SEOUL, South Korea >> Health officials in South Korea are expanding booster shots to adults 50 and over as COVID-19 cases creep up again across the country.

The 40,226 new cases reported Wednesday marked the country’s highest daily jump in more than two months, although hospitalizations and deaths remain stable.

Baek Gyeongran, South Korea’s top infectious disease expert, attributed the rising case counts to people’s waning immunities following vaccinations and prior infections and a major removal of social distancing measures since April as the nation wiggled out of an omicron surge. Health workers are also witnessing a “rapid spread” of BA.5, which is seen as the most transmissible variant of omicron yet, Baek said.

South Korea had previously given second booster shots to people who are 60 or older and those with compromised immune systems. Officials are now expanding the eligibility of those shots to people in their 50s and all adults with pre-existing medical conditions. Weeklong quarantines will be maintained for people who test positive.

Officials say the country may see daily case counts of 200,000 by mid-August or September if infections continue to grow. However, they don’t have immediate plans to meaningfully elevate social distancing restrictions, which have been effectively stripped down to an indoor mask mandate over the past months.

Baek, the commissioner of the Korea Disease Control and Prevention Agency, said the government will focus on expanding booster shots and securing larger supplies of antiviral pills to suppress hospitalizations and deaths. She said a return to stringent social distancing will be considered as a last resort, considering the weak economy, but pleaded for people to cancel unnecessary meetings and travel.

“The need to reduce the social and economic damage from social distancing is greater than ever, and we are also considering the economic situation, including inflation and high interest rates,” Baek said. “We also know that people are in a state of accumulated fatigue following lengthy periods of high-level distancing.”

Officials are also stepping up border controls, newly requiring all incoming travelers to undergo PCR laboratory tests on the day of their arrival and quarantine at home until the results come out.

While incoming travelers are currently required to submit negative results of either rapid antigen tests or PCR tests within 48 hours of departure, officials may change the rules to accept only PCR tests — seen as more accurate — if the virus situation worsens, KDCA official Lim Sook-young said.