Korea’s new Covid-19 cases remained above 80,000 for the second straight day. However, despite the rise of the BN.1 mutations, officials said its spread would not be as quick as the BA.5 variant.

Even amid the resurge of new virus cases, the Korea Disease Control and Prevention Agency (KDCA) said it would hold a news briefing next Friday concerning the indoor mask mandate. KDCA added that it would decide whether to lift the mandate based on patient numbers, degree of severity, fatality trend, and its quarantine response capabilities.

According to the KDCA, the country reported 84,571 new Covid-19 infections, down by 2281 from Wednesday. It includes 73 imported cases, bringing the total to 27,925,572.

Korea also added 46 deaths to a total toll of 31,174. In addition, the number of critically ill patients increased to 463.

A comprehensive analysis by the KDCA revealed that the number of new confirmed Covid-19 cases in the first week of December was 58,958 on average, increasing 11.2 percent from the previous week with an infectious reproductive index (Rt) of 1.04, remaining above 1 for eight consecutive weeks.

Also, the incidence rate increased in all age groups, but the increase was especially large in the 10-19-year-olds, followed by the 30-39-year olds, and then the over-80 group, Lim Sook-young, a senior official at the KDCA, explained.

The rate of estimated reinfection cases (as of the last week of November) was 14.7 percent, up from the previous week’s 13.3 percent, showing that one in seven new confirmed cases has been infected twice or more.

"The decrease in immunity obtained through vaccines and infections over time also affect the increase in confirmed cases,” said Lim.

Among the Omicron subvariants, the detection rate of BA.5 and its subvariants (BF.7, BQ.1, BQ.1.1) are still dominant at 71.3 percent, while the detection rate of BN.1 is increasing.

However, Lim explained that although BN.1 is increasing, the speed is quite slow.

Hwang Kyung-won, head of the Covid-19 vaccination response team, added, “Since BN.1 is also an Omicron mutation, we expect that the bivalent vaccine will be sufficiently effective."

According to KDCA statistics, the third vaccination reduces the risk of severe progression by 94.0 percent compared to those who have not been vaccinated.

Also, the rate of severe disease in the non-vaccinated confirmed patients was 16.6 times higher and three times higher than those confirmed patients who received the third and second vaccinations, respectively.

KDCA Commissioner Peck Kyong-ran said, “Vaccination is still an effective quarantine measure, and the completion of the third vaccination is especially important for the elderly and those with underlying diseases.

Winter bivalent vaccines have expanded to four -- Moderna BA.1, Moderna BA.4/5, Pfizer BA.1, and Pfizer BA.4/5.