There are separate pneumonia vaccines for adults and children. The pneumococcal polysaccharide vaccine, PPSV23, is recommended for all adults age 65 and over, plus younger individuals with certain risk factors. The pneumococcal conjugate vaccine, PCV13, is recommended for children under age 5. The Centers for Disease Control provides vaccine information statements for both of these, as well as for other recommended vaccines (see References for links).
The adult pneumonia vaccine has been shown to be effective in reducing the risk of pneumonia, but its protection is far less than 100 percent. Its first limitation is the fact that pneumonia can be caused by many pathogens, including viruses, fungi, and many different species and strains of bacteria. PPSV23 primes the immune system to attack 23 types of bacteria that are most likely to cause serious disease. These are strains of the species Streptococcus pneumoniae, also called pneumococcus.
Several recent studies have provided information on how effective PPSV23 is in different groups of people. A Canadian study reported no benefits for patients who were previously hospitalized for community acquired pneumonia. Within five years, half the 2,950 patients in their study either died or were hospitalized again. Results were not significantly different between vaccinated and unvaccinated groups. Thus, more research is needed on how to protect individuals who have already experienced pneumonia infection.
Better results were obtained in a Japanese study of nursing home residents. In this randomized, placebo-controlled trial of 1,006 residents, 20.6 percent of the placebo group contracted pneumonia, compared to 12.5 percent of the vaccine group.
The most serious infections from the Streptococcus pnuemoniae bacteria are called invasive pneumococcal disease. These can affect the blood and lining of the brain as well as the lungs. A study from Spain showed that the PPSV23 vaccine is 77 percent effective in preventing these infections in adults age 60 and older.
All authors suggested continued research into pneumonia vaccines with higher effectiveness rates.