Prevention Capsular Polysaccharide Vaccine The pneumococcal capsular polysaccharide vaccine administered to adults since the early 1980s contains 25 µg per dose of capsular polysaccharide from each of the 23 most prevalent serotypes of S. pneumoniae. Vaccination stimulates antibody to most serotypes in most recipients. One case-control study showed a protection rate of 85% lasting ≥5 years in adults