For most people, the answer is simple: just once, shortly after you turn 65. But there are exceptions. To explain, lets go over the pneumonia vaccination, and what it does.
Pneumonia is an infection of the lungs that can be caused by many different kinds of germs. One of the most common causes of pneumonia is the germ called pneumococcus. Before antibiotics and vaccines, pneumonia caused by pneumococcus was a common cause of death.
Pneumococcus also can cause serious infection in other parts of the body, including the brain (meningitis) and the blood (bacteremia). There are many different strains of this germ that can cause pneumonia.
The Pneumovax 23 vaccine protects you against the 23 most common and serious strains that cause pneumonia. Roughly 90% of all cases of pneumonia from pneumococcus are caused by one of these 23 strains.
There is no doubt that this vaccine protects against serious, life-threatening infections of the brain and blood. Ironically, there still is controversy as to whether it lowers the risk of pneumonia.
Pretty much everyone should get a single Pneumovax shot shortly after they turn 65. If you got the shot before you turned 65, doctors often recommend a second booster shot. People who have impaired immune systems may also need more than one shot.
I once had pneumonia and bacteremia from a pneumococcus infection. I was one sick guy. Unfortunately, I was too young to have had a Pneumovax shot. I strongly urge that eligible people get this shot. About 1 in 3 people get sore, red skin in the area where they got the shot. This lasts about 2 days. But its a price worth paying.