900 and 60 to 70, respectively, in early September.

In addition, the ratio of re-infection in total confirmed cases has exceeded 7 percent, with the cumulative number of re-infected people exceeding 300,000.

Reinfection occurs more frequently among children, adolescents, and young adults.

By age, those aged 0-17 had the most reinfection cases with 40.7 percent, followed by 18-29 years old at 17 percent, 30-39 years old at 13 percent, and 40s at 10.7 percent.

Among people who tested positive for the virus three times, those aged 0-17 accounted for 30.6 percent, 18-29 years old 22.2 percent, and 30-39 years old 12.2 percent of the cases.

The government will hold a meeting of the Central Disaster and Safety Countermeasures Headquarters on Wednesday to announce the policy related to pre-entry Covid-19 testing and the direction of the winter vaccination plan.

An advisory panel of private experts to the Prime Minister's Office had recommended the government scrap the pre-entry test requirement on Monday, replacing them with post-arrival tests.

The winter vaccination plan will include updated vaccines that can respond to Omicron variants.

On Tuesday, Korea added 115,638 new Covid-19 infections, including 380 from overseas, bringing the total caseload to 23,142,479, the KDCA said.

The country reported 71 new Covid-19 deaths, bringing the death toll to 26,689, the KDCA said. The fatality rate stood at 0.12 percent. The number of critically ill patients remained high at 591, slightly down from the four-month high of 597 reported Monday.

According to the KDCA, about 44.66 million among 52 million Koreans have been fully vaccinated. In addition, about 33.55 million people had received their first booster shots, and 7.13 million had their second booster shots.