A pneumococcal vaccine is a vaccine against Streptococcus pneumoniae. More at Wikipedia
Pneumonia - Pneumonia is an inflammatory condition of the lung.
Streptococcus pneumoniae - Streptococcus pneumoniae, or pneumococcus, is gram-positive, alpha-hemolytic, bile soluble aerotolerant anaerobe and a member of the genus Streptococcus.