Pneumonia

• Pneumonia, the sixth-leading cause of death in the United States, is an infection of the lungs, according to MedicineNet.com. Pneumonia is caused by inhaling bacteria, viruses or fungi. Although most healthy people fight off infection by coughing out the microbes or by initiating an immune response, people with chronic illness or a weakened immune system are susceptible, according to the CDC. Pneumonia is treated with antibiotics, but the disease can be fatal.
  
  

Pneumococcal Vaccine

• Pneumonia caused by certain types of bacteria can be prevented by the pneumococcal polysaccharide vaccine. PPSV protects against 23 strains of the Streptococcus pneumoniae bacteria that cause most pneumonia cases, according to the CDC. Vaccine prevention is becoming increasingly important as strains of pneumococcal bacteria develop resistance to antibiotics. The vaccine is administered to all ages, from infants to the elderly. It stimulates an immune response only against the pneumococcus strains contained in the vaccine and cannot protect against other viruses and bacteria.
  
  

Duration of Protection

• One dose of PPSV confers sufficient protection for most people. Most healthy adults develop antibodies against the 23 pneumococcal strains in the vaccine within two to three weeks after receiving the dose, according to the CDC. Booster doses are not required. Children younger than 2 years, the elderly, and people with long-term illnesses might not develop immunity to all vaccine strains of pneumococcus, or they might fail to develop resistance.
  
  

Second Doses

• The World Health Organization recommends second doses of PPSV for the elderly and others who might not develop sufficient immunity after a single dose. Pneumococcal immunity declines with age, so WHO and the CDC recommend that adults older than 65 years receive two PPSV doses. Adults who are vaccinated more than five years before age 65 are encouraged to receive a second dose after age 65. Second doses are also recommended for people who have HIV or AIDS, sickle-cell disease, cancer, leukemia, lymphoma, multiple myeloma or nephrotic syndrome; for those who have received organ or bone transplants; and for those taking medications that lower immunity, such as long-term steroids or chemotherapy.
  
  

Vaccine Side Effects

• The pneumococcal vaccine has few side effects. The most common are pain or swelling at the injection site. Fever, muscle aches, or severe reactions at the injection site are rare.