Pfizer’s Abrysvo approved in Korea…sparks competition

Receives MFDS approval on the 13th…Korea’s first RSV vaccine given during pregnancy for infants to be introduced in Korea

Pfizer Korea’s respiratory syncytial virus (RSV) vaccine ‘Abrysvo Inj’ has received approval from the Ministry of Food and Drug Safety (MFDS), completing a competitive lineup spanning both adult and infant RSV prevention in Korea.

The MFDS granted marketing authorization for Abrysvo on Aug. 13. With this approval, the competition in South Korea's RSV prevention market is expected to intensify further, featuring a three-way battle for adult vaccines, alongside a showdown between preventive monoclonal antibody injections and maternal vaccines for infants and young children.

The adult RSV vaccine market has become a three-way race, with Pfizer’s Abrysvo joining GSK and Moderna, which had already established a presence in the market.

GSK’s ‘Arexvy,’ the first to enter the market, recently expanded its indication to include high-risk adults aged 18 to 49. The company has strengthened its market position with data from the Phase III AReSVi-006 trial and long-term follow-up studies, demonstrating 94.6% efficacy in people with underlying medical conditions and sustained protection over three RSV seasons.

Moderna is also competing with its mRNA-based mRESVIA, approved for adults aged 60 and older. The company is seeking to expand the indication to younger high-risk adults, leveraging the mRNA technology validated through its COVID-19 vaccine.

Pfizer’s newly approved Abrysvo secured indications not only for adults aged 60 and older but also for high-risk adults aged 18 to 59, positioning it as a strong competitor in the adult market.

The infant RSV prevention market, meanwhile, is developing a distinct competitive landscape involving two strategies that differ in both timing and method of administration.

Until now, infant RSV prevention has been led by monoclonal antibody injections administered directly to infants after birth. Sanofi's ‘Beyfortus’ opened the market as a long-acting antibody injection providing five months of protection with a single dose. It was followed by MSD's ‘Enflonsia,’ which entered the market emphasizing the convenience of a single fixed 105 mg dose regardless of body weight.

Pfizer’s Abrysvo, by contrast, introduces Korea’s first maternal immunization strategy. The vaccine is administered to pregnant women between 28 and 36 weeks of gestation, allowing antibodies generated in the mother to be transferred to the fetus through the placenta. According to the Phase III MATISSE trial, maternal vaccination with Abrysvo reduced the risk of severe RSV lower respiratory tract disease in infants by 81.8% through 90 days after birth.

In the field, physicians expect the two approaches, direct antibody administration to infants after birth (Beyfortus or Enflonsia), and maternal vaccination during pregnancy (Abrysvo), to provide immunity from birth and to be used complementarily depending on factors such as maternal vaccination status, timing of birth and the infant’s risk of severe disease.

While prevention options have expanded, calls are growing on the need for the government’s financial support to facilitate broader uptake in clinical practice.

RSV can progress to severe lower respiratory tract disease, including bronchiolitis and pneumonia, particularly in infants and older adults. According to Korea’s National Health Insurance claims data, 44.7% of children under age 5 with RSV required hospitalization, while infants aged 6 to 11 months accounted for 57.3% of RSV patients admitted to intensive care units, underscoring the substantial disease burden.

Given the nature of government health policy, discussions on public support for RSV prevention are likely to prioritize infants before older adults. However, the appropriate policy framework has yet to be established.

Preventive antibody injections such as Sanofi’s Beyfortus and MSD’s Enflonsia are intended to prevent infection but are classified as ‘monoclonal antibody drugs’ rather than ‘conventional vaccines.’ Therefore, their coverage, whether they should be supplied through the National Immunization Program (NIP) or prescribed with reimbursement through National Health Insurance, is being reviewed. With the approval of Abrysvo adding a maternal immunization vaccine to the available options, policy discussions over infant RSV prevention are expected to materialize further.

An industry official said, “RSV is one of the leading causes of hospitalization among infants and young children, but due to its non-reimbursement, there had been an urgent need for government support. Now that multiple preventive options are available, the pace of discussions over NIP inclusion and reimbursement serves as a key factor determining the future of Korea’s RSV market.”