People whose immune systems are weakened are more susceptible to pneumococcal infection than their healthy counterparts. Because our immune systems weaken with age, vaccination against S. pneumoniae is recommended for everyone over age 65. Certain health problems, such as chronic lung disease or some medications used to treat them, also weaken or suppress the immune system and increase your risk of infection.

Smoking increases your risk, too. In fact, smokers account for approximately 50 percent of otherwise healthy adults with invasive pneumococcal disease. A person with lung disease who smokes is at even greater risk. The good news: Quitting smoking reduces your chances of becoming infected. A study published in The New England Journal of Medicine reported that the risk of invasive pneumococcal disease was reduced by about 14 percent each year after quitting smoking.

New Vaccine vs. Old Vaccine

Surprisingly, the traditionally administered vaccine (23-valent pneumococcal polysaccharide, or Pneumovax 23—so named because it contains 23 strains of the bacteria) is not terribly effective at reducing a person's risk of developing community-acquired pneumonia. It is, however, much more effective at reducing a person's risk of developing bacteremia or meningitis caused by those 23 strains in healthy adults.

Researchers developed the new vaccine (pneumococcal 13-valent conjugate, or Prevnar 13) in hopes of improving the vaccine's ability to guard against community-acquired pneumonia caused by S. pneumoniae. To date, however, no study has shown that Prevnar 13 reduces the risk of getting pneumococcal pneumonia or invasive pneumococcal disease in adults.

What studies have shown is that Prevnar 13 appears to boost immune responses to the 13 strains common to both vaccines better than Pneumovax 23—a finding that suggests the new vaccine will ultimately be shown to be superior in preventing both conditions.

Forthcoming results from an 84,000-patient study known as Capita (Community-Acquired Pneumonia Intervention Trial in Adults) should shed more light on Prevnar 13's efficacy in preventing community-acquired pneumonia. In the meantime, the FDA has approved the vaccine for the prevention of pneumonia and invasive pneumococcal disease caused by any of the 13 strains included in the vaccine in adults age 50 and older.

Publication Review By: Peter B. Terry, M.D., M.A.

Published: 08 Aug 2013

Last Modified: 08 Aug 2013