Beyfortus and Enflonsia, the RSV preventive antibodies available for infants in Korea, directly supply antibodies to lower the risk of lower respiratory tract disease rather than working like conventional vaccines. Both cover newborns and infants entering their first RSV season, but only Beyfortus is approved in Korea for high-risk children up to 24 months old during a second season. Enflonsia may cause false negatives in some rapid-antigen tests, so clinicians should be told about prior administration. If infection remains suspected despite a negative result, a clinician may consider molecular testing. Selection should reflect age, birth timing, underlying conditions and previous preventive treatment.