Provided is an antigen including a recombinant respiratory syncytial virus (RSV) F protein, wherein the recombinant RSV F protein includes an antigenic region flanked with an HRN region and an HRC region, and the antigenic region includes one or more antigenic sites selected from the group consisting of site Ø, site II, and site IV. The present disclosure also provides a nucleic acid molecule encoding the antigen and a vaccine composition including the antigen for eliciting an immune response against RSV