BA.2, the subvariant of the Omicron strain often called the “stealth variant,” is spreading rapidly in Korea, too.

An expert said BA.2 would emerge as the dominant strain in Korea next week and continue to be so for the following 10-14 weeks before giving its status to yet another variant.

Cheong Jae-hoon, a preventive medicine professor at Gachon University College of Medicine, predicted in his presentation, “The future of Covid-19, transition to endemicity,” at an academic conference organized by the Korean Vaccine Society on Friday.

“BA.2 will soon become a dominant variant and continue to maintain the status for between 10 and 14 weeks,” Professor Cheong said. “After the period is over, another variant will come and continue to dominate the pandemic situation.”t

According to the Central Disease Control Headquarters, the detection rate of BA.2 surged to 41.4 percent on Monday, up 15.1 percentage points from the previous week’s 26.3 percent. In addition, the detection rate recorded a four-fold jump from 10.3 percent a month ago. If the current trend continues, the comparable rate will rise above 50 percent in the fourth week of March.

BA.2 has already become a dominant strain in other countries.

Over the past few weeks, the stealth Omicron has spread worldwide, including China and Europe. According to the U.S. Center for Disease Control and Prevention (CDC), 23.1 percent of new Covid-19s cases in America were infected by BA.2 during the week ending March 12.

BA.2 has stronger contagious power than the Omicron variant (BA.1) but shows little difference in severity and hospitalization rates. The current diagnostic kits can also confirm it.

“There are times when two virus variants make transitions,” Cheong said. “In other words, when two variants compete, there is a moment when the two take shares in 50-50 ratio around when the transition occurs.”

Given the current transition from BA.1 to BA.2, the latter’s dominant period will likely be 14 weeks, he added.

“The transition will likely occur next week. That means a time bomb begins to tick from then,” Cheong said. “Therefore, it is critical what policies the government will take to respond to the situation for about three months.”

Commenting on the characteristics of the emerging variant, the preventive medicine experts said, “Of course, the transmission power will be stronger while vaccine’s effects will be weakened. It is yet to be seen in which direction the severity rate will move. However, given many cumulative infections and high vaccination rate, the share of severely ill patients is unlikely to rise high even when another virus wave comes.”

Emphasizing that the next virus variant will come in ways to reduce immunity or vaccination effects, Cheong advised the government to think about revising its vaccination policy to meet the new situation.

Professor Cheong stressed that future quarantine policy should comprise both pharmaceutical and non-pharmaceutical intervention, explaining that the former is to reduce or remove damage and the latter is to postpone the arrival of damage.

Commenting on pharmaceutical intervention, he said, “It will be most important to predict the vaccination scope, targets, and timing to respond to the future spread. Besides, the government should secure sufficient oral Covid-19 treatments and maintain the medical and diagnostic system to increase their administration.”

As to the non-pharmaceutical intervention, he noted that the government needs to worry about how long it should maintain the mask mandate while thoroughly analyzing the effects of the social distancing system.

Noting that the social distancing produced clear effects and accompanied social costs, he advised the officials to evaluate such costs and benefits objectively and put the results to public debate.

Commenting on the recent government move to adjust the infectious disease grade of Covid-19 or treat it like the seasonal flu, Professor Cheong said, “Whether or not the government changes the grade of Covid-19, the pandemic will not change its form. Provided that the situation is ripe, it may change the grade. However, the government does not need to hurry to change the grade, make unnecessary preparations, and add administrative burdens.”