Pneumococcus, or Streptococcus pneumoniae, the “captain of the men of death” in the parlance of Sir William Osler, has killed millions of people while repeatedly frustrating clinicians, vaccine experts, and epidemiologists. The advent of effective antibiotics did not eliminate deaths from pneumococcal disease. Pneumococcal morbidity has remained substantial among the elderly population even though most have received the 23-valent pneumococcal polysaccharide vaccine (PPSV-23). Diagnostic tests for pneumonia are relatively insensitive and nonspecific.1 Thus, it is difficult to evaluate the efficacy of pneumococcal vaccines against pneumonias that do not lead to detectable bloodstream infection.
Schuchat A. Pneumococcal Prevention Gets Older and Wiser. JAMA Intern Med. 2015;175(12):1897-1898. doi:10.1001/jamainternmed.2015.6133