One of Korea’s most famous and expensive postpartum centers in Gangnam-gu, Seoul, has reportedly seen a major respiratory syncytial virus (RSV) outbreak.

RSV infection is an acute respiratory infection.

While the infection barely affects healthy adults, it can cause lower respiratory tract infections such as bronchiolitis or pneumonia in infants, immunocompromised people, and the elderly.

According to the Ministry of Health and Welfare (MOHW) on Thursday, five newborns were infected with RSV at a postpartum care center in Gangnam on March 2, with three of them being hospitalized.

At that time, 12 newborn babies were staying at the postpartum center, and quarantine authorities are checking for additional confirmed cases.

According to reports, the center is one of Korea’s most exclusive postpartum centers, with a two-week service for a mother and a newborn costing up to 25 million won ($18,903). The center was used by some of Korea’s top celebrities including Gianna Jun and Kim Hee-seon.

The postpartum center has notified the public health center of the outbreak of RSV group infection and took measures such as  temporary closure.

“We are investigating whether the center violated the Infectious Diseases Control and Prevention Act and the Mother and Child Health Act  but we have confirmed no violations so far,” the ministry said.

Meanwhile, the Ministry of Health and Welfare, along with local governments, is currently conducting regular on-site inspections on hygiene and infection control for all postpartum care centers.

With the investigations set to be completed by this month, the ministry plans to take administrative measures such as corrective orders and fines for postpartum care centers that do not comply with the infection prevention regulations.