In this study the humoral and cellular immune response after vaccination with Prevnar 13 will be measured in patients who have had CAP with S. pneumoniae. The patients will be recruited from the Ovidius and Triple-P study, two consecutive clinical trials initiated by the St. Antonius Hospital Nieuwegein.(6,7) Patients who survived pneumococcal pneumonia are considered as a high-risk population for pneumococcal disease in the future.(8) Possibly these patients have less response to pneumococcal vaccination because of an impaired immune response against S. pneumoniae. Special interest goes to vaccination responses in the subgroup of pneumococcal pneumonia patients without a culture matching specific antibody response in order to investigate if this reflects the failure to elicit an immune response during pneumonia found by Van Mens et al.