Most serious pneumococcal infections are caused by Streptococcus pneumoniae (pneumococci) serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F. They commonly colonise the respiratory tract and are spread is via airborne droplets. Primary infection usually results in otitis media (most common) and pneumonia (most serious). Other pneumococcal infections include sinusitis, meningitis, endocarditis, and septic arthritis. Adults with a compromised immune system and the elderly are at high risk.30
There are two pneumococcal vaccines: a conjugated vaccine against 13 serotypes (PCV13) and a polyvalent polysaccharide vaccine against the 23 serotypes (PPSV23). The conjugated vaccine (Prevnar 13) is approved for use in infants and toddlers. The polysaccharide vaccine (Pneumovax 23) is indicated for those ≥65 years old and those between 18-64 years of age with increased susceptibility (Table 8). Persons who received a PPSV23 vaccine prior to age 65 and those at increased susceptibility should be revaccinated 5 years after the first dose.