Streptococcus
pneumoniae

Streptococcus pneumoniae can be found in the upper respiratory tract of healthy individuals; however, like some bacteria that make up normal human flora, it can become pathogenic to those more susceptible.  The elderly, children under 2 years old, children in daycare, and persons with underlying medical conditions like HIV infection or sickle-cell disease represent some of the population at higher risk for infection. 

S. pneumoniae is spread from person to person through respiratory droplets that are often released through sneezing and coughing by individuals who carry the bacteria in their nasopharynx.  Occasionally, S. pneumoniae can enter sterile sites within the body and cause invasive disease. Thus, despite its name, S. pneumoniae is responsible for other types of infections besides pneumonia, including but not exclusive to bacteremia, otitis media, meningitis, sinusitis, peritonitis and arthritis. 

Vaccinations against invasive pneumococcal disease have been available in the United States since 1977 and are continuing to develop as a way to prevent serious S. pneumoniae infection.  Currently available vaccines include the 23-valent pneumococcal polysaccharide vaccine (PPSV23) and the pediatric 7-valent pneumococcal conjugate vaccine (PCV7). Additional vaccines information can be found on the CDC PPSV23 and PCV7 Vaccine Statement pages.

For more information please visit the CDC Streptococcus pneumoniae Disease website

Image courtesy of the CDC Public Health Image Library

Maryland Emerging Infections Program/ABCs
Johns Hopkins University Bloomberg School of Public Health
Candler Building
111 Market Place, Suite 850, Room 8546
Baltimore, MD 21202
Phone: 410-223-1810
Fax:  410-223-1815
Email: mdabcs@jhsph.edu