A method of providing protection against pneumococcal infection in a subject is disclosed. The method includes steps of administering to the subject a composition that includes combination of three recombinant pneumococcal neuraminidases: NanA, NanB, and NanC of S. pneumoniae strains CGSP14, wherein administration of the recombinant pneumococcal neuraminidases elicits an immune response to S. pneumoniae, and treats the subject. In one embodiment, the method further includes a step of adding adjuvants to enhance the immune response. The method also includes a step of using passive antibodies, wherein said passive antibodies are anti-neuraminidase antibodies generated from neuraminidases-immunized humanized animals: NanA, NanB, and NanC. Meanwhile, this invention also provides a method for the molecular diagnosis of pneumococcal infection.