A protein vaccine composition of protection against pneumococcal infection in a subject is disclosed. The vaccine composition comprises three recombinant pneumococcal neuraminidases: NanA, NanB, and NanC of S. pneumoniae strains CGSP14, wherein administration of the recombinant full-length- and partial-pneumococcal neuraminidases elicits an immune response to all serotypes of S. pneumoniae. In one embodiment, the method further includes a step of adding adjuvants to enhance the immune response. The method also comprises a step of using passive antibodies, wherein said passive antibodies are anti-neuraminidase antibodies generated from neuraminidases-immunized animals against NanA, NanB, and NanC. Meanwhile, this invention also provides a method for the molecular diagnosis of pneumococcal infection, and a method of detecting neuraminidase activity.
